Pistion ring replace or big bore?

[thlillyr]

So can't decide what to do. Money will probably decide Anyway I have a bad piston ring. the left spark plag fouls in less than 5 minutes of running. The right side is clean and the carbs are set totatly stock. So Im burning oil on the left side which means bad piston ring. So question is:

Should I take this opportunity to put a big bore on it or just replace the rings? How much can you bore these motors out? I was hoping 500-550cc. I'm going to have a shop doing cause I'm not keen on drooping the motor myself.

 

[drewpy]

can't do that cc upgrade for a price as there is a lot of machining involved i.e. crankcase mouth, bore and piston.
Kawa gpz1100 pistons gives you 440cc and the barrels may need relining, head needs gas flowing and carbs then need setting up!

I'm assuming sohc model here as you don't tell us your bike model

 

[thlillyr]

Im DOHC 82 xs400r. That sounds like an awful lot of work. Maybe I'll just redo the piston rings. I thought it was just bore it out and put new piston on and that's it.

 

[drewpy]

you said you wanted to increase the cc, that's what is involved.

If you want to just re-bore, then get oversize pistons and rings