when i just had the HMF slip on, i had 150 155 main jets and moved the clip position to the second clip position and it ran fine. i unscreweed the air/fuel screws 3 1/2 turns out each, and it worked great for me.

 

Well Ill be damned, good info to have. I still say stick with those three jet sizes and your fine. Stock is 145 with 42.5 pilot

 

PS another easy way to see how it is running is to pull the plug and take a look at the top, is it black, then you are running rich, Is the plug more of a white including the threads then you are running lean. I saw a great web site on how to read plugs a while ago I will look for that

Aaron

 

wnat to know the correct jet size for a raptor 660 with a ct pipe-11:1 piston-stage one hot cam-ported / polished head- prodesign filter. Right now a have stock pilots and have a 148/150 main jets right now. i think its lean but i don't know how much?