2010 Yz450f cylinder/piston scarring after blown headgasket

Recently my 10 450f started pissing coolant out of the overflow under heavy acceleration. We decided it must be a blown headgasket.

After tearing it down we noticed some pretty bad scarring on the piston and a little in the cylinder too.

What do you guys think could have caused this? I had just put a high flow water pump and new mishimoto radiators to resolve an overheating issue.

I guess it's big bored time, any kits you guys recommend? Any supporting mods recommended?

Thanks in advance for any info, Adam

IMG_0671.jpg

IMG_0673.jpg

20160131_180510.jpg

Edited by MiranAdam16

That looks like classic piston seizure, in this case most likely as a result of the overheating condition causing a clearance problem or an oil failure.  

 

If you're going big bore, have the crank balanced for the new piston.  Use a two compression ring piston for best longevity. 

Do you think the cylinder is worth using again with a stock replacement piston?

Edited by MiranAdam16

Doesn't look like it.  But, if you can hone it clear of any scoring/marks and then measure it to be worn less than .002" anywhere, it could be. 

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