OK so I was given this quad for free it didn't have a top end at all so I got a jug from eBay and a head got the jug bored just to be safe and a new top end kit put it all together and popped off first pull ran about two tanks of gas premixed going no more than half throttle then a whole day of riding didn't open it up too much but it put in a good day at the end of the day I was letting it idle and it just dies and won't start back up and now after about 5 or 6 pulls it shoots air out carb and exhaust I am stumped its getting good spark getting fuel could it be a timeing issue like the stator moved of something

 

Gas shooting out the back of the carb is usually because the engine can't compres the gas/oil mixture and excess shoots back out.As long as top end compression is still good,I'd go for the crank seals.The one that's usually the culprit is the one behind the drive clutch.If it's leaking it can't compress the mixture properly and shoot it up the transfer ports for ignition. 2 strokes have to have good bottom end compression as well as top end.

 

Well I torn down the top end and when I pull the head off I had aide to side play in the piston and my ring gap is about .035 and I think that is a lil too much and I think that tells me the the bore was too big the seals are new

 

Ring end gap way too much. Maximum clearance on piston skirt to cylinder is .002 when you install a new piston. At .005 clearance a piston is basically worn out.Saw a lot of that over the years where too much clearance was allowed on cylinder boring.