Midrange Bog, no idea, please help!!

Ok, here's the issue. My friend has an '01 426. Yosh pipe, boyeson accelerator cover and that's about it. The bike has awesome low end response, great top end but it seems to fall on it's face in the midrange. Say for instance you want to climb a hill, it will start off fine but once you get into the meat of the power it falls off and you have to clutch it to keep it moving. It has been at the local Yamaha dealer twice now but they can't figure anything out. So....I am coming to you guys for help. Our elevation is approx 3200 feet, temps usually around 65-75 for riding. We have half the people saying it is rich and the other half saying it is lean and no one seems to know for sure. Please help me get this figured out. I have always been a 2 stroke guy so this is new territory for me. Thanks for any help.

It might be rich in the midrange, I have experience a horrible bog by being rich onthe needle jet. If you are able to lean out the needle by moving the clip up on notch (thereby moving dropping the needle) and see if that helps out.

Reference the sticky thread on YZF jetting.

I'll give that a try, thanks alot.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now