Do the UFO's realy work? Looking to use on a 700 mach1 imp stock, does anybody know about drilling them out. Somebody out must know something about these things?

Bubba

I use them myself and say they definitly do work.As far as drilling, I drilled the needle jet out at the very bottom, where the jet is seated.Pilot jet is #25 , clip in 3 position on the needle, main jet up one size from what you would use.Use this as a guide line only because I have other mods besides these.I was able to go 2grams more weight with them allown.Keep in mind the c-clip should be moved down or made richer as the temps drop.I learn't the hard way.Throttle response is incredable.The air screw is set at 1+a half turns out,and the idle screw adjusted accordingly.

:) Hello

Back in 1998 I put the first set of "UFO's" in my own machine with great result !
Since then I have put together about 20 motors with "UFO's" mostly
Suzuki (Arctic Cat) & Rotax (Ski-Doo & Lynx) engines.
My riding friends are also very happy with the results of the "UFO's" in
their machines

With the Rotax "RV" motors you will need to go with very small Pilot jets !!!

SWRules

If your happy about the better throttle response great. But I can tell you and even Thunder products literature will tell you that there is NO benefit in horsepower at top end or at WOT. And the amount of gas you will waste with these in has made me take them off. Most serious racers and tuners that i know do not use them.

I used them for 8000 miles on my 96 FSS 670 and won't use them again. Very difficult to fine tune unless that's your thing. I saw very little benefit, a good clutch set-up may be a better bet. :(

after adjusting carbs throttle responce geat-felt machine pull very hard in midrange-this mod will not help your top end but made my sled pull VERY hard learned alot about tuning carbs-94 zr580 :hallo1: