Reply To: Bike sounds different – Gt125r 2012
if intake clearances are 0.10mm to 0.20mm and exhaust is 0.20 to 0.30mm = then valves should be OK?
Would you be able to tell if valves are leaking oil through their seals or did it smoke at any point ?
Take a look at this thread as it’s similar to yours in regards to rebuilds
Valve clearance, camshaft, camshaft tensioner – a problem or a serious fault?
Come back to your topic and let us know
125 PSI on both cylinders when its hot, did you chuck a tiny bit of oil in there (just a little) = Did it go up or down ? (piston rings or valve seals?)
Though… if re-installing pistons back in , it is possible the rings moved out of fashion
Normally rings are staggered like this:
======____=====
==____=====
=========___===
The _dips__ you see are the gaps in the rings, if they all line up exactly , that can cause further issues. I can’t remember the exact format off my head (have to read the manuals all over again) but check the 125 manual GV125 from this forum or even manualsLIB website for the cartoon drawings of the pistons to see how the rings get lined up. I had to do this last time as the old engine was eating oil (a stupid Yamaha it was!) , thankfully it hasn’t been too hard to do on a Hyosung bike. Just can’t mess with the vtwin-timings!!!!