hi everyone i am new to this but i figured this would be the best shot i have now i have many atvs and had many but they never were as confusing as this so someone please help
i bought this atv not running i was told it needed a crank seal but i looked farther into the atv it has a nice blue spark and it is gaped to the spec, it is getting plenty of fuel and i even cleaned the carb 2 to make sure it wasnt plugged up still wont start, so i finely changed the crank seal and still just wont fire i even took out the plug and cranked the motor with a peice of paper near cylinder head (purpose was to wet paper with fuel and see if it lites) it ignites so fuel wasnt the issue so i checked the last thing the piston which it is brand new rings are good and has 120 compression SOMEONE PLEASE HELP THANKS

 

First off was the cylinder bored and a new oversize piston and rings installed OR just a new std piston and rings,OR just rings on existing piston??? A new top end should show at least around 140-145 psi or so. Think your problem could be here if you have good fuel supply and spark. OPT

 

sorry about all the posting my wifi is messed up and isnt acting right how do i delete posts and yes i checked all that stuff the cylinder was not bored and im not sure but the guy said it is original and i checked it had 125 compression

 

Not necessary to have posts deleted,they will just be pushed down the line If you have good spark,good fuel flow, good air supply (reed petals are not split/broken allowing too much fuel) and have replaced the crank seals,then it's usually down to the piston and rings. If new std rings are replaced on a std worn piston on a 2 stroke, lot of times it's just time and money spent that may not work out too well,especially if the cylinder is egg shaped/out of round.Compression will vary. Rings may seal good close to the top,loose ring seal against the cylinder towards the bottom stroke,etc. Unless I might be missing something,best to pull the cylinder and piston,remove the rings,insert the piston through the bottom of the cylinder and using feeler gauges while holding the piston tight against either intake or exhaust side,measure the clearance on the other side. If it's close to .005 on the feeler gauge,then it's time for a new bore job and piston assembly(I've seen em go to .006-.008 before,after that skirt damage can happen and you could hear the piston rattling like marbles in a can!) . A new over size piston should be set up between .0015 to a little over .002 max clearance. I've seen people make this mistake often on just "re ringing" a two stroke. Hope this long post helps. OPT

 

thanks so much im gonna give it a whirl again sorry for all the posts ill keep you updated and let you know if it works