Should I Be concerned?

[dell30rb]

I took the exhaust pipe off of my cr80 this morning to take a peek at the piston. Here is what I found. There is zero blow by. But, what worries me is that there are one or two very very smal. black lines running up and down on the exhaust side, below the ring. The biggest one is about 1/2 inch long and very very thin. Otherwise, the piston is spotless. Next up, is that the other side of my cylinder (remember, I am looking through the exhaust port with a flashlight). The other side of the cylinder is very shiny, right opposite the exhaust port. It gets a little bit darker on either side of the shinyness, but I can still see the crosshatch everywhere on the cylinder.

This is a 2002 cr80, i've had it about 6months and it is on the origingal piston and rings. I dont know if that is anything to worry about, but this is my baby... and you know how... papa can get a little bit worried! :eek:

 

[jmics19067]

if the two black lines are oil or carbon and not a scratch that is probably only where the ring end gap is and shouldn't be much of a concern. the polishing of the intake side where the piston rides is normal also. You have nothing going on that sounds out of the ordinary. As for the wearing past limits well that is kinda hard to tell withoout actually taking everything apart and measuring. My guesstimate would be that if the bike still starts easily and has good power keep doing what you are doing. If and when the bike starts getting harder to start and/ or losing power , then it might be time to start looking at wear.

Six months does seem like a pretty long time on an 80 to me but I don't know how you ride or how well you do your maintenance. Do you have the ability to do a compression check on it? using compression figures and the sight of what you are seeing could be very instrumental in figuring if you need to take apart and measure

 

[dell30rb]

My uncle has a compression checker. I'll have to get it from him. The bike never takes more than 2 kicks to start, and runs perfect. The only maintenance I have done to the motor is change the oil every 3 rids, and clean the air filter after every ride.

I'm going to have it apart for a ring change soon, and I'll get the shop to measure the piston.

As for how I ride the bike, the first month or so, I didnt ride very hard at all, because I came off an xr80 and was not yet adjusted to my new ride. After that, I rode mostly in the powerband, and learned to slip and feather the clutch to keep the rev's high.

Thanks for the help!

 

[RM_guy]

Have them measure not only the piston but the ring end gap (while they are in the cylinder). I agree, 6 months is a long time with out a top end for an 80.

 

[dell30rb]

Ah what the heck... I'll just do the whole thing at once.

 

[marcusgunby]

I would as even if the piston measures good the skirt can break if used too long.