Re: what did you do to your motor bike today?
Originally Posted by mapbike
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....
Well, it's back together. The streaks are grooves. I don't think the retaining pin is the problem, because if you look, both are just to the right of the exhaust port. If it were the retaining pin wouldn't it be right on with the transfer port? It just doesn't make sense, engine runs well, no weird noises, has good power. I dunno, maybe when I get a job I'll just replace the top end on it and call it a day. Granted, by that time I'd probably be looking at a complete engine replacement. (dax lower, you know.
2 WHEELS: '11 Huffy Good Vibrations, '11 Skyhawk GT5, 44t, CNSV2, NGK BPR7HIX, Bosch wire, shutupexhaust, 26x1.75kevlar tires, Tektro C230's, new stupid Bell chain