KTM 450 SX-F Chain And Axle Position Tips

Sometimes I get to work with people that are way smarter than me and that makes me smarter on the back end. Recently, Mark Johnson of REP Suspension threw out some adjustments/numbers for me to try on the KTM 450 SX-F and I came away with a better feeling on the track. Now this article isn’t for everyone, I understand that, but for those of you that like to tinker and feel differences on the track, I think these numbers will work for you and make you smile. It’s amazing what millimeters can do to a motocross machine and sometimes it’s overwhelming on what you can do. If you want to shut your brain off and just ride, I understand, but if you want to listen to your inner test rider, give these two measurements a try on your orange brigade. The difference in feel is fairly noticeable.

Chain Slack: Most of you just do the three finger trick (and I am guilty of that as well), but if you want a little more rear wheel traction along with a more compliant shock feel look at your chain slack measurement a little harder. It doesn’t take that much to do to ensure that you have the right chain slack measurement. Getting the chain slack at measurement between 65-68mm allows there rear end to squat without binding the swinagarm upon acceleration. (*Measure from the end of the chain slider on swingarm*) I did a back to back test with a measurement of 60mm and 66mm and the difference was crazy. With 60mm of chain slack the shock felt harsh and I could feel the rear end almost had that packing sensation. When measured at 66mm the rear end had a freer feel and didn’t give me that harsh feeling when the shock was loaded. Going too loose, past the 68mm mark, gave me a feeling of less connection from the throttle to the rear wheel! Considered my mind blown! 

Axle Position: Axle position is important to the overall balance or ride attitude of the chassis. Too long can take some cornering away and too short can hurt straight line stability. So where is that sweet spot for the KTM? I have experimented with lengths before but when Mark suggested I tried 595mm, I wasn’t completely sold… Until I tried it… I was running around 608mm from the center swingarm pivot bolt to center of axle. With 595mm length I know gained a little more positive front wheel traction out of area 3 in corners and didn’t have as much squat in the rear on acceleration. This helped the ride attitude of the KTM 450 SX-F and gave me a more positive feel around three different types of tracks. Combined with a fork height of 5mm and this axle position the KTM now had a nice blend of stability and comfort that I haven’t felt before (especially on lean angle when on throttle). I use the Works Connection axle blocks or Ride Engineering axle blocks, as well as stock gearing, to achieve this measurement. I started with a new chain cut close to the desired length and allowed the natural stretch of the chain to achieve the 595mm measurement. If you’re around 2-3 mm within this measurement at any given time is close enough to achieve desired track results. When going 10mm or more off from this measurement is when you should feel changes to the KTM’s chassis character. 

2021 KTM 450 SX-F Baseline Settings/Top Mods

The 2021 KTM 450 SX-F orange brigade is an amazing machine to ride! It only gets better with some modifications and some tweaks. The KTM 450 SX-F responds well to a few mods and with that makes for one hell of a fun motorcycle to ride/race. Here are few things that you can do to make your 2021 KTM 450 SX-F better. Do one or do them all, but just note that each mod makes enough difference on the track for my tired old ass to type about it when I get back to the office.   

Engine/ECU: For 2021 KTM has a better ECU setting and although it’s clean, I still would like some more added RPM response/puling power. I have been on the Vortex ignition bandwagon for a couple years with this machine and for 2021 it hasn't wavered. If you want the same great rear wheel connection as well as more pulling power everywhere, look into a Vortex ignition from Chad at XPR Motorsports or Jamie at Twisted Development. I have turned a lot of KTM riders onto this mod and have had a 100% approval ratio. What I like about this modification is that it doesn't hurt reliability and makes for a very usable yet powerful engine for almost every type of rider. Yes, it will set you back around $800.00, but to me is much better than slapping on a muffler system and will do more for your engine. A stock re-map will not get you nearly the rpm response or pulling power that a Vortex will give you. Another good reason to get a Vortex ECU is that they have great resale value. You will also most likely be able to keep that Vortex ECU in circulation (if you get a new 2022 KTM) until 2022.5 as that will most likely be the year that KTM will release it’s new model. 

