Blaster piston is burnt but still good

250 Killer

New Member
Jun 3, 2020
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I have a 2002 Blaster 200 and I was test riding it after just getting the engine rebuilt and as I was riding it was sounding great for a while as I still didn’t gas it or break it all the way in yet then after riding for a little bit it started making small rough noises like I was dragging a stick or something underneath and then it got louder, then it started a loud squeaking noise as it was started to lose power and bog off and did not crank anymore after. So I took the top end off and saw that my piston was burnt all around it but it was still in good shape and my piston rings where like they weren’t even touched. So I’m wondering could it be a bad crank bearing?
 
Did you do a leak down test after rebuild?
Did you retorque the head and jug after heat cycles?
What was your break-in procedure?
Did you do a leak test or compression test before you took it apart?
Can you post some pics of the piston?