HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
johnnydeetz

Little end failure, why? Grayracer, any ideas?

2 posts in this topic

Took my motor apart for a slight rattle noise, plus the fact it was changing 2 gears at once sometimes, and hitting neutrals occasionally.

LH side (cam chain) main bearing had 2 thou play in it, but also I found this..

littleendyr3.jpg

Now, the piston is a new CP piston (98mm), the rod (aftermarket, Willpower rod) had 30 minutes on it when I put the new piston in (I bought the engine off a Supermono racer), and I had no reason to believe there was excessive play wwhen I put the pin in.

The piston is not hitting the head, but on the exhaust side there is no carbon build up, so its very close there, but is deffo not hitting, so I cant see it whacking the hell out of the little end, although if it was, it is on the right face of the little end to do so.

I have half a meter of phospher bronze bar, so I can easily make another (my old LC4 KTM supermono racer had one in that I made for two seasons), so I can fix it, so its not gonna cost me anything to fix. plus at the same time, I will take a few thou of the piston crown on the ex side.

The little end free play (side to side waggle) is 0.8mm (standard tolerence), there is no big end play, so the rest of the rod is OK.

I use Motul Factory Line 300V 10/40 oil, and change it after 2 meetings.

I use the bike for supermoto.

Any ideas why this would happen?

Share this post


Link to post
Share on other sites

Any number of reasons related to the material used in the bearing, the fit of the bearing, how it was installed, or conditions in the top end. :ride:

Just go over the basics.

Share this post


Link to post
Share on other sites

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
Sign in to follow this  
Followers 0