Top 5 Mods For The 2019 Yamaha YZ450FX

Not everyone wants to “add” parts to their new dirt bikes, which is fine, but for those that must tinker, we put together a “Top 5” must haves that we would recommend. We will be doing these “Top 5” articles with all of the new 450F/250F’s (along with a couple off-road machines) and will be splitting the information up between pulpmx.com and keeferinctesting.com. These mods are recommended, by us, through countless hours of testing. If you don’t find a specific aftermarket company that you prefer in this article, don't fret, email me at kris@keeferinctesting.com and we can talk it out like adults should. Again, we will not push something on you unless we know it works. These mods that are in this article simply work for this specific machine. 

1. FMF 4.1 Slip On Muffler 

It’s no secret that the 2019 Yamaha 450FX is a great off-road competition bike, but to some it may be a surprise that in stock form it’s not legal to race at the majority of off-road races. The one thing that holds the FX back from being off-road race friendly is the lack of a spark arrestor, which 99% of off-road race organizations require in order to racer on public or even private lands.  We opted to go with an FMF slip on muffler which comes with a spark arrestor (in the box, not installed in the muffler) which gave the FX a slightly louder tone and got rid of the slightly raspy stock sounding muffler. With the spark arrestor removed the engine lost a little bottom end roll on power, but gained some over rev. With the spark arrestor insert installed, the muffler mimicked the stock characteristics and gained some mid-range. https://www.fmfracing.com/Product/ProductDetail?CategoryID=584&BikeType=MX%2FOFFROAD&BikeMake=YAMAHA&BikeModel=YZ450FX&BikeYear=2019&ItemID=044443&imaConfig=Single&ParentCategoryID=31&Priority=9 

2. Yamaha Power Tuner App

Yamaha is the first manufacturer to offer a phone app to map your motorcycle and it’s awesome! The app is very user friendly and gives you the ability to use Yamaha’s provided apps, as well as being able to make your own. Yamaha provides four maps; Mild Power, MX Power Feeling, High Revving, and Torquey. Two maps are able to load in the bike at one time and I have found myself trail riding with my phone as well as trying other maps when we come to a stop. The maps can be toggled between the handlebar mounted map switch and I have found it very handy depending on the terrain changes. https://www.yamahamotorsports.com/motocross/pages/yamaha-power-tuner-smart-phone-app 

3. Firepower Battery 

The newest generation Yamahas are very hard to start in gear, and even when in neutral they tend to turn over for longer than desired. I have found that different maps also effect how quickly the bike will fire up. So far, I have killed two batteries in the 450FX just from trail riding and constantly stopping and starting over the course of several hours. Luckily, I was able to bump start the bike both times but after the second dead stock battery I knew it was time for an upgrade. The Firepower battery was slightly lighter than the stock and has yet to leave me stranded. That being said it still doesn’t like to be started in gear.  https://www.firepowerparts.com/products/batteries    

4. Handguards

I’ve said it before and ill say it again, if a bike is designed to be an off-road bike it should come with handguards. The FX comes with a bitchin skid plate, but they decided not to add handguards on the production bike. Although for the bike’s introduction, Yamaha added GYTR flag handguards, which have been on the bike ever since. It all depends on what type of riding or racing you do, some people swear by flag style mounts, and others will not ride without full wraps, but either way, do yourself a favor and put on some type of hand protection. https://www.shopyamaha.com/product/details/cycra-rebound-hand-shields?b=Motocross+Accessories&d=42|42&ls=yamaha-motor-company&dealernumber= 

5. Fork Springs

Although the 2019 FX has much better hold up than the previous generation, the fork still has a slight diving sensation when chopping the throttle or under heavy braking. This can be somewhat fixed with clickers if you aren’t too heavy, but on my 190 pound ass (give me a break my wife is pregnant), stiffer springs will do the trick. Race Tech recommends going from the stock .46 kg/mm to a .50 kg/mm to fix the issue. I have also heard of people putting the springs from the moto bike (.51 kg/mm) and having good results. Either way, a little more hold up goes a long way when your riding gets faster and more aggressive. http://racetech.com/ChooseVehicle.aspx 

Living With The 2019 Yamaha YZ450FX By Michael Allen

It’s now been over three months since I took possession of the 2019 Yamaha YZ 450FX and I’ve been able to ride it in many different conditions. Mostly it has been used as my trail bike in the Southern California desert and mountains, but I have also raced it at a local District 37 Sprint Enduro more recently. Luckily, we’ve had a wet winter down here, so needless to say there’s nothing much better than wet dirt and an off-road 450. Overall the FX has been a fun bike to ride and has proved itself quite versatile in different terrains and scenarios. Here are some of the experiences I have had with the 2019 Yamaha YZ450FX. 

