Piston Scratched - Exhaust side
#16
We were using a synthetic only based fuel for a while , lunched probably 1/2 dozen engines is exactly the same way until we figured out what was going on.
Add castor FTW
#17
#18
#19
Tech Regular
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Joined: Jun 2010
Posts: 397
It's the fuel, more specifically the oil, or lack of. I damaged my Kangaroo the same way using OD Speedblend. I have allowed adequate running in (1 gallon) but the piston seized several times during runs when I was trying to race tune the engine.
Speedblend contains 7.5% oil. Too little for on-road. I have since switched to Cosmo (12-14% oil).
Speedblend contains 7.5% oil. Too little for on-road. I have since switched to Cosmo (12-14% oil).




