why I want the centrifugal clutch

Recently I asked about a centrifugal clutch for motorizing my bicycle. I already have the bike motorized. It can take me at moderate speeds. It needs refinement but the basics work. The problem is this: the engine sits over the rear wheel. Its shaft has a small v-pulley which drives a 21" rim affixed to the wheel as the driven pulley. As clutch there is a small wheel on an arm that moves to tension or loosen the v-belt. I move the the arm with a brake lever on the handlebar. It's just adecuate. The bad thing is that, even when totally loose, the mere weight of the v-belt resting on the driving pulley causes enough friction drag so that pull starting the engine gets very difficult. This engine pull starts very easily; you have to pull very fast, but not hard. With the added drag from the v-belt have I pull and pull very hard and unbelievably the shaft slows down enough to hinder the starting. For this reason also I can't start the engine by pedalling the bike. I really cant pedal that fast. Thus far I have tried to devise a sistem to make the v-belt float over the driving pulley while starting but I'cant come with anything useful. So other than removing the belt while I start the engine and then replacing it (doable but certainly undesirable and unpractical) I can't figure a way to make it work. I thought about a centrifugal clutch, but the ones available have problems:

-The Comet clutch would be ideal, its designed fot high inertia (minibikes,karts) applications but it engages at 1800 rpm, too low for the idle spped of the engine. Since its the non-adjustable type I'm not sure it can be opened and altered to give it higher engagement rpm.

-The chainsaw clutch should engage at the engine +2800 rpm idle speed, but its smaller than the Comet, plus Eric Snow noted that it would overheat while engaging, due to the higher inertia. Besides it would thake somewhat more machining to make it fit.

So with the current setup I'm gonna rip my arm off and keep making the ridicule in front of the whole neighborhood. Unknown if the Comet could be hacked to work. As for the chainsaw clutch, well I dont make the engine propel the bike from still but rather I pedal up to speed and then I engage the clutch and the engine takes over, so perhaps this should at least partly alleviate the overheating problem. What to do?

Thanks in advance,

Camilo