Blown Top End *again*

HoozYerDdy

New Member
Oct 13, 2019
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Backstory: Last May I picked up a used blaster that ran GREAT. Was out riding and had a bad sputter so I pulled the carb which was suddenly clogged and put it back together. Well. Sortof, I forgot to plug the oil injector back in and my boy went off riding it and blew out the top end. Back home, I got the jug bored and piston/rings matched and I put her back together and did leakdown, compression tests and heat cycles. No break in yet...

On my next trip out my plan was for me to ride it for a day of long breaking in before I cut the boy loose on it. He's a beginner and keeps it slow anyway. But first day out he was bugging and insisted he take it out and ride it slow for the break in. Well long story short, he didn't. And I suspect he blew it again since he stranded himself way out far from camp.


Fast forward to today:

Now that it's desert season here again and we're all ready to ride except the boys blaster. So started checking things out, super low compression (30's) and has good spark (which is meaningless I know with low compression). Pulled the head off and inspected the rings via the exhaust port. Rings intact, and no scoring on the cylinder walls. But the top of the piston piston looks pretty charred. Before I tear further into this, wondering what y'all make of that char and potentual guesses as to what happened.

Is it possible I've gotten lucky and can get away with new rings, new gaskets and a proper break-in?

Thanks!
 

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