Fresh rebuild

[Diesel Don]

This is a fresh rebuild litterally 3 easy rides not even 2 tanks of gas yet and I have scuffs on my cylinder walls and my piston is scratched bad! I think the shop didnt bore my cylinder to the right size. Its now bored .40 over and I put a wsm in it which I got from the same shop and they knew I was going with a .40 over wsm and the wsms are tighter than normal I guess. So what to do next.. bring it to them and have it bored more and buy a new piston and ring or run the piston and rings in a fresh cylinder?

 

[darealblaster]

try to make the shop cover the sh*tty job or Take it to another shop, bore it over to a new size and use Wiseco Pistons.

 

[Blaaster]

I would be blaming a too lean a mixture for that damage,.

A too tight a piston would have shown scuff marks at the point of contact of the piston pin boss.

Did you leak test after rebuild?

Did you perform heat cycles?

Have you made sure that the jets are correct for the mods you may have.

Show me a pic of the crown and rings on the exhaust side of the piston and the underside of the crown to confirm my diagnosis.

Weisco pistons are not going to solve any of the problems you are experiencing.

 

[jbuckster07]

Looks like the cross hatching is at a really steep angle. From watching Kens vids i think he said that a 45* hatch is too steep and he suggests 30* at most. That looks to be about 45*. Although thats prolly not the problem per-say, it doest help the lubrication of the piston. Like Blaaster said, did you perform the necessary break in procedures once you got it fixed..

 

[Blaaster]

Although the hatching is steep it will hold enough oil for break in.

The problem is from overheating the crown on the exhaust side of the piston.

Air leak or incorrect jetting.

 

[Larry's Shee]

That's an unusual wear pattern there.
If you can, post pics of the top, underside of top, and intake side of piston.
Not sure about lean condition as that would be the coolest "side" of the piston.
What was your ring gap?
Are rings stuck to piston?

 

[OConnor Racing]

You have a lack, or loss of lubrication on that side of the cylinder. Probable cause is water getting into the cylinder via the intake.

 

[Awk08]

have you measured the piston to cylinder clearence ?
this will confirm/deny the shops work.
http://www.blasterforum.com/threads/how-to-measure-your-cylinder-diy.25767/

 

[Blaaster]

Although the hatching is steep it will hold enough oil for break in.

The problem is from overheating the crown on the exhaust side of the piston.

Air leak or incorrect jetting.

Now I know that I am getting past it, I sure did read the pic wrong, cannot tell in from out.

Lack of lubrication can also be caused by the use of starting fluid.

 

[Diesel Don]

The crown is really dark like a brownish black is and so isnt the underside.. it seems to have been rich I looked at the plug and I run 32:1 non ethanol 91 with yamalube. First start I reved it fpr about 5 minutes at different rpms and checked the plug looked good.. did it acouple more times. It was blowing smoke but I thought it was break in smoke.. I had new seals and everything put in last year so the shop said jt wasnt nesicary to replace em.. I put all new gaskets on it. My intake was re surfaced and I had a helicoil put in it is completly leak free.Could a clutch side seal do this? The gap looks all good to me. I dont have feeler gauges but it looks fine. Its always ran rich. I have boysen reeds full fmf gold fatty and bored .40 over

 

[Blaaster]

The scuff marks on the piston tells me it was in backwards!

Is there any damage to the intake side where the 2 windows are?

 

[Larry's Shee]

Can't ell ring end gap by looking.
What main jet are you running?
Clutch side seal would be blowing stinky/white smoke. They can leak at the collar that goes over the crank on clutch side. Maybe even keyway.

 

[Diesel Don]

Nope not backwards.. think my clutch seal is gone gunna investigate tommorow

 

[Blaaster]

Is it possible to post pics of the exhaust side of the Bore and the intake side of the piston to see wether it may have been caused by uneven heating of the piston.