EL002 ELECTRICAL

My 1960 Viper shredded the dynamo belt - I assume because of age, oil and misalignment (which could only have been slight). Is there some simple method of making sure the alignment and tension is OK?
The old V-belt had "FENNER V495" on it, a type which appears unobtainable now. I got a near replacement which is an "oil-resistant" standard M19 (19") V-belt and it appears to fit OK. - David Royston 28/2/2001

To get the belt adjusted correctly, you put a straight edge on the four edges of the pulleys, if it touches all four then the belt is aligned; and the tension should be 'no slack but not tight' - a firm finger push at the mid-point would move it about 10mm. But you can only check these after tightening the single clamp bolt.... so you soon learn to make allowances before tightening it - mainly more slack, because tightening the clamp levers the dynamo up (in fact I push the dynamo up as I tighten to make sure it does).
A modern V-belt can't be used as a replacement on the original pulleys - or rather, it can, but there will be a constant 'screaming' because it has a different angle V so is only making point contact.
The right belt nowadays is labelled "Classic" or some such.
Try measuring the V angles of your new & old belts, assuming you can find an unmangled bit, or the pulleys.
By far the best solution is to fit the club's toothed belt conversion! (Assuming you have the standard taper fit dynamo pulley or can accurately machine the new pulley parallel, with a keyway, if not).
I have three fitted, and they are superb. - TW 28/2/2001