FMF Vs. Pro Circuit (2020 Yamaha YZ450F Muffler Comparison)

Yamaha did a great job with the stock muffler and I bet if you ask any aftermarket muffler manufacturer they would tell you the same thing. If you’ve seen my social media pictures while riding the Yamaha YZ450F, you will see that I run the stock system quite a bit. Why? Because it’s really good! However, I know some of you out there will not keep the stock system on your bike because you may want something lighter, more attractive, and hopefully get something with more power than the stock system right? That is why I went to work and really picked apart the FMF and Pro Circuit systems for the bLU cRU machine. I do know that FMF and Pro Circuit have been working really hard on continuing to improve/evolve their systems for the YZ450F and after riding a ton on each, here are some of my findings.    

Pro Circuit Ti-6 Pro Versus Stock: 

Why The Ti-6 Pro? I chose the “pro” because of the smaller insert that it comes with to pass AMA/FIM sound because I have come to find out that the YZ450F loves back pressure and that smaller insert helps with throttle connection. The exhaust note on the Pro Circuit Ti-6 Pro is not near as loud or raspy sounding as the Ti-6 or T6 so that is another reason why I chose the “pro”. The exhaust note on the “pro” is deeper and slightly quieter, which I personally like more. The power delivery is slightly smoother than stock on very low RPM (4000-6000 RPM), but is only noticeable to very sensitive riders. At 10-15% throttle position there is a slightly softer RPM response, which I didn't mind on nasty, dry, choppy tracks in Southern California. If I needed more bottom on softer tracks, I simply ran a more aggressive map and that helped the “pop” I was looking for out of corners. I usually ran the TP 3.0 map with the Pro Circuit system and it made me happy with the amount of smooth roll on power I had. If you’re looking for more excitement down low and out of corners, try the “Exciting Power Character” map. (https://www.keeferinctesting.com/motocross-testing/2019/9/18/2020-yamaha-yz450f-start-upbaseline-settingstipstricks)

The rear wheel definitely feels more connected to my throttle hand and in comparison the PC system has a more seamless power delivery when transitioning to its mid range pull. The mid-range is where I could stand to get a little more power and this is exactly where the PC system delivers. The meat of the Ti-6 Pro’s power while accelerating down the next straight is noticeably better than stock. I am able to use third gear with the PC system (compared to using second gear with the stock muffler) and even though the low RPM response is slightly softer than the stock system, the mid-range RPM response is much more instant. Mid-range rpm response is crisp and makes the Yamaha feel “lighter” when trying to hop over square edge choppy areas of the track when accelerating. 

I talk a lot about using third gear on a 450 and if the bike is able to pull that gear through corners. The stock YZ450F does this very good and I was worried that putting an aftermarket muffler on would hurt this feeling. The PC system only improves this as I noticed that have been able to use lower RPM’s around the track with lower lap times. I like that I feel that I can work the clutch/shifter less with the PC system. 

Top end pulling power is as good as stock, but the PC Ti-6 Pro doesn’t have the over-rev the stock system has. If you learn to short shift the PC more and let that newfound mid range meat pull you around the track you will appreciate the phrase “work smarter, not harder” a lot more. I was impressed how the Pro Circuit Ti-6 Pro delivered as well as spread out its power and to me, made the Yamaha even more fun to ride. If that’s possible? For you weight watchers out there, you will lose around 1.2 pounds from the stock system and the PC Ti-6 Pro Titanium System runs $1,118.21. You can go to procircuit.com to get yours. 

FMF 4.1 Versus Stock:

The FMF 4.1 muffler system has a deeper more throaty sound to it (over stock) and has a louder pitch than the stock muffler system. On the track, the FMF 4.1 (on the YZ450F) makes almost as much bottom end power delivery as the stock system and keeps that peppy/exciting RPM response. The stock system has more pulling power immediately out of corners, but the FMF 4.1 allows for better traction while rolling the throttle on when the track gets slippery. Where the FMF 4.1 system really impressed me was mid range pulling power when exiting corners. The stock system is excellent in this area, but has a heavy mid range rev feel. The FMF makes the YZ450F’s engine feel free-er and gives the rider a snappier yet more powerful mid range pull with less engine braking.  

I stuck with the “TP 3.0” and “Exciting Power Character” maps on the FMF 4.1 system and that let me choose what kind of power delivery I needed at any given time of the day. With those maps and the 4.1 system you can control the power a little more down low and allow the Yamaha to have a more linear feel in second and third gear. The FMF 4.1 system has a larger muffler opening when you un-box it so make sure not to throw away your insert/spark arrestor screen that FMF includes in the box. If you think you want a little more excitement (bottom end) back into your YZ450F, simply install the insert (with the screen) and the Yamaha will get more back pressure and some more connection/bottom end pull/low rpm response, but you will lose a little of that mid range free feel that you gained.  

Up on top end the FMF pulls harder than the stock system, but falls a little short when it comes to the over-rev department. The 4.1 accepts short shifting, so if you’re like me and love to get into third gear as soon as you can, the FMF does accept that third gear shift a little earlier than stock as well. I like that FMF keeps evolving their systems with each passing model year and to me the 2020 system has some added mid range pulling power that the 2019 didn’t. The FMF 4.1 Ti muffler system will save you 1.5 pounds over stock and the cost of the FMF 4.1 titanium system runs $1099.99. You can go to fmfracing.com to get yours.


Pro Circuit Vs. FMF: 

Let me start off by saying that these are two muffler systems (for this model) that will rival or surpass (in spots) the stock system’s performance. That’s not easy to do! Some muffler manufacturers have better performance or have come up with a better setting for certain models and Pro Circuit as well as FMF have done a great job with their 2020 YZ450F system. The Pro Circuit has a little more throttle to rear wheel connection down on low end, but the FMF pulls stronger through the mid range. Up on top end both seem on par with each other and of course both have less over-rev than the stock muffler. I can lug the YZ450F in third gear more with the Pro Circuit muffler, but the FMF has more of a free feeling to it when higher up in the rpm range. These muffler systems are close in comparison to one another and offer the rider a different power curve than stock that is actually beneficial to the Yamaha YZ450F rider. 