Being that the FX is designed as a “closed course” off-road race bike it’s naturally made to be more aggressive than the WR trail bike which has a VERY soft and mild mannered engine character. Although the FX is more moto related than a trail bike, that doesn’t mean that it can’t be tamed down, tailored to the rider’s skill level, and preference of riding. Yamaha now offers their power tuner app for any smart phone, which gives you the ability to load pre-set maps into the bike as well as giving you the ability to tailor your own maps. One thing that I am often asked is if the YZ450F maps will work in the FX and sadly the answer is “no”. That being said, there are plenty of FX maps out there to make your FX more aggressive and feel like a moto bike (see images for maps). Only two maps can be downloaded to the bike at one time and can be switched between the two on the fly. Personally, the two maps I like to have in the bike are “mild power” and “MX power feeling”, this gives me the ability to tackle different types of terrain and have a map that works fairly well in either faster or slower conditions. The mild power map richens up the bottom end and really helps the bike in tighter conditions where a lot of 450s are prone to flaming out. Although the mild map is really good, when riding a gear high in slow conditions the FX still benefits from having the rider cover the clutch just to make sure stalls are kept at bay. The more aggressive maps for the FX really make the bike feel just a touch off from the YZ450F with a very hard and aggressive hitting power that is great in faster, sandier conditions when you want the most power available. Having the app on your phone is genius and I would bet the other manufacturers will follow suite in coming years. I almost always have my phone on me when riding trails, so it’s really convenient to be able to try a different map when taking a trailside break (the app doesn’t need mobile service to change maps as long as you have them loaded on your phone).  

Over time (20 hours) the YZ450FX’s suspension oil/bushings had slightly broken down, which has made the damping feel a little softer than when the bike was new. I think for my weight (180 pounds) the spring rates are slightly soft when riding at a race pace (A Level), but at a trail pace the suspension settings are quite comfortable. The main places that the suspension is soft is when riding aggressively through large whoops and g-outs. The feeling I get (in those conditions) is a sensation of the fork and shock blowing through and riding slightly too low in the stroke. At the District 37 Sprint Enduro I had to check up more than I would like for g-outs because the fork and shock would bottom and it would make my feet/pegs hit the rocks in the bottom of g-outs. Stiffening up the compression on both ends of the suspension helped hold up and only minimally effected small bump absorption. This newer model FX is a better cornering bike than the previous generation by having the ability to change direction with less rider input. It may be partially in my head due to the slimmer feeling bodywork, but the newer model also feels slightly less top heavy and overall more nimble. The engine braking is much more friendlier in 2019 and ride attitude on/off throttle is much better. NOTE: Using the “MX Power Feeling” map creates less engine braking than the other maps.

The FX’s engine (in stock form) is very capable and doesn’t need much of anything to be really competitive in a race situation. The only aftermarket piece we have added to the FX is an FMF 4.1 slip-on, which was mostly needed to make the bike legal for off-road racing, since the FMF comes with a spark arrestor. The FMF took away the somewhat raspy sound that the stock muffler puts out and replaced it with a deeper tone that was slightly louder. The FMF system also helped mid range power, but slightly smoothed out the bottom end. I didn't mind the newfound delivery as the race was super technical and rocky, so having that smoother RPM response was fine for me. We will have more on the FMF 4.1 slip on system for the 2019 YZ450FX in another separate article. 

In terms of durability, I have only had two issues….. One is that the 2019 FX does NOT like to start when in gear. This doesn’t sound like that big a deal, but when it comes to races with dead engine starts this can become an issue. Also, when out on a long trail ride, in more extreme terrain, I had the battery die on me from starting and stopping frequently. With no kick start back up, I was lucky enough to be on a hill and could bump start the bike fairly easy. Once down the trail and riding a few miles, the battery would generate enough voltage to start the FX (although turning over slowly), but once the bike sat in the garage for a week, the battery lost all voltage and had to be replaced. The only other issue that I had was a blown fork seal on the caliper side. After talking with Travis Preston from Yamaha, he said that there were no nicks on the fork tube, but it could have been that the forks twisted in a small crash (I may have had a few of those) and upon compressing the front suspension, with misaligned forks, it damaged the seals. So if you ever have a crash that twists your handlebars, make sure to loosen the front end (fork pinch bolts, axle nut, etc.) completely before going back on your next ride. 

