Dang. Wasn't the CB gear.

Well, finally got around to looking into that rattling noise coming from my 426 - long freeking winter up here in NY.

Took the side cover off & there was a little, very little movement, just between the teeth of the CB gear & the teeth on the drive gear on the crank. No play at all in the drive gear & crank & the key was perfect. Still disasembled & blue lock tited back together, but still have that rattle.

There is no noticable difference in power, starting, anything, just an annoying rattle.


This has been covered just about a week ago. Look a little furthur down on the list of topics and check out "CB free play between gears" and "What's Next" I posted these last week talking about the same thing. I had the same experience about a week ago. My next step was to pull of the valve cover and check the valves and timing chain. They were fine and in the midst of doing all this and talking on this forum one guy mentioned maybe the rings ceized and it's actually piston slap. I ran my bike this weekend and it still made the noise. Now with this piston slap on my mind I looked at the exhaust and it noticed that it does through a puff of black smoke when reved. Even though it does still run great I'm going to do a compression test and depending on that I may pull the top off and inspect the piston, rings, and cyclinder. Mine is a 99 yz400 and I bought it used so who knows how many hours it really has on it.



When in doubt, GAS IT!

Where are you from in NY, I just moved from elmira, NY but still hook up with riding buddies in the area on weekends. I don't see many northeastern riders on this forum. You're right, long hard winter here in NY, PA area, fortunately I found a set of Trellborg tires and rode all winter long.

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