Piston Crown Discoloration

jake_1213

Member
Nov 12, 2008
34
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When I took my motor apart this year I've noticed the underside of some of the piston crowns are turning a slight tint of brown. Looks like she might be getting a little warm. I don't know weather to blame the Sunoco fuel but I never had anything like this before with C25. I'm using the same timing and jetting that I was before with C25. I'm not sure weather to put more fuel in it or back down the timing a little. Any advise or tips tuning with the SR18 in the area of jetting and timing would be appreciated... Maybe this is normal
Thanks Jake