I had a Vincent Shadow with a Steib single seater sports sidecar for 30 years and this was obviously chain drive, (Reynolds 5/8" x 3/8" Roller chain).
Despite the engine only putting out approx. 55 bhp, if you were lucky, with spirited driving the chain would end up looking like a piece of knotted string after about 4000 miles.
This was despite regularly cleaning it and soaking it in "Linklife" (moly loaded grease specifically for chains) on the gas cooker when the wife was out.
The teeth on the rear sprocket also become badly hooked after quite a short time.
I think for a chain final drive to be more reliable than the existing belt set up it would have to be a duplex chain fully enclosed in a chain case to keep the lubricant in and the dirt out.
I think we are all now stuck with the belt set up that we have and the way to improve it would be either:-
a) A steel rear pulley which we are told the factory are currently looking into. It cannot come quick enough IMHO.
or
b) the polyurethane toothed pulleys from the states as featured on another thread.
