Tach for ‘62 R69S #656872 ?

[thornattyr69s]

New forum member here but longtime /2 owner & many parts from Vech, Max et al.
I’m looking at 2 questions for my bike:
1. There are mechanical tachs & parts available from both Max BMW (internal drive) and a custom machined source (outside drive).
Yes, I know I don’t need one but I’d like advice if I decide to do it.
2. My stock ‘62 has a non-bulge chest cover. Do all chest covers ‘61 - ‘69 fit the same bolt pattern?
Thanks guys!

[Flx48]

Hi Thor-
I'm seeing only one question, though I'm probably not totally awake yet...

Do all chest covers ‘61 - ‘69 fit the same bolt pattern?

Gather you are replacing the gen cover for one reason or another.
All the Earles fork bikes have the same bolt pattern for mounting the gen cover.
The earlier bikes had M6/M6 mounting studs, while later had M6/M8, the difference being at the gear cover end and not the gen cover end, so you should be good.
What you may want to pay attention to is the bulges.
The '61 only gen cover had the mini bulge for the cam drive tach mount.
Don't recall if there were several iterations of the damper bulge or not, but there were several sizes of fork brace flats, so you may want to pay attention to: damper bulge vs fork flat clearance as you look at different covers.
If you don't have a damper then you don't need a bulge, though the later bulge covers came with an outline of the tach drive hole location on the inside.
Otherwise a '61 gen cover, or a Hoske tach drive mount plate on your old gen cover, would seem most desirable if wanting to add a tach.
Best-
George

[schrader7032]

On Duane Ausherman's site he says there are three versions of the fork cross brace. In '55, the cross section was round. In '63 with the addition of the harmonic balancer, they flattened the brace to clear the small bump in the engine cover. In about '66-67, they flattened the brace again and it is noticeably flatter.

He also says that the bolts changed four times over the years - slotted, 14mm, 13mm, and 10mm.

Beemer Garage shows the service bulletin with the parts needed for a tachometer installation:

http://www.beemergarage.com/documents/201.pdf

Here's another bulletin:

http://www.beemergarage.com/documents/250.pdf

[Flx48]

For clarity's sake, I was referencing the two sizes of studs mounted in the gear cover that the gen cover attaches to; Duane was probably referencing the various heads on the gen cover's captive nuts that attach to those studs.
Best-
George