Suspension: If you haven't listened to my WP XACT Pro Components suspension podcast you may want to at least check that out, but if you're sticking with the stock suspension for a while, you can try this setting to see if this helps comfort when the track gets rough. This setting below should be in the ballpark for riders around 165-200 pounds, but if you’re heavier than 200 pounds going to a stiffer rear spring will help the ride attitude of the KTM. I have went to several tracks and tried many different settings, but this specific setting had the most “track toughness”. The KTM’s stock WP suspension doesn't quite have the comfort like the Husqvarna does, but the KTM/WP set also holds up more in the stroke, which is a better fit for me personally. To get some added comfort back with the added hold up, try this setting. 

Fork (Stock Triple Clamp): 

Height: 5mm

Air Pressure: 11.0 Bars

Compression: 13-14 clicks out

Rebound: 15 clicks out

*With KTM Hard Parts Triple Clamps or Ride Engineering Split Clamps*

Height: 5mm

Air Pressure: 11.1 Bars

Compression: 15-16 clicks out

Rebound: 13 clicks out

Shock:

Sag: 104mm

Low Speed Compression: 10 clicks out

High Speed Compression: 1-1/2 

Rebound:  11 clicks out

WP XACT Or Spring Conversion:

This is a question I get a lot! Which is better? Should I get a spring conversion or XACT Pro Component fork? I have tried Enzo’s KYB conversion as well as a REP valved XACT fork and both have their advantages. The Enzo KYB conversion soaks up small bump/hard pack chatter better than a REP XACT fork, but the REP XACT fork moves less and to me has slightly better performance with slightly less comfort. Both spring set ups are better than other re-valved AER set ups that I have tried and to me the spring set ups are way more consistent throughout the day. You will have to decide on how much money you want to spend (Enzo KYB Spring Conversion is around $2000.00 and the XACT fork is around $3000.00) as well as what type of rider you are in order to get the most out of your suspension. If you like a fork that moves in the stroke a lot and follows the ground well (front tire contact patch), the KYB conversion is great. If you want the most hold up as well as a fork that allows the rider to charge/hammer through big bumps easier, the XACT fork set up is also a great choice.  

Chassis: Aftermarket engine mounts are all the rage right now and some of you may not have the money to spend on a pair of engine mounts for your KTM. I will say that I do feel like the KTM chassis is stiff when new, but be patient as it will break in and feel better after 15 hours or so. I decided to play around with torque specs on the engine mounts for fun and stumbled across some more comfort. If you’re experiencing a stiff feeling chassis sensation and want the KTM to settle while leaning (under throttle), there is an inexpensive way to achieve some extra front end traction (as well as an overall more planted feel). You can torque all top engine mount bolts to 30Nm. This band aid will give you a more planted sensation when on throttle while leaning the KTM 450SX-F through sweepers and fast straights. You will have to make sure that all engine mount bolts have blue Loctite to ensure they do not back out (you should do this regardless if you keep all the bolts in or not). You can also try torquing your swingarm pivot bolt to 95 Nm (instead of 100Nm) to help rear end traction out of corners. The downside to doing these mods is that the chassis will flex a little more, so if you’re riding deep tilled tracks this modification might have too much flex for some (especially when chopping throttle).  

Handlebars: The stock Neken handlebar is too stiff and doesn't offer too much comfort. Throw them in the trash. Get yourself a set of Pro Taper bars and make your arms and hands happy again. The Pro Taper SX Race bar worked well for riders from 5’8 to 6’1. The SX Race bend comes in a crossbar or crossbar-less style and is 800mm width, 87mm height, 54.5 rise, and 54mm sweep. If you’re looking for a better “stand up feel” from your KTM look for handlebar close to this measurement. If you do like the stock bar try the Pro Taper Husqvarna Stock bend with 5mm bar mount risers (Ride Engineering sells these).  

Triple Clamps: After riding back to back with the stock triple clamps, the KTM factory clamps and the Ride Engineering clamps I have realized that the stock clamps are stiffer. I have since installed the Ride Engineering triple clamps on our 2021 KTM 450 SX-F with excellent results. The front end has more of a softer initial touch on slap downs and the fork action is smoother on de-cel bumps. It’s crazy to think that the fork feels softer now with the Ride clamps installed, but that is exactly how it feels when riding on the track. I was able to increase my air setting on my fork to help hold up off-throttle and kept more comfort through the entire stroke (with the stock AER fork). I also get slightly more lean angle front end traction (or cornering stability) with the Ride clamp because the front end isn't bouncing around inside long/choppy ruts. The KTM factory clamps are close in comfort to the Ride clamps, but offer slightly less straight line front tire feel.  

