The YFZ top speed is not near as high as I would like it. I heard that it hits the rev limiter stock so when you mod it, it does not get any faster on top speed. I am going to get a Curtis Sparks exhaust with the big core, jets, and k&n. I want to be able to keep up with the raptors on top speed. It sounds like its gonna blow up when I start getting toward the top speed but I am not even close to keeping up with the raptors so I dunno.

 

just change the gearing...go up on the front sprocket or go down on the back...or do both

 

I would keep stock gearing and buy a set of 22" medium buff extreme haulers with 8 paddles. They need to be on 8" diameter wheels. You will pick up good top speed and you will pick up a couple lengths when you race.

 

Go up one tooth in the front .

 

The YFZ can pull taller gearing, if it is top end you want, just gear it up, either with a sprocket change or larger tires. Going up in tire size may add weight though, and will be more expensive. Changing out a sprocket is cheaper and you may even lose some weight over stock.