Results:

Bottom End Pull: Pro Circuit

Mid-Range Pull:  FMF

Top End Pull:      FMF/Pro Circuit

Over-Rev:   Stock

Bottom End RPM Response: Stock

Mid RPM Response: Pro Circuit

Top End RPM Response: FMF 

Best Looking: FMF

Stock Heat Shield Mounting: FMF, Yes/Pro Circuit, No

Akrapovic Evolution Muffler System (2020 Honda CRF450R)

This is embarrassing, but I am going to be completely honest here… I think about the Honda CRF450R a lot. More than other machines. I mean I will literally wake up in the middle of the night and think of things to test in order to try and make the Honda chassis calm down a little because I see so much potential in this bike, but I need it to be calmer. It turns incredible, has an insane amount of power, and has the best ergonomics of any bike, but it lacks some comfort and predictability to me at speed. This drives me crazy because I really like this damn bike a lot! 

I stumbled across the Akrapovic Evolution muffler system as I was doing some ECU mapping with Chad at XPR Motorsports on the CRF450R. Chad does the engines for the MotoConcepts/Bullfrog Spas Honda team and I noticed that they have been running Akrapovic systems on their bikes, so I asked if I could borrow one to see how it worked. Akrapovic's Evolution line is their full titanium muffler system and includes more in the complete package than other system that I have unwrapped. The welds are beautiful and to me the quality of the complete system is second to none. Installing the Akrapovic takes a little bit of finagling, but with some patience it does line up and fit well, as long as you leave most of the bolts loose when installing. Also included in the system are some extra parts, such as a carbon fiber guard, which protects the headpipe and resonance chamber from side impact. There’s also the hardware needed for the guard, along with some extra pipe springs and rubber grommets/spacers for the exhaust cans, as well as a set of quiet/spark arrestor inserts. Keep those in (more on that later). 

Once out on the track is when I realized that this Akrapovic muffler system could actually help this Honda chassis calm down. The Evolution system lets the Honda’s engine roll on smoother at low RPM’s and that smoother feel helps the rear wheel connection as well as provides less pitching (off throttle) than the stock system. AKA MORE COMFORT!!! The Honda CRF450R now builds a smoother roll delivery and a pulling power that is longer through the mid range than the stock system. This type of character can allow you to use second gear in corners more because the second gear hit is not as abrupt or quick and that doesn't upset your technique or the chassis. The Akrapovic also allows the rider to shift later out of the corner with its increased over-rev capabilities. Pulling power up top is increased slightly as your shifting points can be altered now because of the longer pull in each gear. The mid range recovery of the Akrapovic is not as good as the stock system, but honestly that is not a bad thing. The Honda has so much power to work with that a little less “hit” as well as “recovery” actually helps me roll my corners better and allows me to be more aggressive on the Honda. I want to be able to ride this red bike and not let it ride me after 15 minutes into a moto. The Akrapovic system relaxes the engine as well off throttle. There is not nearly as much engine braking with the Evolution system and that also helps your fork from feeling harsh on small de-cel bumps.  

The pitch of the Akrapovic is ridiculously quiet when on the track and will almost give you that MXGP sound and feel. It still has that racey, crisp sound, but just not that raspy high pitch tone of the stock muffler. I preferred the quiet inserts left in because it created more back pressure and gave me more traction at the rear wheel (out of corners) in all three engine modes. I was normally a map two guy with the stock muffler, but with the Akrapovic installed I am now a map one guy all day long because of the added rear wheel/friendlier connection. 

At just over 8 pounds the system will save you almost 1.5 pounds over stock and will set you back a whopping $1547.00! Is the cost worth it? I wouldn't go that far, but it is one of the better muffler systems that I have tried on the Honda CRF450R. If I was a Honda owner I would rather invest in a Vortex ECU, have it mapped, and save a few hundred bucks, because the Vortex ECU can do more to help the power character/chassis feel than that of the Akrapovic sytem. However, if you do have a deep pocket book and are going to get a muffler system anyway, this Akrapovic would be a great choice. It’s a beautiful system and works very well on a wide variety of terrain/tracks. 

Go to akrapovic.com to locate your nearest dealer. 

Dunlop MX53 Tire Review

Dunlop recently introduced their new MX53 intermediate to hard terrain tires last week to the media at Perris Raceway. I was excited about the new tire from Dunlop because quite frankly there hasn't been an intermediate to hard terrain tire that I have been over the moon about in a very long time. I usually am stuck with running a soft to intermediate tire at most tracks, but that always isn't the best decision once second motos roll around. I have been able to ride with the new Dunlop MX53 tires at more than five different tracks, with several types of soil, over the span of seven days. I have put almost 10 engine hours on the tires as well as experimented with air pressure settings. Here is what I know about the new Dunlop MX53 tires.

Tread Pattern (From Dunlop):

Front Tire: Dunlop has introduced a horseshoe shaped cluster of knobs to the front tire of the MX53. This horseshoe pattern acts as a giant claw to dig into the ground in order to try and give the rider more traction on hard-packed terrain as well as maximize braking grip. This bold new pattern features hollowed out portions of the center of the tread. The hollow area of this horseshoe cluster results in less stiffness in the center of the tire, in order to give riders better feedback and more compliance. The MX53 also has a taller profile than the previous MX52, providing gentler handling, a higher lean angle and better maneuverability. Additionally, each of the blocks are 1 mm higher than the MX52. This extra height is crucial in allowing the MX53 to perform better in intermediate terrains than the MX52 ever did.

