Posts
42
Joined
10/23/2025
Location
Essex, ON
CA
Hey all,
Its been around 10 hours since my bike had a top end. Not sure what piston was put in as it was by previous owner, however I know he did it as he had all the documentations from a reputable shop I know about. However im seeing the black coating of the piston coming off and these streaks on the cylinder. Is this normal?
Normal. Nothing to be concerned about.
Do you know what the streaks are from? Is it the coating wearing off or what
If it was recently replated cylinder it's usually caused by debris left after they hone the cylinder. Your supposed to throughly wash the cylinder out with soap n water after you get it back from the platers
I dont believe it was recently plated. Stock cylinder. I can see the cross hatching which is good but the streaks are a bit concerning.
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Coating is to aid in break in…nothing to worry about… if streaks cant be felt with finger nail…nothing to worry about….I have had replated cylinders show streaking or shadowing…but again..if cannot feel with finger nail, non issue…make sure air filter and intake track are spotless….continue to run it….if you are still concerned, pull top end for inspection….an hr or 2, new rings, gaskets is no big big deal…wouldn’t hurt to perform leakdown test to rule out any air leaks…..
Ok thank you,
Yea I make sure my filter and intake boot are clean. I used grease around the seal that the filter makes with the boot and also use a tacky filter oil. Never any dust when I take the filter off in the boot. Its got good compression, I think ill just keep running it and not worry too much and do a topend around 25 ro 30 hours.
Yeah, totally normal
Just a follow up,
When I eventually do the top end, should I remove the marks with a green Scotch brite pad? The green ones aren't nearly as abrasive and I heard that you can use them without damaging nikasail or whatever the coating is.
I use red scotch brite when I do a top end to deglaze cylinder, never an issue…that Nickasil is hard as….
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