I have a 91 Blaster that has a k/n filter(no air box lid)Dg pipe,Vito's superstock piston,Vito's jet kit,vito's degree key and 280 main jet.The problem I am having is with the jetting. This is from a dead stop and going full throttle through all the gears. 1st and 2nd gear have no problems. 3rd is somewhat ok until the power band kicks in. 4th 5th and 6th skip. It is like a studder. the motor skips. Should I go down one size on the jet. The spark plug is on the dark side.The needle clip is set in the middle. I will be very grateful for any help.

 

whats the degree key do and super stock piston?

 

Vito's performance claims the degree key adds 2.5hp. I did notice a difference in power when I added it. The super stock piston, is a modified wiseco piston. 5hp gain.

 

I beleive I can solve your problem. The gears dont matter, its the throttle position. If its skipping at full throttle, your definately running too rich. Keep lowering the jets untill you can pin the throttle and theres no problems. Also, pay attention to your speed, if your going faster and about 3/4 throttle than full throttle, than your way too lean, but im pretty sure your too rich.
What kind of carb are you using? Look at my mods below, and im only running 220 jets.

 

I am not sure about the carb, I will have to look. I am assuming that it is stock. I bought it used. I went to a 270 jet today and 3rd is now real stong, 4th is better and 5th and 6th are still skipping. I thought that the stock jet for a blaster was a 230. I am suprised that you are only using a 220. Also, I am using a premix at 32:1. I also put in a different needle and pilot jet.

 

I have about the same mods on my blaster i put a 260 jet in it and it runs great but it does depend on the elevation! but i would say you definatley need to experiement with a smaller jet.