When working on getting more go out of an M40 moby I came across an unexpected problem.
The drive sprocket that sits behind the drive pulley was way to big for my intended purpose
having 13 teeth. The only way i could get the variator to pull the bike up a hill was to drop to a
smaller sprocket. That was where the problem was,
there wasn't an easy fix as, being40+ years old certain parts tend to be in short supply.
The answer was to buy a nice aluminium pulley which had a smaller 11 tooth sprocket fitted. The
drive sprocket on these pulleys is a Peugeot pattern part so fits solid with the use of grub screws
and clamps to the rear of the pulley. It also means that the pedals can't be used without turning
the engine over, there's no turn-screw to disconnect the engine. There are several types of pulley
easily available on French sites and most (all?) are the same diameter as the standard tin pulleys
fitted to most mobys. Fitting is just a case of sliding the old pulley foo and, using the appropriate
spacers, sliding the new pulley on, easy.
Finally, they do look good when used with footrests, dropped bars...