Rear Brake Pedal Spring: Purchase a Honda CRF450R rear brake pedal spring with the rubber around the spring. The KTM rear brake pedal spring vibrates and will break every 3-4 engine hours. Orrrrrrrrr. Get a Fasst Co rear brake return spring and be done with it! Fasst Co’s rear brake return spring offers tunable pedal resistance and a more controllable feel by placing the spring in compression instead of tension, minimizing the "on-off" feel of most rear brakes. 

Gearing: I like the stock 13/49 gearing for most conditions. If you remember last year I thought 14/52 was better in sandier conditions, but have come to the realization that I liked the gear spacing more with the 13/49 gearing. 

Twisted Development Exhaust Flanges:

The Twisted Development exhaust flanges are shaped differently than the stock OEM flange, which can change the engine character of the KTM 450 SX-F. I went through several during testing and found out a size/shape that can actually enhance the low to mid range power character. Compared to the stock piece the TD Performance flange will give you better throttle response through area 2-3 (mid to exit) of corners. Another advantage to me is that the TD flange helps pulling power out of corners as well and helps third gear lugability. The TD flange just helps the RPM’s pick up quicker, which in turn makes the KTM feel lighter when the track gets bumpy. There is no need to remap your ECU and it takes minutes to install.  

 The TD flange works with the stock headpipe/muffler system or any aftermarket system. I tried it on a stock muffler system as well as a full FMF system and with both, the TD flange helped in aforementioned areas. For $200.00 bucks, to me, it’s a great way to get a little more snap out of your KTM 450 SX-F. 

Rear Axle/Axle Blocks: Going to a Works Connection Elite axle block kit or Ride Engineering axle block kit will get rid of the fixed left axle block on the stock KTM’s axle. This will help the rear end to move more freely under throttle and improve the shock’s comfort on acceleration chop. Both are great, but you will have to decide if you want a complete axle/axle block kit like Ride Engineering’s  or just the blocks themselves like WC’s.

Muffler: To me, FMF makes the best muffler system for the KTM 450 SX-F. There are some other companies that have other bikes dialed in more, but on the KTM, FMF has got it down. You will get more low to mid RPM response as well as more mid range pulling power. Top end is increased plus the over-rev is as good as stock. It is one of the few times that I was impressed because it was actually better than stock in almost all areas. The downside is that you must keep up on muffler packing (every 10-12 engine hours) because the FMF will blow out and that could damage your expensive titanium can. Did I mention that you will lose almost two pounds with this system? If you slap on spring forks you will be gaining almost three pounds. You can get most of that back with a 4.1 Titanium FMF Muffler system.

If you have any questions about any of these settings or mods please contact me at kris@keeferinctesting.com and I am happy to help you.

2019.5 KTM 450 SX-F Factory Edition First Impression

It’s only February, but are we really seeing a 2019.5 model already? Yes, that’s right, KTM introduced the 2019.5 450 SX-F Factory Edition to us media dweebs out at Fox Raceway in Pala, California Tuesday morning. I have been putting a lot of time on an orange bike lately for an article that is up right here (50 hours on the KTM 450 SX-F) on keeferinctesting.com, so this model release came at a perfect time. A time where I can really dissect the differences between the 2019 KTM 450 SX-F and the 2019.5 KTM 450 FE. Now even though this is only a first impression, I managed to come up with ten things about this fresh orange model that you may be interested in. These beauties will be arriving in dealerships come early March. 

What are the changes to the 2019.5 KTM Factory Edition?   

