Cam Chain Idler sprockets

[rpeters]

Can someone clarify please, are the top idler and two lower sprockets all interchangeable. Ie will 78 z1000 fit an 80 Mk2 being that the Mk2 has 16/32 cam sprockets, will the pitch be different?
Thanks
Rob

[DeadZedDave]

Hi Rob, I believe the idler sprockets are all the same / interchangeable for all of the 1015 motors (and most of the 903's) HOWEVER the A3/A4's have a different top idler support bracket which has a different shape to fit under the Mk2 shape cam cover AND more importantly, the Mk2 shape support has a different centre height for the top idler. The difference is small but it's worth checking the cam timing after assembly if your going to mix and match parts. Also, the Mk2 top idler assembly is riveted together so a bit more work to swap the actual sprocket. E1/E2/ST/Shaft also uses Mk2 gear. Some early USA A3/Ltd motors actually have A2 type cranks/cams etc. Hope this helps !

[zed1015]

All the idler sprockets are the same pitch and tooth count (17t) .

[rpeters]

Thanks, I have a few top idler assemblies, I think the A4 one is cranked over and not straight like the others and rivetted like you say. It has some side play but no vertical play so not sure whether to source a new one or not

[DeadZedDave]

A little bit of side play is normal - I think ! I would expect the earlier type ones to be about the same. I'm happy to be corrected but if you have no vertical play I think it'll be fine. If theres still a question, please let me know and I'll see if I can get one out and check for side play. So far as I recall, the "rivet" or bolt should clamp the centre "bush" of the sprocket bearing tight but the sprocket itself will have some side to side clearance.

[kev edwards]

A little side play is completely normal.