There's a lot of talk out there about the brand new 2023 Yamaha YZ450F. There is a lot of us who still have the 2018 to 2022 YZ450F, and it's still a great bike. It's very reliable and those years still have lots of power handles as well. There's no reason to just get rid of it, so let's talk about a few simple upgrades that are bolt on and will not reduce reliability. I'm calling it a "Limited Package" because it has simple bolt on items. I have done this already to my son's 2019 YZ450F and we have been racing it for the last 2 years this way. The bike runs strong and has never let us down. Every item listed below are parts you can install yourself in your own garage using basic tools.
I will be modifying the air intake, exhaust system, changing the rear sprocket (gearing) and installing a Rekluse Racing manual Torqdrive Clutch that works with OEM stock clutch basket, hub, and pressure plate.
The first modification is the air intake.
OK, the first thing we will start with is the air intake system. There are two ways to go there: the least expensive version, the No Toil Super Flo Filter Kit or you can always go with the Twin Air Powerflow Kit. Both brands of the intake system will produce the same results in performance. The only difference is the No Toil Super Flo System is plastic and the Twin Air Powerflow Kit system is bullet aluminum. Some riders do feel more comfortable with the Twin Air system because it is built a little sturdier, but the price is three times the amount of the No Toil system. I have used the No Toil for over two years and never had a problem. The horsepower gain from using a cageless intake system is 1 1/2-2 hp. Also, the bike will be slightly louder.
The next area to improve on is the exhaust system. We also have two great choices for performance exhaust. The best results came from using a slip-on system over a full system. We were able to maintain good low-end performance and greatly improve the mid-range to over rev. First choice is FMF Aluminum Factory 4.1 RCT (Slip-On) Carbon Fiber End Cap. The second choice is the Yoshimura RS-4 Aluminum Canister/Carbon Fiber End Cap Exhaust Slip-On. The two systems performed equally, but if I had to choose I would us the FMF as the transition from mid to top was smoother. I pasted below a dyno map for the Yoshimura, not the FMF (gains are slimier).
The next area is the clutch, putting the horsepower to the ground. A high-performance manual clutch will increase your bikes performance. This is a simple clutch replacement. The OEM clutch basket, hub and pressure plate are still used. You will see improvement in the torque, about 25%, and eliminate clutch slippage. This will allow you to use the full potential from your motor without any performance modifications. The Rekluse TorqDrive Clutch Kit will also extend clutch life, at least double from what you normally would expect. In our case, we have gone over a year and still have the same clutch in the bike.
The last thing is a simple rear sprocket change from a 49 tooth to a 50 tooth sprocket. I like using a lightweight aluminum sprocket. The only problem is how quickly the aluminum sprocket wears out. When going up 1 tooth on the sprocket, I feel the bikes pulls stronger from 2nd-3rd gear. The next choice is a steel sprocket which has great longevity, but a little heavy and the do not look so good either. So the best compromise is a Dual Ring Sprocket from Moose Racing. They are a combination of an aluminum inner ring and a outer Steel Ring for longevity. Now most Twin Ring Sprockets retails between $105-$135. The Moose Racing Dual Ring sprocket retails for $69.95.
The last thing is to use the Yamaha Power Tuner Phone app.
2018-2019 YZ450F MAP 2 - TP 2.0 / CONNECTED RESPONSE
(Improved low RPM feel / increased torque feeling.)
2020 YZ450F MAP - TP3 / CONNECTED RESPONSE
(Improved low RPM feel with longer over-rev.)
2021-2022 YZ250F MAP - EXCITING POWER
(LOW - MID PULLING POWER FEEL)
All the modifications work with most Japanese motocross bikes - so if you do not have the same motocross bike that listed above we can help guide you to correct products to receive similar gains. The main goal of this package is to greatly improve your bike and maintain reliability.