RGM belt wheel alignment issue.

fiatfan · 2026-03-24T05:22:30-0600

850 engine and a "bitsa" gearbox, all restored, all in it´s place. When I use a straight edge on the clutch wheel and measure the distance from that in to the outer edge of the front belt wheel, it turns out that the clutch wheel is 1mm further out (0.04"). I don´t have any schims behind the clutch, just the spacer. There is an 11mm edge on the clutch wheel outside the teeth, but there is 12mm from the straight edge to the outer edge on the front wheel teeth. How can this effect the belt, if it at all will?

concours · 2026-03-24T05:27:08-0600

fiatfan said:
850 engine and a "bitsa" gearbox, all restored, all in it´s place. When I use a straight edge on the clutch wheel and measure the distance from that in to the outer edge of the front belt wheel, it turns out that the clutch wheel is 1mm further out (0.04"). I don´t have any schims behind the clutch, just the spacer. There is an 11mm edge on the clutch wheel outside the teeth, but there is 12mm from the straight edge to the outer edge on the front wheel teeth. How can this effect the belt, if it at all will?

Pics please.
Where are the belt guides located on the sprockets?

baz · 2026-03-24T07:45:50-0600

fiatfan said:
850 engine and a "bitsa" gearbox, all restored, all in it´s place. When I use a straight edge on the clutch wheel and measure the distance from that in to the outer edge of the front belt wheel, it turns out that the clutch wheel is 1mm further out (0.04"). I don´t have any schims behind the clutch, just the spacer. There is an 11mm edge on the clutch wheel outside the teeth, but there is 12mm from the straight edge to the outer edge on the front wheel teeth. How can this effect the belt, if it at all will?

The front pulley has the belt guides there's none on the clutch
You need to spend some time with the double adjuster on the gear box getting the belt to run true
As long as the full belt is on the clutch and it doesn't wander you are good to go

Metisse11 · 2026-03-24T14:10:05-0600

I run a couple of RGM belts on two of my Commando's and always set up the alignment with the inner primary chaincase removed and also us a double sided tensioner.

RGM belt wheel alignment issue.

fiatfan

concours

baz

Metisse11

Similar threads