Here is the problem with the garelli starter clutch. Unlike most wet clutches that use a friction plate to engage the clutch , the garelli uses an expanding rubber insert that fits inside the clutch drum. This was a good Idea at the time because the rubber insert did not really wear and was replacable for about $4.50 . Of course they are no longer available and fetch a slightly higher price now. The problem is that after years of sitting in the engine they become oil impregnated and begin to swell causing the starter clutch to drag. Some times you can simply back off on the cable adjustment to keep this from happening. Something that I have found to work occasionally is to take the rubber insert out. Dry it off using brake cleaner and then putting it in the freezer for a few days. When it defrosts it will be slightly smaller. Of course before you do any of this check to make sure that the cable is adjusted properly and that the cable is in good shape and not hanging up causing the starter clutch to be engaged all of the time. In a worse case scenario we do have one of those inserts left in stock. But try to salvage yours first.
The Moped WareHouse