Blaster Disaster

[houle54]

I have a 95 blaster. running 32:1 ratio on the gas I recently had to rebuild the engine. put maybe 6 hours on the new(pro x) piston and blew managed to bore a hole straight thru the piston head as well as scratch the front right side cylinder wall ( same spot as previously) Before I rebuild it again i was just wondering if there was another problem that i might be overlooking? Why would it over heat so much that the piston had a hole clear thru it?

[fmftrx300ex]

sounds like too much oil ...maybe...i dont run two stroke quads put am fairly exprienced in tuning them... and from wht i understand the oil lubricates but the gas is wht cools the piston so if u have a heat(lean) problem so u add more oil to the mix u reduce the piston cooling gasoline...get it?

dont go just by me but tht sound bout right

[bradley300]

the oil has nothing to do with that, i ran 32:1 myself. your problem is its running really lean. you need to get some bigger jets.

what mods do you have?

[bwamos]

I would agree with Bradley. You're running too lean at the carb. The leaner you are the hotter you run. And 2-strokes get hot FAST. Twice as many ignition strokes.

[fmftrx300ex]

hey im not a two stroke quad expert but iv read about the oil thing thought id say it.. with the 2-strokes i deal with in nitro cars ... Your goal is to run on the edge for max power.!

[quad97]

If you have a hole in the top of the piston it means that you are predetonating. this can be caused by a lean condition, air leak through a gasket (especially if the hole is off to one side of the piston), advanced timing, or poor quality fuel.

[houle54]

Thanks Everyone. I have no engine mods on the bike. I decided to rebuild the top end and while i was breaking it in it blew again i was running it Rich so it was more like 27:1 than 32:1 Just to try to cool it down. Everything was torqued to specs and the crank case was cleared of all old piston before reassembly. It blew this time and i wasn't even in the power band. I think the Crank shaft maybe bent forcing the piston rod and piston up too high. Im not a mechanic, so again thank you for the help.

[sc400ex_rider]

yes check your crank bearing and lower rod bearing.