Red Bull KTM Factory Racing graphics
New CP box-in-box piston & new PANKL connecting rod 

New Factory machined Anodized triple clamps 

Factory start for front fork
Orange frame
Composite skid plate

 New Akrapovič Slip-On muffler
 New Factory D.I.D DirtStar wheels

 Factory seat with Selle Dalla Valle logo
 Semi- Floating front disc
 Front brake disc guard
 Orange rear sprocket 

Engine: On paper there are only two pieces to the engine that have changed… The CP box piston and the Pankl connecting rod with brass bushing. Now with those two things in mind I wasn't expecting much change from the 2019 version, but to me the free-feeling of the engine is very noticeable in 2nd and 3rd gears. When revving the Factory Edition out in second gear there is much less engine de-cel drag than the 2019 version. The FE also feels like it pulls farther in second gear than the 19, but the overall bottom end delivery is smoother because of the Akrapovic slip on muffler. The stock muffler has more bottom end hit, but the Akrapovic, along with the engine changes, make for a stronger pulling mid range. There are two points of the Fox Raceway track where the 2019 must be shifted to third gear (out of corners), but the FE doesn’t need to be shifted and can pull second gear to the next obstacle. The top end and over-rev seem to be the same as the 2019, but that is just fine with me as the KTM FE has enough power for me. 

ECU Settings: I was told from the KTM R&D staff that the FE’s ECU settings are the same as the 2019 and that left me bewildered. Why? Because out on the track the ECU settings are so much better on the 2019.5 version than the 2019 machine that there is NO WAY they could be the same. Now I am not into conspiracy theories, but to me someone from KTM Austria must not have passed on the “updated” ECU info to the guys at the North American office. On the track the rich low end 2019 feeling is not apparent on the FE and the lean top end de-cel pop, that comes standard on the 2019, is also not there on the FE (no matter how hard you rev the 2019.5 out). Map 1 (linear pulling power with less throttle response down low, but more top end pull) and Map 2 (more pulling power/RPM response down low and slightly less pull up top) also have a distinct difference on the track and are more noticeable than the 2019 mapping choices. This is all good news for future FE buyers.  

Chassis: If you're a KTM owner you know that it takes more time to break in the 2019 steel frame compared to a Japanese aluminum framed motorcycle. I have only a few hours on this chassis and it still has that firm feel. It takes a good 7-8 hours on this frame to feel broken in or “relaxed” on the track. The FE turns as good as the 2019 version and all the same excellent “change of direction” qualities are apparent on the FE as well. Straight line stability is not the best of the 450 bunch, but not the worst neither. You can drop the WP XACT fork down to the first line (2.5mm up) like I did to help straight line stability.  

Suspension: WP has changed their branding strategy so don’t freak out about the XACT name just yet (we can explain that one in another article). I do like the silver color change that WP has done for the FE line of suspension and that color change will also be on the 2020 production models. The WP AER fork has an updated piston that allows for a tighter tolerance along with valving updates. The standard air pressure fork setting has also now gone up from 10.5 bars to 10.9 bars on the FE. The rear shock likes a sag of around 106mm now instead of 105mm, but the overall feel of the FE’s WP suspension is slightly firmer with more hold up than the 2019 model. Would I rather have a spring fork? Of course, but the updated AER fork does have some qualities that I like. I like that the front end feels light (de-cel/off-throttle) while keeping front end traction high enough so I don’t have to change my riding style up. I am a front end steering rider and the AER fork will give you what you need on initial lean. The mid stroke of the FE’s WP fork has a free-er feel and the action seems smoother than 2019, which makes for a plusher ride. The shock doesn’t feel that much different to me than the 2019, but then again, I never had a problem with the 2019 shock.  

Gearing: It comes with a 13/48, but with this Akrapovic slip on muffler I think I want a 13/49 to help with throttle response to help with recovery and second to third gear pulling power. I have also tried a 14/52 with good results as well, so feel free to try that too. 

Lightweight Feel: You would think with an engine character that is so smooth down low and linear feeling that the orange machine would feel heavy on the track, but it feels quite the opposite. It’s light, flickable, and if you want to make a sudden line change, it can do that exceptional as well. Leaning into corners and keeping it leaned all the way through the corner is the KTM FE’s strong suit. No one in the class can beat an orange bike in this category. 

Dunlop MX3S Tires: Even though you can’t purchase them anywhere anymore, these tires are still going strong on the KTM production machines. Well…. At least for another year anyway. 

Vibration: Every time I get back on a KTM from a Japanese bike I notice more vibration. The updates that KTM have made to the FE internally have improved the vibration slightly. The 2019.5 doesn't give you as much feedback to the hands as the 2019 does. Good news!  

