nastyracing Posted June 5, 2012 Report Share Posted June 5, 2012 i was battling issues finally got it running hard with a richer needle. made two hard laps around track and was going 4th to 5th for the first jump on track when bike poped and shut off i pulled clutch in a limped off track. realized there was no compression and bike was not locked up. temp was at 250 degrees and bike blew antifreeze all over leg. i was expecting to see a seized compression ring to piston or just a blown head gasket. but i found this. if bike was detonating wouldnt the center of have pitting and the rest of the piston all look the same? thoes two laps before it lost compression were the best it had ran and if anything was rich on my main. only sign to this happening is the r's in the air before landing did hang a split second and cleared right out before landing and back on throttle. i sprayed carb clean around everything testing for air leaks with negative results. just baffels me that the piston is only melted down in area where the powervalve is. I am no engine builder by any means and this motor was freshly built by TSI racing in bethelem PA by previous owner with all new parts. any input would be greatly apreciated because i plan on fixing this thing and dont want to put new piston rings n gaskets in it n ten hrs later the same thing happen. Quote Link to comment Share on other sites More sharing options...
guns4children Posted June 5, 2012 Report Share Posted June 5, 2012 Props to jbird on the nice answer Quote Link to comment Share on other sites More sharing options...
Strm Trpr Posted June 5, 2012 Report Share Posted June 5, 2012 your EGT's where off the roof causing your exhaust side of the piston to melt down... it has happened to my sled twice... extended wot runs on a lean ratio... was my issue shity gas can even cause this but usually takes more then 1 tank of fuel to burn it down unless it was a really bad tank or the engine was on the ragged edge and the fuel was the cherry on top. Just by looking at your piston wash though... it has every sign pointing to lean... airleak clogged carbs lean jetting ext... however other htings that can cause the exhaust side to melt down are low octane fuel, lean jetting, air leak, too high of compression, advanced ignition timing, or a combination of all or some of these issues And incorrect Float Height... Quote Link to comment Share on other sites More sharing options...
wacko2000 Posted June 5, 2012 Report Share Posted June 5, 2012 Must have been a air leak the few rides that you took it on the bike was running well over 200degrees right? You made numerous jetting changes with little to no change! Joe Quote Link to comment Share on other sites More sharing options...
RadarRacing Posted June 5, 2012 Report Share Posted June 5, 2012 Any time the exhaust side of a piston melts it was due to a lean condition of some sort. Detonation can cause temperatures to skyrocket. Your bike actually releases a lot of heat out the exhaust. Quote Link to comment Share on other sites More sharing options...
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