Anyway.... The previous owner had given it a top end rebuild with a re bore of the non original liner (they were originally nikasil bores). When he was running it in it seized up on him. I am now in the process of rebuilding it. A new liner in the old barrel was out of the question, 1 it had already been machined and sleeved, and 2 you cant seem to get the liners for that year any more, let alone the chance of it being the same sleeve as was used last time. No over bore left, it was already max'd out. So I bought a second hand, "Good condition" original nikasil bore off of eBay, its on its way. Then I bought a standard piston.
Now the reason I am posting this here, on a primarily 4stroke forum is the witchcraft involved that I don't understand... but someone here may know more about. I'm terrified I will rebuild this thing, and again, it will nip up.....
Running in 2t seems to be an art. Kawasaki state for the KX that it needs to go through 3 heat cycles on rebuild before giving it beans... Normally I just thrash the chinese 4t engines from the off... so I think I need a new strategy with the 2t.
Kawasaki states:
1. cold - idle until warm - cold
2. cold - idle / low throttle until full temp - cold
3. cold - part mid throttle until full temp - cold
Then ride as normal.
Do you guys think this is the best route for these highly strung 2t engines?
The next question is why it seized last time? Here's a pic of the piston. Scoring on the inlet and exhaust side.
My current theory's are:
1. Thrashing from cold
2. Wrong ring gapping (apparently sometimes you have to file the rings to the right tolerance?)
3. lean running
What do you guys reckon? I need to prevent it next time, as its cost enough already