Selle Dalla Valle Seat: This factory seat is very grippy, but also will eat your butt cheeks up on a long day of motos. The foam itself is not the problem, it’s just that the pleats on the seat are very aggressive. Just be ready to spackle the cheeks up with some Bag Balm if you're riding sand or plan on doing a long day of riding. 

Factory Trips Clamps: The KTM Hard Parts aluminum Factory CNC-machined triple clamps feature optimally tuned steering stem stiffness, in order to try and achieve perfect alignment and precise fork clamping for a highly responsive and smooth fork action. They can be adjusted to an offset of 20 or 22mm that gives you the option to change your KTM FE for different track conditions. I noticed zero added rigidity riding with KTM’s Hard Part FE clamp compared to the stock 2019 clamp. I also didn’t notice any improvements on the track (with the the FE clamp), but the orange does look factory!    

If you want to learn more about this 2019 KTM 450 SX-F Factory Edition listen to the Rocky Mountain ATV/MC Keefer Tested Podcast on iTunes, Stitcher, here on pulpmx.com, and or keeferinctesting.com right now. We try hard to give you a couple different avenues to diet your dirt bike information.   

2019 KTM 450 SX-F Review

We got our hands on the 2019 KTM 450 SX-F recently and wanted to divulge some quality testing information to all of you interested orange brigade riders out there.... 

Engine: The new 2019 KTM 450 SX-F engine isn’t any different than the 2018.5 machine besides mapping. I do feel with the updated mapping you’re getting a little more mid-range pulling power and a slightly added RPM response (at mid-range rpm) increase over the 2018.5 model. The 2019 is still silky smooth and has a very linear power, which doesn’t wear the rider out easily like some other 2019 450cc models can. The map switch is a great tool for riders that want a more smoother roll on delivery (map 1) or want a more frisky and peppy bottom end hit (map 2). I prefer map 1 in 2019 as it’s still linear enough on hard pack portions of the track, but has a cleaner hit down low to get me out of soft pockets of the track better than map 2. 

FI Setting: I do feel KTM missed the mark when it comes to the ignition/fuel mapping. The 2019 KTM 450 SX-F feels a little rich/dirty down low and a little lean on top end (de-cel popping). If KTM can get their mapping figured out, the already great engine character would be even better. I am going to go test some other maps and see if it helps with a cleaner power delivery. I know going to a Vortex ignition, that is mapped by Jamie Ellis of Twisted Development is a thing of beauty on this machine. Just FYI….

Chassis: This is where most of the changes (from the 2018) are felt on the track. The 2018 450 SX-F flexes a little too much at times off throttle (de-cel bumps) especially when the track is tilled deep or very loamy. I noticed this more when I went back east to go race than I did on the west coast. The 2019 KTM 450 SX-F is stiffer, but not harsher on choppy de-cel. This is important! Stiffer doesn’t always mean harsher! This creates a more precise feel coming into corners and also a better planted front end (yes, even with the AER fork). Did I mention it was light feeling? The 2019 KTM 450 SX-F feels like its five pounds lighter than the 2018. It’s only one pound lighter, but it feels much more lighter on direction changes. I am able to feel this on tip in leading into corners or on longer ruts. For example, a Yamaha YZ450F feels planted coming into corners, but also takes some effort to be able to lean it over (and keep it there) on longer ruts. The KTM just needs your body positioning to think about leaning over and it does it ASAP. It’s like the orange brigade is reading your mind coming into or through corners! Straight line stability is as good as the 2018 standard model, but everything is better on the 2019 model once off-throttle, which I prefer.