It’s no shocker that Yamaha built a great machine and I think we can all agree it’s a good thing that it’s not just the Europeans building great off-road/hybrid machines. In the future I’d like to race the FX at a few more local races and possibly try some stiffer spring rates, give you guys some added suspension specs, and work on even better maps for technical riding. After all, I need to do something to get better than a third place in the vet class (Kris says that’s not acceptable). Keep an eye out for a review on the FMF 4.1 muffler in the coming weeks over at Keeferinctesting.com and feel free to reach out to me at Michael@keeferinctesting.com if you have any questions about the 2019 Yamaha YZ 450FX. 

2019 Yamaha YZ450FX First Impression

(Editor’s Note: Dominic Cimino is one of Keefer Inc. Testing’s OG test guys. In fact, I recruited him over at Dirt Rider when I was there because he was such a solid dude. He can ride a bike at a high level, is trustworthy, is no BS and his testing skills are good because he can feel what is going on with a bike as well as communicate that to others. Dom is the epitome of a “motorcycle enthusiast” and this is what he had to say when he had the chance to ride the 2019 Yamaha YZ450FX).

I have learned that the East coast version of the term “offroad” can be different than what we are used to on the West. Single-track inside of thick forests with mud, water-crossings, wet roots, sand, and steep up/down-hills are some of the normal elements found on the east. As a proud desert rat originally hailing from Las Vegas, my version of offroad consisted of fast, open terrain - lots of rocks, whoops, and everything else that comes with the desert. But once out of my west coast bubble and into new territory, offroad riding can change dramatically. More specifically, with a focus on better introducing the media to a true GNCC experience, Yamaha hosted us on Randy Hawkin’s private property in South Carolina, with a 12 mile course that contained all of the elements previously mentioned. It was important for Yamaha to really put an effort toward showing why so much cross country R&D goes into their FX/X models, to make them shine in these east coast conditions. GNCC is a very strong sport that showcased impressive numbers in 2017: roughly 12,000 riders competed last year, in front of almost 70,000 fans. Which brings us to the 2019 450FX - a “true closed-course competition, cross country racer”, and this is my first impression after having a blast riding in the greenery of the south.

For 2019, the 450FX sees a lot of important updates that has stimulated much of the motocross model success. The bike is graced with the new chassis, updated KYB suspension, the best Power Tuner in the industry, and other offroad specific traits. Yamaha focused on making a 450 tailored specifically for tight woods riding, but also versatile enough to take it onto an open stretch of desert at high speeds. To the naked eye, it looks practically identical to the motocross bike - the only real tell-tale offroad components are the 18” rear wheel, updated kickstand, and full-coverage skid plate (which has been upgraded for 2019). But once you dive a little deeper, you will see there is much more. Most notably, the motor itself has been specifically tuned for cross country racing, with the wide ratio five speed transmission and EFI mapping/ignition timing that all compliment one another. The suspension components are sprung lighter and have valving specs that are aimed at pleasing riders on tight and technical trails. A new 2.2 gallon gas tank is stowed away nicely in the new chassis, reducing the amount of times needed to refuel. This bike is an offroad “sleeper” if you will, coming off as a motocross bike aesthetically, but harnessing almost everything you need to race at the highest levels in offroad today.

