Alright ive got a raptor with only a slip on gytr pipe, and k&n filter with the flaps cut. It seems to sputter at around 1/2 - 3/4 throttle when i hold it there. I had the dealer jet it a while ago with a dynojet jet kit. The sheet says for only a slip on and k&n filter use 144 and 146. I noticed when i recently looked through the remains of my jet kit that the dealer used 146 and 148 (for pipe and head pipe). Is this whats causing my sputter? is it worth it having them change it to the correct jets? or does anyone have a nice headpipe for sale? [img]i/expressions/face-icon-small-smile.gif[/img]

Thanks for any help.

 

Between 1/2 and 3/4 throttle is the needle circuit, Id start by changing the needle hieght.
Could be lean...could be rich. First thing is figureing out whether its lean or rich.
Remove the air box lid for a test run. If it gets bettter, then it was too rich, and needs leaning.
Then try covering some of the openings with duct tape, and take another ride. If it runs better, it was too lean.
Heres an article with signs and symptoms of lean and rich.
jetting

 

Thanks for help, ill try it out.
another thing is that i have to have the air mixture screw out almost 5 full turns....

 

Don't turn the mixture screws out more than 2 1/2 turns with just a slip on. But like hondabuster said, you've got to figure out if it's lean or rich. Put in a fresh plug and find out. Then go from there.

What filter setup do you have? Pro-flow? Or are you still using the stock system with the lid holding the filter in place?

 

If the motor needs the mixture screw at 5 turns out, then you need a bigger pilot jet. 4 turns out is considered max, if it needs more, then the pilot jet needs to be bigger.
The mixture screw wont effect 1/2 to 3/4 throttle, only idle and up to 1/8 throttle.

 

Yeah, its just the stock airbox, flaps cut, K&N filter with outerwears
Thanks again

 

You're jetting should be ok. Your needles should be on the third ( middle) clip. The air screws should be around three turns out. Check and make sure your float level is correct. The fuel in the bowl should be just a fuzz above the surface where the bowl meets the carb body. Also, leave the lid on with the fins trimmed out of the snorkle.

 

Just dig into your carbs and follow the instructions on the dyno jet kit. That should solve your problems

 

dynojet instructions are awful. they assume the settings are the same for all quads and do not recognize the differences in exhaust. The instructions they give can lead to sudden engine failure due to lean conditions.