belt drive

A bit of excitement today,,,,,
After altering the carb clip to mid position, mk2a , pw3 , 260 main jet , i took it out for a spirited test ride .......
going along the a38 here in Devon at about 6300 rpm up a gradient towards Ashburton, [if you know the area] i lost drive , no nasty mechanical noises so i suspected my Norvil belt drive,,, got rescued by the AA and found indeed the belt had shredded its teeth, luckily no apparent damage , this belt was only 4 years old or so, any one had similar with said belt ?
Colin

Belt drives do have their moments resulting in spare belts being carried.

Make sure the belt is not over tight when cold. The drum expands quite a bit when the clutch heats up causing a too tight belt to loose all its teeth or shred.

I will double check this time ,I do not want to lash out £50.00 too often for a belt ,,,,,
this must be a generic item and not produced solely for Norvil,,,,,

colin davie said:

I will double check this time ,I do not want to lash out £50.00 too often for a belt ,,,,,
this must be a generic item and not produced solely for Norvil,,,,,

Click to expand...

50 pounds is a fair price. They go up from there.

The Gates belt that Norvil use is available from engineering supply businesses. Usually cheaper than Norvil sell them. If you search online you should find a few places selling them.

colin davie said:

I will double check this time ,I do not want to lash out £50.00 too often for a belt ,,,,,
this must be a generic item and not produced solely for Norvil,,,,,

Click to expand...

I've been running a norvil belt drive for around 25 years
I replaced the belt a few years ago because it was quite old
But there's visibly nothing wrong with it
There is some wear to the anodising on the pulleys but it's still acceptable
I had to make a new front belt guide when I fitted an Alton starter and drove it off the front pulley (Yves conversion)instead of the alternator keyway but never a problem with the belt
You need to spend a fair bit of time adjusting the tracking and tension

Take a good look at the teeth on both the clutch & the front pulley. Norvil claim their pulleys are hard anodised, but that wasn't the case on mine. Once the anodising has worn through the aluminium start to suffer & then damages the belt.

Yesterday was quite warm. So the lump was likely in full expansion mode. You have to check the belt when completely hot. You may well
be surprised how much they tighten up. Yes, when cold they can be
rather loose and the back will rub against the alternator studs on some.
Is there any indication of this happening? It is pretty obvious as there is
black belt dust.

The last time the primary was apart was when Norman White took the motor out to fit a pw3 cam....
Not pointing any fingers at this but i dont think i ever checked it since, I will have to keep an eye on it now.
Thanks all.......

I fitted a norvil belt drive kit for my e/s mk3 around 15 to 20 years ago and as I wasn't happy with tension I phoned "Les" on his between 4&5 pm help line. Send in the exact size between the centres of drive and gearbox shafts. Did that using an industrial large vernier gauge ! Had to buy new pulleys which would solve the problem. I still wasn't happy with the belt seeming a little slack. Drive it I was told ! After 15 miles the smell of burning rubber and the fact my gear lever was bouncing around said things weren't well. Belt had disintegrated into shredded rubber confetti and both pulleys toothless !! I must have made a mistake in my measurements! No refund ! Very expensive rubbish. Changed to RGM kit and no problem with the belt since ! P.S I have a brand new Norvil mk3 seat free except for postage, bought also 18 years ago at only about £100 . Bargain! No danger of fitting my bike. I have probably got a faulty Italian frame according to " Les ". I wouldn't buy a washer from him ! Rubbish parts and afterservice from my experience! Do I sound bitter ?