I just bought a bike for 150 and it has a scared piston wall. It has already been sleeved. The bike running good is probably only worth 400-500 dollars. The piston was sloppy and the piston ring came loose and put a gauge in the cylinder wall. It is already bored 1mm over and I can only find a 2mm over piston but i dont think that the gauge will completely if I have it bored out another 1mm. The 2mm over piston is twice the price of a stock size piston.

So I guess the question is: How would it run if I get a new 1mm over piston and left the scar in it. The scar is a little less the 1/2 maybe 1mm deep. If it runs pretty good it would probably only cost me 40-50 to do it this way even with the top end gaskets and i can do it all myself. The good thing about doing it this way is if it does not run too good and it does not hurt the piston I can keep it and then use it if I need to have it bored out again.

If I get it bored out another 1mm and get the 2mm over piston it would cost around 80 but I still run the risk of the gauge still being in it and it still not running as good as it could.

If i get a new sleeve, stock sized piston, gaskets, and takeing it somewhere to get the sleeve pressed in will probably cost around 200.

I wont be ridding this bike a whole lot probably just messing around on the farm and maybe taking it to an off road park every now and then.


So what do you guys think i sould do???

 

Fix it right. If you still have a gouge after boring +2 over, than resleeve it and go back to the stock size. You will be better off this way and it should last longer. If you go the cheap route and the gouge is still there you will get blow by and it wont run as well.

 

I agree with JkAss................

What aftermarket piston is going to cost twice a stock one? You should be able to pick up a higher compression one at +2mm for the same price as a stock one. punching 1mm will most likley take ANY gouge out.
What bike it this work getting done on?

 

87 cr80 I bought a good jug off of ebay today and they said that it was stock bore and it could use a boring but is still pretty good as it is. well the piston was a wiseco and it was 65 dollars and most of the 1mm over pistons are around 30-40.