Yes, 2mm is pretty big isn't it!
When I purchased the bike it was seriously over jetted, very rich, wouldn't rev clean at all. The guy I bought it from said he was selling it to buy a 4 stroke 250 because it wasn't powerful enough for him....hmmm I wonder why!
Its a 2004, I bought the bike without knowing anything about it's history, after sorting out the jetting I ran it for a short while and was quite impressed with the power. To be honest the engine didn't sound too bad.
I decided it would be a good idea to replace the piston kit, so I knew where I was.
As I said, the rings were very worn with 2mm ring end gap, even without measuring them you could spot the worn/narrow parts.
The piston looked OK, apart from a lot of dark scorches down the sides, blown past the rings.
Thankfully, the cylinder plating's in good condition and the crank main bearings and big end feel fine.
I'm also replacing the little end. I've completely stripped the power valve and given it a thorough clean. I'll be looking at the power valve mechanism/linkages as I think there's a lot of slop in the system.
Looking forward to trying it out!
