Well i was riding my trailblazer the other day, and i putted around the woods for a bit then decided to hit the open field and opened it up. Almost immediatly i heard a loud pop and it shut down. At first i thought "great there went a seal" but then i realized my plug was out. Wasnt any visual damage to the plug or threads so i popped it back in. Then yesterday i just pulled it out of the barn and bam happened again. This time i noticed that the end of the spark plug, the electrode i guess was bent up jsut a little bit. So i ask, is it the wrong size plug? is the piston hitting the plug popping it out? Ive used this same plug since i got the quad with no problems.

 

i'd get a new one, they have a crush washer on them that will get worn out, and the vibration will make them pop out, also, make sure your getting it tight enough, torque it if you can, can't remember what the spec is

 

What plug are you currently using?

 

Yea ill probably replace it then. Its a NGK. Dont know the specific number atm.

 

just for reference the correct plug is ngk br8es

 

How does a spark plug pop out?
How does it unthread itself with a rubber boot on it?
How do you just pop it back in?

 

idk how it just pops out but it does. The threads arent messed up which puzzles me. I do t just pop it back in i meant i screw it back in.

 

Try some Teflon tape or Loctite on the threads. As to why it's popping out, the crankcase pressure is too high. All the exhaust gases aren't leaving the cylinder, they build up and out pops the plug.

Adjust the valves, check exhaust for obstructions, make sure threads aren't damaged.

With the plug plugged, the head gasket is next. Or, it could blow a hole in the head.

My .02

 

Happens more than you think on all kinds of motors. Grandpa had a 3/4 ton ford with a 400 that would blow them out all the time. Just get a new one and you'll be fine.