sizing piston kit/top end rebuild
Posted: 06:54 pm Mar 21 2015
Hi guys, I just bought a 96 kdx and started tearing into it. It wasn't revving out properly and I spent the last day rebuilding the KIPS valve. I remember how painful this was from my 98 kx250 I owned a few years ago. Unfortunately the o-ring on the one rod that actuates the subvalve got caught and torn. Does anyone know if this is important? I wonder if it would cause an air leak if run without, although without it the KIPS is butter smooth.
My second question is regarding the piston sizing. I mic'd the bore and got the following figures, not sure how to size a piston based on them, how much piston to wall clearance is required? I took 3 measurements at the top, middle and bottom of the cylinder. The bike has an unknown history I'm not sure if the cylinder was ever recoated. It might be worth noting that the engine is very noisy at idle, sounds like knocking or piston slap.
A) 2.6237 x 2.6216
B) 2.6248 x 2.6250
C) 2.6215 x 2.6215
My second question is regarding the piston sizing. I mic'd the bore and got the following figures, not sure how to size a piston based on them, how much piston to wall clearance is required? I took 3 measurements at the top, middle and bottom of the cylinder. The bike has an unknown history I'm not sure if the cylinder was ever recoated. It might be worth noting that the engine is very noisy at idle, sounds like knocking or piston slap.
A) 2.6237 x 2.6216
B) 2.6248 x 2.6250
C) 2.6215 x 2.6215