I stripped the head and barrells off side 1 & 2 today following compression reading being low 130 psi and 100 psi. I've lost my repair manual so i have no accessvto specs.


Cylinder 1
middle ring 0.016" / 0.52mm
top ring 0.021" / 0.55mm

cylinder 2
middle ring 0.025" / 0.60mm
top ring 0.016" / 0.40mm

the rings have done less than 5000 miles.

the bores are silky smooth not scratched.

Click to view attachment

wrong pic removed

Click to view attachment

I am not seeing a good set of cylinders....

Rings on upside down?

Rich

If those pictures are AFTER the 5000 miles it's trash...

If those are before the rebuild then I'd say "needs refinishing, measurement and new rings if bore to piston clearance is OK".

Why would you tear-down to this level trying to find an intermittent noise?

I'd need more data regarding the compression test. Low compression is not an automatic reason to tear down.
It's a reason to do further testing to isolate issue.

Did you do a wet test as well?

Did you do a leak down test?

If the pictures are current it needed to come all the way down anyway.

Next, I'd want accurate piston to bore clearance check.

Ring clearances are swapped/weird on #1 cylinder and close to normal on #2
Freaking strange!
What were they at assembly?

I'd be ANGRY if I paid someone to rebuild...