Rear Tire: The rear tire enhancements include a reemergence of Dunlop’s Tornado Wave block distribution. The staggered placement of the rear tire blocks provide a more linear land ratio for a better ride compliance. The consistent placement of knobs along the shoulder of the tire increases confidence at greater lean angles. However, the interior blocks have more separation, which allows loose soil from softer terrains to clear the spaces more easily, while also exposing more surface area of the knobs to the dirt when more traction is needed for harder surfaces 

Progressive Cornering Block Technology:

Dunlop’s patented Progressive Cornering Block Technology has become an industry standard. A smaller block within the traditional knob, commonly known as Block-In-A-Block, has been incorporated into Dunlop’s rear off-road tires for many generations of tire patterns. Dunlop continues to raise the bar by evolving this traditional block into altered shapes to increase durability and tire performance. 

Block-In-A-Block: The new Geomax MX53 now also features Dunlop’s patented Block-In-A-Block technology on the front tire, which allows enhanced flex on each knob resulting in ultimate grip and even more biting edges. The tie bars connecting the base of the knobs add heightened durability to enhance performance in harder terrains. The individual flex of each knob improves linear tracking and aids in steering, as the block can now flex around various terrain elements. 

The Block-In-A-Block technology in the rear tire incorporates the Diamond Block design that was introduced with great success on the MX33. The diamond shape of this altered knob increases the surface area of the block, enhancing stability and slide control. Two additional angles increase the number of biting edges to dig into the dirt. The updated Block-In-A-Block shape has also been added to the rear tire along the shoulder. This wider knob provides a steady base to maximize traction along the outer edge of the tire’s surface.The compound for the MX53 tires has a higher number of molecular polymer particles. This results in a higher fracture strength, meaning more durability. Dunlop has also added more fine carbon particles. The carbon par-ticles are responsible for grip.

Construction: In the construction process of the MX53, Dunlop has added Advanced Apex Design technology. This component of the tire’s construction is present in both the front and rear tire. The Apex of the tire previously consisted of a small strip of material wrapped around the apex of the bead. By extending this apex further into the tire’s natural construction, Dunlop is able to increase ride compliance by spreading the forces of weight on the tire across the breadth of the profile. Distributing the force in this manner increases bump absorption and allows more flex and better ride compliance. Incorporating this element strikes a perfect balance between a plush ride and a firm feel. 

On The Track: I managed to ride five different types of tracks and I will be completely honest here; I came away with a more positive outlook on these tires than after the first day of testing, at Perris Raceway. As you may or may not know I am a front end steering type of rider and I am not a fan of the Dunlop MX33 or MX52 front tires at alI. I am a picky SOB when it comes to front tires!! I was forced to purchase any remaining MX3S front tires that were available and mix matched my way around Southern California with different front to back tread patterns. 

The Dunlop MX53 front tire impressed me on the first day of testing, but it wasn't until after day two (at Glen Helen) that I realized that I could actually like an intermediate to hard terrain front tire better than a soft terrain front. The MX53 front tire lean angle traction inspires confidence in terrain that is anywhere between soft-hard pack. In pure sand conditions the front end is a little loose feeling on entrance of corners, but if the track is still fresh in the morning with tilled up loam, the front tire tracks very well. I can predict where the side of the MX53 will break loose, how much I am able to lean through corners, and that feeling never waivers throughout the course of any day. Unlike the other MX33/52 compounds where they washed unexpectedly on initial lean, the MX53 bites and give the rider predictability. Another positive aspect to the MX53 is lack of front tire sliding when braking. Grabbing a handful of front brake (lean angle or straight line) into a corner leaves the rider with a sensation of a more contact patch feel that is wider than any other Dunlop I have tried to date (especially on lean angle braking).

Flat corners (while on throttle) or medium lean angle sweepers gives me a more secure/planted feel than a MX33 or MX52 and doesn't leave me with a feel of washing the front end out. As much as I love the MX3S front tire, even that tire isn't as good in this area of the track. The carcass of the front MX53 tire also has enough cushion to where it doesn't make your front end feel harsh on braking bumps like the MX33 can do at times on intermediate/hard pack tracks. For as much time as I have on the front tire the reliability also seems to be better than the MX3S, but I will continue to put more time on the tire to see where its “breaking” point is. The overall integrity/feel of the tire still remains intact with almost 10 hours on it. The only real negative I have found to this tire is the air pressure setting is crucial, so running a 13.5 air pressure setting is the number you will need to achieve. Going higher in air pressure will leave you with less lean angle grip on dry/wet slick surfaces and going lower will leave you with a carcass that is extremely soft feeling on braking bumps. 

I am not as picky when it comes to a rear tire, but the MX53 rear tire has a narrower “terrain window” than the front tire. However, it’s still impressive on intermediate-hard terrain, it just doesn’t have much forward bite or tracking when the track has deep sand sections. If the track is softer in nature the rear tire doesn't bite into the ground as good as the front does, so if you're a rear end steering rider you may want to stick with a MX33 in softer stuff. The MX53 has a comfortable carcass feel on square edge and braking bumps, but just know 13.5 or even 14 psi is recommended. I tried Dunlop’s recommendation of 12.5, but found myself feeling the tire squish too much on the rim on acceleration bumps. When it comes to entering shallow hard pack ruts I have yet to feel anything better than a MX53 in this area of the track. The rear end tracks into the ruts superbly with a positive lean angle and lets you get on the gas earlier because the rear end of the bike feels planted sooner. Another area I gave the MX53 high marks was under braking. When braking into corners there was much less slide with the MX53 than the MX33 and that really helps when you’re asking your motorcycle for traction/bite when diving hard into a corner.

If you're a rear end steering rider, having a rear tire that slides a little more under braking might be better for you, so look into a MX33 if you’re that type of rider. Just like the front tire, being on the gas while under a medium lean angle suits the MX53 rear tire. The contact patch that the rear tire lays down for you is better than any other intermediate to hard pack terrain tire I have tried as well as allows for a more controlled scrub up faces of dry/hard pack jumps. The rear end will not want to wash as quickly up the faces of jump when leaning, which can allow for a lower trajectory. With almost 10 hours on the rear tire, its performance hasn't dwindled a huge amount and is consistent enough for me to continue to put time on it. 

