I use Gates belts in the Morini as a lot of people do in the owners club. The only issue with the Morini is the crankshaft and cam wheels are marked A, B or C at the factory when the engines are built. Morini recommend you buy the specific belt for your engine and marked accordingly. The maximum slack is 6mm on its longest stretch (not very long considering the crank pulley is virtually directly below the cam pulley). It seems Moto Morini bought belts from different manufacturers back in the day and therefore there were tolerance differences between the manufacturers (remember we are talking 70’s manufacturing technology). Morini would then try different belts on every engine to determine which belt provided the 6mm tolerance and marked the pully to suit with an A, B or C. This is why Morini OEM belts are four times the price of a Gates belt or any other manufacturer. I bought a number of Gates belts at different times and fitted them by trial and error to find the one with the correct tolerance. It is surprising the variance of what are the same spec of belt by the same manufacturer but over different batches.
Toothed belt manufacturing has moved on dramatically over the past 20 years with new technology making them much longer lasting and resistant to heat and oil (although I'm not sure if anyone running a Ford Eco engine would fully agree!).