To put it lightly, this motor is an absolute monster! It has such a broad scope of power with the wide ratio transmission, that it allows you to ride the bike in many different ways. First gear is low - if you need that emergency gear to get you out of really tight sections, say no more; it can practically lug you out of the swamp. And on the complete opposite, once you hit fifth gear, forget it! Fifth gear is so fast, its like having an overdrive. The versatility of this power plant is something special, as the 450FX compliments a wide range of cross country elements, and our 12 mile test course allowed us to try most of them. On the other hand, I did notice that the engine braking character can be intense at times and I wish there was a better way to lessen it’s dramatic effect on the trail. One of the biggest stand-outs for the new year is the Power Tuner app. This standard feature lets you tune the bike anyway you want - let me try to rephrase that: you can literally customize your motor character from your cell phone, people! This is a major advancement, and after learning how to use the app on this trip and trying extreme opposite maps to really feel the differences, I was blown away with the results. Furthermore, the 2019 450FX also has an alternate map switch on the handlebar, that allows you to switch between two different maps on the fly. It comes stock with pre-programmed base settings (one aggressive, one mellow), and then as you customize your preferences in the app, those changes are reflected on top of those settings. I had two goals when testing this technology; fine tune a map specific for my personal liking, and also, load two maps that were polar opposites to one another to see how much the bike would change after you push the button. My teammate for this test, Randy, summarized it best: when we loaded the opposing maps into the bike, it was literally like have two different motorcycles at your disposal. The changes can be anything you can imagine - do you want a fire breathing 450 in map 1?  Great, its all yours.  But when you get tired in 5 minutes, do you want to tame the beast into something that feels like a 300cc trail bike? Great, push the button! It really is impressive what you can accomplish using this technology, and the app has so many other useful data traits that anyone can appreciate. Kudos to Yamaha!

A handlebar mounted map switch that let’s you go back and forth bewtween two maps while you’re riding comes standard on the 2019 YZ450FX!

When it comes to the chassis, I think it is obvious that Yamaha’s new version they introduced on the motocross bike last year has been their best in quite some time. They made substantial progress with handling characteristics and ergonomics, as the bike feels smaller and more nimble. But, I will be the first to admit - I still wish this bike could go on a diet to shed some “L-B’s.” It is a heavy motorcycle overall, and in certain sections it can feel sluggish when you need to bob & weave your way through the trees at a slower pace. Luckily, Yamaha has done a great job at centering the mass right between your legs, which greatly increased it’s agility. When riding at a faster pace, the “weight complaint” can transform into making the bike feel more stable. You can mow over some nasty sections with ease on the 450FX, which comes in handy when the going gets tough. The chassis is very forgiving overall, as the bike will not transmit unwanted force and energy into your hands or feet. The new ergonomics are my favorite, as the rider cockpit involving the seat and shroud combination is much improved. It is fun to lay it into corners with it’s narrow shrouds, and having a lower seat profile allows you to move from the front to back with ease. 

And lastly, the infamous KYB suspension components are literally the best in the business. Having the privilege to ride and test new bikes year to year has allowed me to appreciate just how good these components are. Right out of the box the fork and shock work very well, and with minor adjustments become that much better. The 2019 450FX sees the exact same components as the motocross sibling, but with specific valving and spring rates that allows the bike to perform better for GNCC and offroad riding. The fork springs are 4.6 N/mm, compared to 5.0 on the motocross bike, and the shock spring is 56 N/mm compared to a 58. Having owned the original 2016 450FX myself, these components and new valving specs are much improved. On the older bike, the forks were way too soft causing the “stinkbug effect” under any type of braking or when charging into corners. The 2019 does not have that problem, as the bike has a much better balance that allows the front and rear to work as they should. On the forks, I actually went one click out on compression and one click in on rebound, to create a more planted and plush ride in the conditions we were in. The shock is stable and predictable, and I only found myself slowing down the rebound to help when popping over roots and logs in the trees of Hawkin’s Ranch. Overall, the suspension package is impressive and I believe that it can accompany a wide range of riders and skill levels.

This experience riding the new Yamaha cross country race bikes in South Carolina was very cool. Not everyday are we exposed to riding a private, beautifully laid out GNCC course in epic conditions, and then catered to with Southern hospitality every step of the way. Riding 2019 bikes is one thing, but riding them in the environment in which they belong is a whole other ballgame. It allows you to truly appreciate the nuances and specific traits associated with being a true closed course competition offroad racer. And as Yamaha’s testing team continues to develop amazing bikes year after year, they do so with a focus on making them better in each respective category. You can trust that the 450FX is not a motocross bike in sheep’s clothing - this bike is specific to offroad in every way. I would like to thank Yamaha for providing us with a great experience, and also Mr. Hawkins for being one of the nicest, most hospitable guys in the sport (he can make a mean “shrimp boil” too). As always, please stay tuned to KeeferIncTesting.com for more coverage on offroad related materials coming your way soon. Thank you for reading! -Dominic Cimino