Suspension: I told this to Dave O’Connor at KTM. “If this bike came with a spring fork, every shootout would be yours”! You all know I am not an air fork kind of guy, but the WP AER stuff is pretty damn good (for an air fork). Does it have the front end bite of a spring fork? No, it doesn’t. Does the AER fork have mid-stroke comfort? Yes, it does. Now don’t get me wrong, the Yamaha KYB SSS fork is still better, but the AER fork isn’t atrocious like the Showa SFF-TAC Air fork was. Where the AER fork suffers is the consistency over a long day of riding. When I am riding the track at 3PM and have been there all day, the AER fork doesn’t react the same as it did at 1:30PM. It’s not as drastic as it used to be, but I still want a little more consistency in my front end. I am however getting used to how much front end feel I have with the AER and trust it more than I ever have. It gives me decent front end grip on lean in, but I would like a little more grip on flat corners where this is nothing to bank off of. Like I said, mid-stroke comfort is good on straight-line and the KTM 450 SX-F reacts well on braking bumps. The WP AER fork does have a little harsh spot on the top of its stroke when accelerating, but that is only when I went to a stiffer air setting (10.7 bars versus 10.5 bars). I would like to see a little less deflection than the KTM front end has (on acceleration). The shock is quite good on the 2019 KTM 450 SX-F and as usual has a dead feel to it. This is a great feeling on the track! Tons of rear wheel traction and less side to side movement is felt on the 2019, which gives me a feeling that I can twist the throttle harder and sooner out of corners. 

Ergonomics: The 2018 KTM 450 SX-F had a bend in the shrouds that annoyed my legs when I cornered. People complain about the Yamaha YZ450F being fat in the middle, but the 2018 KTM 450 SX-F was as fat in the shroud area (with that bend in it). The 2019 KTM doesn’t have that fat feeling or that bend any more in the shrouds! Hallelujah! The 2019 bike is very narrow feeling in the mid section and you are now able to ride up on the tank even better with the lower mounted radiators. The rider triangle (peg/seat/handlebars) is both short and tall rider friendly, but KTM needs to cut their bar width to a 803mm spec. The longer spec of the Neken bar gives me a wide feeling when I am cornering and makes me feel uneasy. I cut last year’s handlebars down to 803mm and it gave me an even better feeling coming into corners without my arms resting out too wide. You would think 7-10mm isn’t that big of a deal, but once you cut them and see, you will thank me for your new found confidence in corners. I am not a huge fan of the looks of the new seat cover, but it is much friendlier to the butt on longer rides. 

Things To Check/Carry On A Consistent Basis: I have put many hours on the 2018.5 Factory Edissssssh and know a few things that you want to check/carry more often than not. Check your spokes after break in, check your sprocket bolts every other moto or so (and blue or red Loctite them), carry a couple fuel filters in your toolbox and make sure to have an array of torx bits in that toolbox. You're welcome! 

Black Throttle Cam: The stock “gray” throttle cam to me uses a long pull (twist to full throttle). I almost have to double chicken wing it to get there at times. In order to combat that and get some more bottom end feeling, install the black throttle cam that KTM offers you. Doing this will make the KTM 450 SX-F feel more exciting out of corners and hit slightly harder/sooner. I stayed on map 1 when using the black throttle cam. 

Pankl Transmission: Under load the new 2019 transmission is much easier to shift. Not to say that the transmission on the 2018 is bad, but the buttery smooth shifting is somewhat reminiscent of some factory transmissions that I have spent some time on, in the past. Another thing that I noticed that the 2019 does better than the 2018 is that I am able to find neutral much easier (when at a stop), before I put the machine on the stand. However, while riding I have yet to hit a false neutral! Knock on wood! 

Adapting To A KTM: If you're thinking about making the 2019 KTM 450 SX-F your next bike, but are nervous about that European feel, don't stress on it. The newer KTM’s feel less foreign then they did just a few short years ago. I am able to adapt to the orange machines after coming off of Japanese machines easier than ever. 

Specs: Here are some baseline settings to start with on the 2019 KTM 450 SX-F:

Fork:

Air Pressure: 10.5-10.7 bars (depending on weight, I am 170 pounds and I like 10.7 bars to keep the front end up a little more de-cel)

Compression: If going with 10.7 bars try softening the compression up a 2-4 clicks to aid in mid-stroke comfort. If going with a stock air pressure reading go up 1-3 clicks on compression. 

Rebound: Standard

Shock: 

Sag: 105mm

Low Speed Compression: 2-3 clicks stiffer

High Speed Compression: Heavier riders (180 and up) might want to try and go with a 1/4 turn in (stiffer) on high speed compression. If you’re less than 180 pounds you can stick with stock to 1/8 turn in.

Rebound: Loamy/deep tracks go with 1-2 clicks slower. Hard pack tracks, stick with stock to 2 clicks faster.