Engine Running Lean

[masterblaster97]

I don't know what the fu(k is going on, but my quad is acting up again. I completely rebuilt it about 2 months ago. I had it jet perfectly, and the plugs were coming out brown. Now, all of a sudden, they are coming out white, and the quad is running like sh!t. I checked and cleaned the carb, and it's all fine. I also have compression. It barely even wants to run now. I am getting pissed off at this thing. Please help!!!!!!!

 

[ruthless_one3k]

sounds like a typical air leak problem. but also remember that as the weather gets colder the air is denser therefore you may need to re-jet most people say go up one jet size for every 20 degree drop in temp. altitude changes also require similar attention. the higher you go the smaller the jet and the lower the bigger

 

[masterblaster97]

I've got the biggest jet (148) that came with my carb jet kit in it. Why was it running fine the last time that I rode it, and then I go to start it up two days later, and this is what I get. Pissing me right the fu(k off!

 

[CC&Fabb]

could be a problem that has just gotten worst. like a crack in the air boot would not just happen over one day. it would take a while to start and then eventually be broken. any rubber part is going to wear out just like a car belt of coolant tube.

 

[quam]

yup sounds like a vacuum leak. does the bike rev up real high by itself?
turn the bike on, then take carb spray and spray it over the carb boots, the base gasket area and the head gasket area. if the revs change then you know there's a leak and you need to replace your gaskets.