Topic: Works or 970 kit cam specs?

[gschuld]

I’ve seen various reports on cam details for the Works bikes.  3 different power levels were quoted and it was suggested the differences were in the cams.  Does anyone have the specs for these cams or even the intake and exhaust lift figures?

Same question for the 970 cam.  Was there a 971 cam?  What were the specific markings on the 970 cams?  Were they CWC billet blank cams or something else?

George

[napoleonb]

I didn't find a 971 cam in my K5 kit partslist (aug 1974) so I don't think there was.
In the sports list the timing is noted as
20 20 with lift in 9.0mm
45 45 with lift ex 8.5mm

Funny thing is there is a hand written spec in the same list which states:
20 21
47 45

In the CR750 price list from march 1972 I've got there is this mention (same camshaft number):
Valve timing changed in20/45, ex 20/45 valve lift changed in 9.5mm, ex 8.5mm.

So I think this answers some of your 970/971 questions, I've got no idea of the works machines.

[gschuld]

Add the images below to the list and you can see why there is some confusion.  It seems every time I locate reported 970 cam specs, the numbers are different.  I’m having a hard time trying to figure out what is correct, how many possible different cam grinds were available, etc.

I know Steve McLaughln used a custom grind cam he helped develop on his successful CR racer.

Does anyone know what blanks were used in the 970 cams?

George

[gschuld]

From the 1970 Cycle Magazine article.

Same 20/45 45/20 timing figures but .334” (8.4mm) intake and exhaust lift.

George

[gschuld]

So so far

We have

8.4/8.4 lift
8.5/8.5 lift
9.0/8.5 lift
9.5/8.5 lift

All seem to have the 20/45 45/20 timing

George