I have an 02' blaster that has a Toomey pipe and a K&N air filter. I am running a 310 main jet because thats what came with my pipe. The airbix lid is also removed. The first few months that i had this pipe, my quad ran great. But then it started to bog out more and more but the carb was always spotless. So i would change the plug and usually it would run for a few hours and then the same thing would happen again. I thought that the problem was that the jetting toomey sent me was just the wrong size but i put my stock pipe and stock jetting back on and it still did the same thing. It ran great for a few hours and then would get worse and worse but when i change the plug it runs good again. I dont think the plugs completely foul because my quad can still start up it just doesnt run good. I can hold the throttle wide open and it wont rev high at all it just boggs out. Could the problem be that the float height is off? The air screw and pilot jet are also at the correct settings. The only thing i havent checked was the float height because i dont know how.

 

Sounds a litle rich?

We used to have a Blaster with an FMF fatty, and a K&N, and we (I believe) only had a 290-300 main jet in it.

If you are fouling plugs, its best to go down a jet size or two and do a plug check with a fresh spark-plug.[img]i/expressions/face-icon-small-wink.gif[/img]

Is your compression ok? Low compression can also cause a person to foul sparkplugs.

 

Check your reeds. All it takes is a chipped reed to have the problems you are having. Good luck.