I've got a 79' Exciter 440. Basically stock under the hood except I premix and run iridium plugs. Last year it started to loose power in deeper snow, I can put the throttle to the handle bars and it won't make any where near it's RPM's. A real momentum killer. But as soon as i get it back out on the trail or shallower snow it will go like snot. I'm running a shorter track and rear suspension from what I believe to be an 82ish Phazer so i need all the bite and power I can get when I'm in the fields. If it were a carb problem it would act up all the time, wouldn't it? I've got questions about long tracking it, but if i can't get this fixed there's no point. Any help would be appreciated.