On wet/slick track conditions (think hard pack with water on top) the MX53 front/rear tires fling sticky mud out from in between the knobs well enough for me to be fairly aggressive, but just note that I have yet to find a production tire that works extremely well in that type of condition. Overall, these Dunlop MX53 tires have changed my outlook on running an intermediate to hard terrain tire on a wide variety of tracks. Having a tire that is consistent enough to run in the early morning motos as well as the late afternoon motos is tough to do, but Dunlop has done a good job with providing us a tire that is capable of doing this. 

Forecasting Questions: Before my email inbox blows up with MX53 questions, let me answer some that may come through the pipeline. 

Kris, what do you like better? The MX3S or MX53? As of right now I can stand here and say for California tracks I would like to run the MX53 tires 9 months out of the year. If we get a lot of rain and the tracks are soft I will run a MX3S front and MX33 rear. If you’re an east coaster and ride soft conditions I would run a MX3S front and a MX11 rear. 

Kris, what about durability? Will these knobs chunk off? At the 10 hour mark these MX53 knobs haven't chunked off. The MX3S knobs have chunked on me around this time, but you have to know what type of tire buyer you are. Are you a performance or durability based tire purchaser? It is extremely difficult to get both of these into one tire. For me I would rather take a 10-12 hour tire that has excellent grip than a 20 hour tire that has low grip/high. However, not everyone is like me, so if you’re a weekend warrior and do not care about performance as much, but want more durability, then you might want to look into a cheaper tire manufacturer price bracket. 

Kris, what sizes do the MX53 tires come in? Dunlop offers the MX53 for all size bike ranging from 50cc-450cc including 18 inch sizes for you off-road guys. 

If you have any more questions about the Dunlop MX53 tires or even the MX3S front tire that is making its way back into production, please feel free to email at kris@keeferinctesting.com. 

FMF 4.1 RCT Muffler With SX Style Megabomb Headpipe (2020 KX450)

The Kawasaki KX450 was the most improved 450 machine of 2019 and with Kawasaki not changing anything on the 2020 KX450, I wanted to test some new aftermarket parts to see if I could improve on what I already knew from last year’s machine. I knew FMF had two headpipes available for the KX450, but until recently I wasn't able to try it. The SX Style headpipe comes down like a “lowboy” headpipe and increases the length in order to shift the power character around. So what exactly did the “SX Style” headpipe do to the KX450 and how is it compared to the MX Style headpipe? First let us tell you about the stock KX450’s power character. 

The stock power curve of the 2020 KX450 engine has a snappy throttle response from 0-10% throttle opening (with a free feel to it) and at times can almost be too touchy through corners with the standard green coupler installed. Once rolling on the throttle and passed the corner, the power is not quite as strong as the Honda or Yamaha, but still creates an easy to ride power feel on the track. I didn't necessarily need more rpm response with the 2019 KX450, but I would be lying if I said I couldn't use more bottom and mid range puling power when coming out of corners. If you go back and read my review of the MX Style FMF Megabomb headpipe with 4.1 muffler from 2019 (https://www.keeferinctesting.com/offroad-testing/2018/8/14/fmf-41-rct-titanium-muffler-system-2019-kawasaki-kx450) you will read that the MX Style Megabomb smoothed out the low end power delivery more than the stock muffler system did, but had more mid range meat, which was noticeable immediately. In a perfect world, I would love to get more of that newfound mid-range “meat” (that the MX Style and FMF 4.1muffler system brings) and shift some of it towards the bottom end. This is why my curiosity lead me to this FMF “SX Style” headpipe.  

As far as bolting on the complete system, it really is a painless install. The 2020 Kawasaki is the lightest Japanese bike in stock form, but when FMF sent me the full titanium system, I was surprised it dropped the Kawasaki’s weight by 2.4 pounds! Also this is just my opinion, but the titanium FMF 4.1 system is one of the most stunning aftermarket mufflers you can put on any bike. I love the blue anodized finish against the green plastic and it makes the whole bike pop more!

Comparing The FMF SX Style Headpipe To The MX Style FMF Megabomb Headpipe:

So how do the two headpipes with the FMF 4.1 RCT muffler compare to each other on the track? The SX Style headpipe, along with the 4.1 RCT muffler made the KX450 feel more playful out of corners than the MX style megabomb that I tried on the 2019. The low end RPM response (0-10% throttle opening) was slightly less with the SX Style headpipe (without the muffler insert), but now the KX450 had slightly more bottom end pulling power without sacrificing that extra mid-range that I liked so much from the MX Style Megabomb headpipe/4.1 muffler system. You will get slightly less pulling power on top end/length with the SX Style headpipe, but to me it was a minimal loss. Some less sensitive riders may not feel the loss of top end pull with the SX Style headpipe, but it’s something that should be noted. I prefer the SX Style headpipe on most motocross tracks simply because the KX450 pulls harder out of corners and I can shift to third gear sooner with the SX Style headpipe. 

Insert in…

You want to know a tip? Don’t throw out that insert that comes with your FMF 4.1 muffler system! Why? Because I actually liked the SX Style headpipe/4.1 muffler system better with the insert in. Why? Because it gave the muffler some added back pressure and gave me some added RPM response without sacrificing a lot of mid range pulling power. With the insert in the muffler, the KX450 now has increased (0-10% throttle opening) low RPM throttle response that I was missing through mid corner and had better corner exiting power. With the insert in you also will get more connection to the rear wheel and more traction when the track gets firmer. The sound of the 4.1 muffler with the insert in is also more pleasant and isn't as loud as the larger opening of the FMF 4.1. NOTE: Not all bikes respond to inserts/back pressure the same so just know that each bike is different. If you feel like you may need a little more low end throttle response from your FMF 4.1 muffler system, try the insert.  

