stroking Posted April 7, 2010 Report Share Posted April 7, 2010 I rebuilt a stock stroke cub and now it won't run,only starts then back fires and bog out!!!! i tried a different STATOR/CDI/FLYWHEEL/COIL/and 8 different plugs....and it still did the same thing.....start up backfire out both pipes bog and shut down. i can't figure this one out. any thoughts ??? Quote Link to comment Share on other sites More sharing options...
NickisGod Posted April 7, 2010 Report Share Posted April 7, 2010 sounds like a timing issue. try 0 then +4. see what happens and if thats not it, you maybe have one clogged carb. check it out gl Quote Link to comment Share on other sites More sharing options...
stroking Posted April 7, 2010 Author Report Share Posted April 7, 2010 sounds like a timing issue. try 0 then +4. see what happens and if thats not it, you maybe have one clogged carb. check it out gl already tried that,also i checked the reeds. i can't think of anything that i have not checked. Quote Link to comment Share on other sites More sharing options...
NickisGod Posted April 7, 2010 Report Share Posted April 7, 2010 this sounds redundant but do u have a woodruff key? its just though. i can keep going on an on but just keep trouble shooting. Spark in both sides? compression per cylinder? Bad gas? Timing? bad plugs? pet cock on, or clogged? floats stuck? Bad ground? key turned on kill switch? try using some starting fluid, if it fire that means its gas and not electrical and go from there. alot of them you probably have already tried but just some food for though. gl Quote Link to comment Share on other sites More sharing options...
RadarRacing Posted April 7, 2010 Report Share Posted April 7, 2010 Pistons in backwards? Blaster pistons instead of banshee pistons? MO 573 series blaster. Pistons are used for longrod 115mm stock stroke cubs. Banshee pistons are used in stock 110mm rod apps. Did it pass a leakdown test? Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted April 7, 2010 Report Share Posted April 7, 2010 I was thinking along the lines of mismatched something,list everything including pistons/type carbs Quote Link to comment Share on other sites More sharing options...
J-Madd Posted April 7, 2010 Report Share Posted April 7, 2010 Sounds like timing to me, but you said you covered that. I had a bad flywheel that would make the engine do just as you described. It looked fine, but I guess the key way was off. Check the squish, that'll help you figure out if you have the right pistons. The usual pistons for a 68 mm, stock crank Cub are unique pistons from Trinity (I have heard there is another piston out there that works for that combo but haven't seen it.) Wiseco 9768M06800 Quote Link to comment Share on other sites More sharing options...
RadarRacing Posted April 7, 2010 Report Share Posted April 7, 2010 I've seen more than one person try to put the pitons in backwards with the ports forward toward the pipes not toward the intakes like its supposed to be. If you have the piston box and it says 68mm blaster pistons and you don't have a longrod crank then you will have no compression and have about 270 thousandths squish and It won't wanna run for sure. Quote Link to comment Share on other sites More sharing options...
stroking Posted April 8, 2010 Author Report Share Posted April 8, 2010 OK.........I checked the compression and it was 55psi on both cylinders with 17cc domes.........sooo the head came off and this is what i found. Quote Link to comment Share on other sites More sharing options...
stroking Posted April 8, 2010 Author Report Share Posted April 8, 2010 Quote Link to comment Share on other sites More sharing options...
stroking Posted April 8, 2010 Author Report Share Posted April 8, 2010 the owner called wicked and found that they sent the wrong piston. these are for a 4mil,not a stock stroke. guess i found another side effect of tooo loose squish. Quote Link to comment Share on other sites More sharing options...
NickisGod Posted April 8, 2010 Report Share Posted April 8, 2010 so is this taken care of? any damage? Quote Link to comment Share on other sites More sharing options...
stroking Posted April 8, 2010 Author Report Share Posted April 8, 2010 so is this taken care of? any damage? no damage,there out and the correct ones are on the way Quote Link to comment Share on other sites More sharing options...
stroking Posted April 8, 2010 Author Report Share Posted April 8, 2010 If you have the piston box and it says 68mm blaster pistons and you don't have a longrod crank then you will have no compression and have about 270 thousandths squish and It won't wanna run for sure. you were right on the money!! Quote Link to comment Share on other sites More sharing options...
firebanshee Posted April 8, 2010 Report Share Posted April 8, 2010 Just oreder the 4 mil crank Quote Link to comment Share on other sites More sharing options...
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