Well, I just installed the k&n jet kit, air filter, and hmf exhaust on my grizz. Very noticable low end gain but lost top end. Tops out at 57mph with the air box lid on and 63 with the lid off. What should I do to fine tune the carb? Looking to get good low end and respectable topend without a clutch kit. By the way, before the jet kit it topped out at 62mph.

 

can't help you sry. but i would like to know how dose your gas do now with the new stuff on it. my grizz is stock and she is a gas hog. one other thing my grizz said it dose 64mph lid on, with 2 people on it. combined weight would be close to 310 pounds.

 

You have to figure out if it's running too rich or too lean. Put in a fresh spark plug, and do a wide open run as long as you can. When you have to let off, hit the kill switch and coast to a stop. Then pull the spark plug out and look at the color on the tip. White means you're lean, black means you're too rich, if the jetting is good you'll have a light brown or tan color.

If the jetting checks out ok, you can blame the loss of top end on the pipe. Generally, the more backpressure the exhaust has, the better the top end will be, and an HMF is a very free-flowing pipe. I gained a few mph on top with my hmf, but different machines will react differently to mods.