 It’s tough to get more horsepower, added connectivity, as well as an overall better engine character than what a stock exhaust can give, but FMF did a good job with the 2020 Kawasaki KX450 SX Style headpipe/4.1 RCT muffler. It retained the stock system’s low end RPM response, while getting some added bottom end pulling power, as well as mid range meat coming out of corners. In order to get the SX Style headpipe when you order, you must order the SX Style headpipe separate and use the 4.1 RCT slip on. If you order the full factory 4.1 RCT system you will be getting the MX Style headpipe. The SX Style headpipe costs $349.99 and the 4.1 RCT slip on will run you $549.99. The FMF 4.1 RCT muffler also comes with a mounting bracket for the subframe tab to ensure that the tab will not break or crack. Overall, I think this is a good upgrade to your 2019-2020 K450. 

If you have any questions about this test please feel free to contact me at kris@keeferinctesting.com. I can guide you through any questions you may have. 

Ride Engineering Axle/Axle Block Kit For KTM/Husqvarna

KTM/Husqvarna uses an axle that resembles a bolt with a nut on one end. Although it’s nice not to have to mess with the left side axle block when putting in the axle through the swingarm, it’s not so friendly on the rear end of the bike while you're riding. Why? Because when you’re heavy on the throttle coming out of corners the rear end of your machine will squat under load putting force on the axle/axle blocks that sometimes can make the shock feel rigid and harsh. If the axle blocks can’t semi float (when hitting bumps under throttle) there will be some added rigidity put on the swingarm. Although crazy to think about little things like this can make a noticeable difference with the handling of your machine. 

Ride Engineering makes a KTM/Husqvarna axle/axle block kit that eliminates the one-piece axle/axle block on the KTM/Husqvarna. Instead, it uses a Honda CRF450R rear axle combined with special CNC-machined axle blocks that slip into the KTM/Husqvarna swingarm. However, you will need the special axle blocks to properly space the borrowed Honda axle. The Ride Engineering axle blocks retail for $54.95, and they offer Honda rear axles for $44.95, but how do they work? 

I am not going to sit here and blow smoke up your asses and say everyone that has a KTM/Husqvarna are going to feel this modification. Could I feel the difference when going back to back with the stock axle/Ride Engineering axle block kit? Yes, I could, but to me I only could feel it when coming out of corners with square edge as well as fast choppy conditions. After installing the Ride Engineering kit the rear of the bike felt more compliant and had less spike/harsh feel. I could feel more rear wheel traction immediately out of corners as the rear of the KTM/Husqvarna stayed straighter under throttle. I also felt like I could stiffen up my shock’s low speed compression because I had a free-er feel to the rear of the bike under load. To me a modification like this is worth it because I can actually feel more comfort. I had some of my less sensitive test riders help me with this test and one of them couldn't feel a thing, so installing the Ride Engineering Axle Block Kit should be based on how sensitive of a rider you are. 

The Ride Engineering Axle/Axle Block Kit does not add weight to the machine and in fact weighs a couple grams less than the KTM/Husqvarna axle, just in case you’re on a diet and counting your grams. The Ride Engineering axle blocks themselves come in black or orange and have a unique design that allows easy chain alignment with tabs that have markings that can be easily seen and measured off the end of the swingarm. The blocks are also 2mm shorter than stock for more gearing options.  

If you’re a sensitive rider and can feel your way around a motorcycle fairly well this Ride Engineering axle/axle block kit is a great way to get more connection out of your orange or white ride. Head over to Ride-Engineering.com to check them out. 

Fire Power Featherweight Lithium Battery

Fire Power is company owned by WPS (Western Power Sports) and they have recently come to market with a new Lithium battery to replace your OEM battery. The Fire Power battery components are designed, manufactured, assembled and packed in one location assuring high quality and consistency, are lighter than your standard OEM battery, has a built-in LED test gauge, has increased cranking amps over lead acid batteries, a fast recharge that can be brought up to a 90% charge within 6-7 minutes, has a claimed longer cycle life compared to lead acid batteries, a longer shelf life (up to 1 year before requiring recharging), can be mounted in any position, comes with no hazardous acid or heavy metals, non-explosive and non-combustible, and comes with a two-year warranty. 

We tried a Fire Power battery in our 2019 Yamaha YZ250F and our 2019 Honda CRF450R with great results. The Yamaha YZ250F is sluggish to start and absolutely hates starting in gear. The YZ250F battery also took a crap on us (completely died) only a couple months in, so a new battery was in order. After installing the Fire Power battery into our CRF450R/YZ250F not only did they fire up quicker, but starting both in gear was slightly better as well. Fitting it into both machines was easy, but we didn’t like that the little square threaded nut (inside of the posts) could fall out, if the battery was tipped, so be aware of that when installing. The Fire Power battery on the Honda is slightly smaller than the OEM battery, so there will be a little more space inside the cage (in the airbox).   

Letting our Honda sit idle in the shop for over one month proved to not be a problem for the Fire Power battery as the red bike fired up instantly. The LED test light is also a nice feature just in case you decide the night before that you want to ride the following day. Not all of us ride every weekend, so this feature helps with the rider who may take a longer breaks in between riding sessions. Simply take your seat off, push the LED test light button and make sure your good to go for the following day’s activities. 

What about weight? The stock OEM Honda CRF450R battery weighs in at 1.06 pounds and the Fire Power battery weighed in at 0.95 pounds. Cutting some weight up high on any dirt bike is essential and will improve the handling character, especially leaning into corners. is it enough weight for you guys to feel on the track? Probably not, but it doesn't hurt to lose weight and add some cranking power on a four-stroke at any time. 

