I removed the distributer drive (Pt No: 12G4499 (MOSS)) from a 948cc engine this morning and I have never seen such wear to the teeth. About 1mm was gone from the root of all of the teeth and the top of the gear was a very sharp knife edge.
The cam shaft did not seem to be too bad but the distributer must have been all over the place.
An examination of the condition of the shaft teeth may be in order if the timing is all over the place and no other cause is obvious.
Phil
Distributer drive shaft.
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Re: Distributer drive shaft.
I experienced exactly the same when I rebuilt my 948 with a Swiftune SW5-07 cam and various other components. It took me a while to figure out the cause of the increasingly rough running. Unfortunately by the time I did figure it out, the new big end and main bearings were ruined from the huge amount of swarf generated. A replacement (also new) cam caused the same issue - Swiftune blamed ‘harmonics’ and said the cam gear wouldn’t be at fault. Fitting a NOS BL cam cured the problem and all has been well for the past 10 years... I wondered whether the Kent billet blank used as the basis for the cam was the issue, but had no way to measure the helical gear to answer that question unequivocally.