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Old 07-26-2013, 01:34 PM
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mapbike mapbike is offline
Motorized Bicycle Elite Member
Join Date: Mar 2010
Location: Central Texas
Posts: 5,379
Default Re: what did you do to your motor bike today?

Are those streaks actually grooves or are they just discolored areas?

The widest mark that goes all the way to top of cylinder could only be caused by something being between piston and cylinder and riding on top of top piston ring at some time or the other, the second streak is in the area that the piston ring retaining pin would be at, if it has worked out of the piston and is rubbing against cylinder wall that is why that mark is likely there.
Might not be a bad idea since your already into it this far to go ahead and pull that jug/cylinder and take a look at the piston ring retaining pin and see if it has worked out against the cylinder wall, if it has I'd get me a new piston asap or you will destroy the engine in time as that groove gets deeper.

if you cant feel a groove with your finger nail then maybe its not an issue but if you can feel a groove you have a problem, my cylinders with 1000-2000 miles on them dont look like that....

I dont always ride WOT, but when I do..I do my best to keep the rubber side down..Ride safely my friends!
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