For $119.95 this Fire Power battery is a fairly inexpensive way to get some starting security on longer trail rides, days at the moto track, and lose a little weight in the process. You can check out all the Fire Power products over at firepowerparts.com or if you have any questions feel free to email me at kris@keeferinctesting.com. I’m an open book!  

Yoshimura RS-4 SS/AL Full Muffler System For 2019 Kawasaki KX450

By: Dominic Cimino

Any of you that stay up to date with us here at Keefer Inc. are aware that I really enjoy riding the 2019 KX450. Like I really enjoy it. Maybe it is because we have the chassis and suspension dialed in just for me or maybe it’s just because the bike is so damn fun. Either way, I am excited to continue making improvements to this bike in the upcoming months because every time I ride it I feel faster. Next on the chopping block is the motor department and we decided to start with exhaust first. I wanted to test the RS-4 Stainless Steel Yoshimura system because I have had great luck in the past using their systems on other bikes and the guys over there always take great care of us. 

Yoshimura exhaust systems are made from scratch right here in Southern California. Their R&D facility houses everything from the race team shop, dyno/engine rooms, to the space where they lay all of their own carbon fiber. The attention to detail and quality of product is top notch in everything they produce and to give you a little more background on Yosh, you can watch this short clip:

https://www.youtube.com/watch?v=V5J5kltNfvQ

Although it is a couple years old and mainly showcases road racing disciplines, trust me when I say that it all translates equally into motocross. You can sleep peacefully knowing that your investment is going to be worth it. 

The stock exhaust system on the 2019 KX450 is not too bad overall. Beside it looking really bad (that is a no-contest) and weighing a decent amount, it produces a good tone and useable power. I think this exhaust compliments the motor and power delivery well by keeping things linear and quick revving - one of my favorite traits about this bike overall. But on the flip side, the motor does lack some “meat” in the RPM range and the over-rev tends to sign off relatively quickly at the top. Installation of the new Yosh was quick and easy with every single piece fitting in place perfectly. I love when that happens! The stainless/aluminum system that I tested weighed over a pound less than the stocker and comes in at a fair price of $675.78. In roughly ten minutes, the KX looked better instantly with the new system in place, and when I pushed the button to wake her up, she sounded healthier too. I am not a fan of obnoxiously loud exhaust systems so I was happy to listen to the Yosh when cracking the throttle on the stand. Definitely louder than stock, but not deafening. 

Before installing the new Yoshimura system, I did a couple morning motos at Glen Helen to get the best gauge of the stock comparison. The most obvious difference when cruising back onto the track was the tone, as it has a deeper/healthier sound. But when in stride, the exhaust made the KX come to life from the mid range and beyond. The linear power curve stayed true on delivery, but exemplified a more crisp powerful feel when on throttle. I felt the Yoshimura system was able to harness a little more “meat” that I have been searching for and also helped push the bike into the higher revs more efficiently. On the top end, over-rev was increased quite a bit as the KX seemed to pull longer and harder overall. I noticed when charging down Mt. Saint Helen I could hold 2nd gear almost half way down the hill before hitting the limiter. The stock exhaust would sign off way earlier than that in the beginning part of the day. I also realized I stayed in 2nd gear almost all the way around the Glen Helen circuit. This is a testament to the linear power I have been talking about on this 2019 KX450, and the Yoshimura system makes it even better. Where I didn’t notice a substantial improvement was bottom end power delivery. The KX is not a torquey bike in stock trim by any means, but I was expecting to get a little more bark with the new system. This was not the case and I found myself clutching the bike in the soft corners to wake it up in order to get back into the mid range, where I think it excels. 

Overall, the new Yoshimura exhaust system is a great performance improvement to this already great bike. Looks good, sounds good, and runs good - thats what it’s all about, right? Obviously, I am going to set my sights on continuing to improve the power delivery to round out this new KX450. I am happy with the mid/top end feel, so maybe we can experiment with new map settings to get a little more lovin’ down low.  As always, stay tuned for what is next here at Keefer Inc. If you have any questions about the 2019 KX450 please feel free to email me at dominic@keeferinctesting.com.  Or you can head over to Yoshimura-rd.com to see what they offer for your green machine.

Pro Circuit Ti-6 Pro Titanium Muffer System

The 2019 Yamaha YZ450F won the Keefer Inc. Testing shootout this year because it has all tangibles that are needed to let a rider go fast on the track with the least amount of work. I am a fan of the stock muffler system on the 2019 YZ450F, but was looking for a full system to help me lose some weight and gain a little more mid range pulling power without sacrificing low end delivery, that the stock system does so well. I went to Pro Circuit to seek out Mitch Payton and see if he would give me a Ti-6 Pro Titanium System to try out. I managed to walk out with a system, but missed out on the opportunity to speak with Mitch. He probably doesn't even know who the hell I am, but I appreciate that he got me a system to test out. I haven't tested that much Pro Circuit products in 2018, but our next couple project builds will have some PC products on board or 2019. 

The Pro Circuit Ti-6 Pro full system was created for professional racers competing in a series such as AMA Supercross or AMA Motocross to ensure they pass AMA/FIM sound regulations. The Ti-6 Pro Titanium Exhaust System is constructed of titanium throughout the head pipe, mid pipe, and canister while the end-cap is carbon fiber. I wanted the “Pro” system because I have learned that loud mufflers are not the best mufflers for power feeling on the track and sometimes putting an insert in “some” mufflers actually helps power delivery.

Installation of the PC system was painless to install (for Yamaha standards), but always make sure to install the headpipe on the cylinder head studs and then connect the mid pipe. Once the mid pipe is slipped onto the headpipe you can begin to tighten the headpipe nuts. This assures that the mid pipe doesn't bind and is free. 

So how does this sucker feel out on the track? The exhaust note on the Pro Circuit Ti-6 Pro is not near as loud or weird sounding as the Ti-6 or T6. The exhaust note on the “Pro” is deeper and slightly quieter, which I personally like more. The power delivery is slightly smoother down low, but only on throttle opening. At 0-5% throttle position there is a slightly softer RPM response, which I didn't mind on nasty, dry, choppy tracks in Southern California. If I needed more bottom I simply ran a more aggressive map and that helped the “pop” I was looking for out of corners. I usually ran the TP 2.0 map with the Pro Circuit system and it made me happy with the amount of smooth roll on power I had. The rear wheel definitely feels connected to my throttle hand and in comparison the PC system has more bottom end power than that of the Akrapovic that I tested a couple months ago. The mid-range is where I wanted more power out of the Yamaha and this is where exactly the PC system delivers. The meat of the Ti-6 Pro’s power out of corners and accelerating down the next straight is much better than stock. I am able to use second and third gears longer with the PC system (compared to stock) and even though the low RPM response is slightly softer than the stock system, the mid-range RPM response is much more instant. Mid- range RPM response is crisp and makes the Yamaha feel “lighter” when trying to hop over square edge choppy areas of the track when accelerating. Top end pulling power is as good as stock as the PC Ti-6 Pro doesn’t pull harder up top, but the PC system does have slightly more over-rev. I am able to be slightly lazier with my shifting and can decide to shift later after each corner. 

I was impressed how the Pro Circuit Ti-6 Pro delivered and spread out its power and to me made the Yamaha even more fun to ride. If that is possible? The PC Ti-6 Pro Titanium System runs $1,064.95 and is available over at procircuit.com. I will be doing a 2019 Yamaha YZ450F Muffler Shootout Podcast in the very near future, so if you want to hear how it stacks up against its competitors listen and subscribe to the Rocky Mountain ATV/MC Keefer Tested Podcast right now. 

If you have any questions about this test please feel free to email me at kris@keeferinctesting.com.

Yoshimura RS-9T Titanium Signature Muffler System For The 2019 Honda CRF450R

If there is one 2019 450 motocross machine that I think has the fastest overall engine character, it would have to be the Honda CRF450R. This engine is basically a race engine out of the crate. If you want to get to point A to point B in a quick manner, this Honda is the engine for you. So why on earth would you need more power? To me you wouldn’t need MORE, but maybe you can massage that power and move it around so that the engine delivery is slightly more controllable. This is where the KTM and Yamaha engines are better than the red machine. Both have more controlled power when the track gets rough or slippery. Controlled power is crucial in today’s 450cc world and a good muffler system can give you exactly this, if it’s a good system. Key word here people is “IF” it’s a good system. It is not as simple as reading dyno charts and slapping it on your bike. It requires real world track testing to feel the power character as well. We wanted to install/test a muffler system on our 2019 Honda CRF450R (that we purchased ourselves) to see if we could improve on a power plant that was already pretty damn impressive. We chose the Yoshimura RS-9 full titanium muffler system to try back to back with the stock system to see if it was in fact, what we were looking for.

 When we originally tested the 2017-2018 CRF450R Yoshimura RS-9 system, we thought it was a pretty damn good system that was better than stock. However, the 2019 CRF450R stock exhaust changed for the better, so Yoshimura went to work on a new headpipe design to try and achieve even more power (than the stock 2019 exhaust system). Yoshimura also wanted to tuck in the new headpipe design, so it was less susceptible to crashes.

 Once installed and on the track the Honda’s exhaust note turned from the high pitch semi raspy stock sound to a deep throaty, more traditional 450 factory race bike sound. The crack of the throttle (or RPM response) is slightly smoother and less crisp than that of the stock system, but bottom end pulling power is increased over stock. Rolling out of corners, in second or third gear lets the rear wheel find increased traction over stock and was more controllable while accelerating out of hard pack corners. The slightly smoother RPM response takes away the Honda’s exciting feel slightly, but helps you gain a little more control coming out of corners. This is what I was looking for in a Honda CRF450R muffler! The mid range pull is healthier, with more meat, than stock and while the stock system had a tough time pulling third gear in tight/slower corners (without a gearing change), the Yoshimura system will give you an easier time rolling third gear in those tighter corners. With just the flick of the clutch lever (in third gear) the Honda will be in the meat of the power once again and have you down the straight in a hurry. We noticed top end and over-rev was better than stock, as the Yoshimura system helps the Honda carry second and third gears longer. It pulls amazingly well on deeply tilled dirt in second and third gear and there wasn’t a time where I thought to myself  “I need more top end pulling power”. You could tell Yoshimura was focused on controlling, yet increasing, the bottom to mid-range pulling power when they designed this 2019 CRF450R muffler system and they succeeded in doing so. It’s also impressive that they didn’t lose any top end and over-rev in the process, in fact they got some extra!

Craftsmanship is second to none with the Yoshimura RS-9 titanium mufflers.

After weighing both the stock and Yoshimura RS-9T systems you will be saving almost two full pounds, which is great since the Honda is on the heavier side (on paper) for a 450cc motocross motorcycle. This is a significant weight loss but for $1,499.00 it is a very pricey bolt on modification. If you are looking to save a little money, Yoshimura offers the stainless steel/carbon version for $980.00, but you will not be saving much weight (only half a pound). 

Again you can’t say enough about the craftsmanship that goes into a Yoshimura system. The welds are flawless and the mufflers tuck up inside the side number plates for a stealthy, compact look. If you’re looking for a little added pulling power, with more control/connection on the track, and not to mention sexiness out your new 2019 Honda CRF450R, the Yoshimura RS-9T system will help you do all of those things very well. You will have to decide if you want to dip into your checking account to pay for these added features, but if you're in the market for a 2019 Honda CRF450R muffler, there is not a better system out there for this model. The Yoshimura system has held up great over my years of testing them and you can even send your system back for Yoshimura to re-furbish if you choose (for a fee of course). You can head over to Yoshimura-rd.com to get yours or call them at 800-634-9166.

X-trig ROCS Tech Triple Clamps And PHDS Mounts

Photos By: Jeremy Doerksen

It’s hard to find aftermarket triple clamps that are better than stock these days. So much is involved in making a triple clamp that flexes enough, but also has enough rigidity to aid the machine in corners as well. With the triple clamp flex character so important to chassis handling (on all motocross bikes) sometimes it’s tough to find anyone that can make a “comfortable” set of aftermarket triple clamps. Why do you need aftermarket triple clamps? Well sometimes it’s just for looks with some riders, but there are occasions where you might want another offset to help you get more stability or a sharper turning character out of your machine. In this case I was looking for the standard offset for a 2019 KTM 450 SX-F, but felt like the stock KTM triple clamps were a little on the rigid side when the track got hard pack and rough.  

Enter X-trig’s ROCS Tech Triple Clamps and PHDS Mounts. “ROCS” stands for “Revolutionary Opposing Clamp System”. The ROCS clamp allows for precise alignment of the fork tube with opposing clamping surface patterns, the stiffness of the steering stem is specifically tuned to the respective motorcycle model, the steering-head bearing is already mounted on the shaft tube for convenience, a special fork slot and clamping area for precise fork operation, precise clamping with special screws for low torque specs, OEM attachments can be mounted without auxiliary material, and flexibility that is adapted to the fork with anodizing in the technical factory OEM look. The difference between the ROCS “Tech” and the ROCS “Pro” is the “Tech” uses a standard offset with a pressed shaft tube. The “Pro” has two offsets you can choose from by simply adjusting the shaft tube (or steering stem). I didn't feel like the KTM needed an offset change as the KTM is predictable on straight line and corners well, so I stuck with the “Tech” clamps. 

Revolutionary Opposing Clamp System

The PHDS (Progressive Handlebar Dampening System) is a system supported by elastomers designed to absorb engine and chassis vibrations. The system also dampens the forces acting on the handlebar in a horizontal and vertical direction, maintaining steering precision. The handlebar can be adjusted in 12 different positions when the PHDS is mounted. The KTM vibrates more in the handlebar area than any other 450 motocross bike, so this is something that I feel the KTM needs, in my opinion. 

PDHS “Progressive Dampening Handlebar System”

Installation of the ROCS clamp is fairly straight forward (with the pressed shaft tube). All you need to do is grease up the steering head bearing and slide the bottom clamp up in the head tube of the frame. All of the front fender mounting points and even the OEM hour meter bolts up the same way with the X-trig clamps. Super clean! Mounting up the PHDS bar mounts is a little tricky as the mounts themselves have a lot of moving parts, so make sure to read the instructions to ensure proper mounting. Technical Touch offers optional PHDS bar mount elastomers that come in soft or firm, but I chose to run the stock medium style elastomers, which seem to be just fine for motocross conditions. 

I am super picky about bar positioning, shocking I know, so I went with the mounting hole closest to me (when sitting on bike) on the triple clamp with the PHDS mounts forward. This handlebar position gave me a +3mm bar position (forward from stock), which I preferred as the stock positioning is a little cramped for my 6’0 frame. The PHDS bar mount itself is the same height as the stock bar mount, which I was just fine with as I am using a Husqvarna Pro Taper EVO handlebar on the 2019 KTM 450 SX-F. Having so many positions available for the rider is definitely a huge positive for adjustability with these ROCS clamps. If you feel like you need a higher PHDS handlebar mount, X-trig also offers spacers to go under the PHDS mounting system. You can pick from 3mm, 5mm, and 10mm spacers.

So what did the X-trig ROCS Tech Triple Clamp and PHDS handlebar mounts do on the track? My goal for this test was to find less front end vibration, try to get a more precise front end feel through corners, without getting added rigidity on hard pack/rough straights. Basically get a more compliant KTM 450 SX-F, tough to do right? The good news is that this is exactly what I found with the X-trig ROCS Tech/PHDS system. (Full Disclosure: I have found on other machines that I tested the X-trig ROCS clamps on weren’t as favorable as this KTM test) The X-trig ROCS Tech clamp on the KTM 450 SX-F provided enough flex and doesn’t feel like it negatively affected front end bump absorption, but was also stiff enough to give me a positive front wheel feel through flat corners. The ROCS Tech clamp is most noticeable when diving deep into a rut where there is a huge load put on the front end, forced by the rider. The chassis positivity through this area is much better than the stock clamps. The stock clamps has a tendency to flex too much and give the rider a wiggle on de-cel (on deeply tilled tracks or soft dirt) or give the rider an unsettled (dive) when dropping into a long/deep rut (this sensation can only be felt mostly by faster or heavier riders). The X-trig ROCS Tech clamp gives the front end less wallow (firmer) and more cornering stability (without upsetting chassis balance). Straight line stability is as good as stock and front end bump absorption is only minimally stiffer feeling on braking bumps/square edge. 

The PHDS mounts do not vibrate nearly as much as the OEM rubber mounted bar mounts. The PHDS bar mounts flex as good as stock with the standard elastomers (up and down), but dampen vibration noticeably better around the track (especially at higher RPM’s). Slap down landings are improved slightly and front end positivity (entrance into corners) are as good as an OEM feel. Simply put the vibration characteristics the PHDS mounts provide are well worth their weight in gold. I use “weight” because they are heavier than stock ones by quite a bit, but I will gladly take some extra ounces over vibration any day. 

The cost of the X-trig ROCS Tech Triple Clamps and PHDS handlebar mounts are $800.00. The cost is more expensive than other triple clamps out on the market by a couple hundred bucks. However, there are only two triple clamps that I have tested, that to me, are as good or better than stock. If you're looking to get some of those KTM “vibes” dampened a little, pick up some front end cornering stability, and improve the looks of your KTM, X-trig has some really nice clamps and handlebar mounts available for your motocross machine. You can check out and purchase all of the X-trig products over at technicaltouchusa.com.   

If you have any questions about this test please feel free to email me at kris@keeferinctesting.com