Achsantrieb

[Scott A.]

'61 R27 now with 140 miles on a refreshed engine.
The 25/6 final drive makes 4th gear an interesting accessory, maybe good for accelerating downhill.

I may soon have the opportunity to install a 27/6 gear-set in the housing.

It would be my first time adjusting a final drive so I'm studying the Reparaturanleitung and have also found this entry:
http://bmw-einzylinder.de/forum/index.php?topic=12539.msg167331;topicseen#msg167331

Question is: what other good entries or other resources are available for better understanding?

I've had some success rebuilding the transmission so perhaps I can give this a try.

[Scott A.]

[Rütz]

I would recommend these threads:
http://bmw-einzylinder.de/forum/index.php?topic=2530.msg35366#msg35366 (R26 / R27)
http://bmw-einzylinder.de/forum/index.php?topic=7633.msg99091#msg99091 (mostly R25/3)

The two most important points (inmho):
1. Mounting and dismounting of bearings, lid, axial seal ring in the lid and(!) the screwing ring of the pinion bearing only while casing/lid are hot (~100 °C )!
2. "Die spotting" is essential, when choosing the right shims for the pinion bearings. The engraved numbers (crown wheel) are only a "coarse hint".

[isie]

strange

'61 R27 now with 140 miles on a refreshed engine.
The 25/6 final drive makes 4th gear an interesting accessory, maybe good for accelerating downhill.

I may soon have the opportunity to install a 27/6 gear-set in the housing.

It would be my first time adjusting a final drive so I'm studying the Reparaturanleitung and have also found this entry:
http://bmw-einzylinder.de/forum/index.php?topic=12539.msg167331;topicseen#msg167331

Question is: what other good entries or other resources are available for better understanding?

I've had some success rebuilding the transmission so perhaps I can give this a try.

[Scott A.]

strange

how so?
... that the engine isn't developing enough horsepower to utilize 4th gear?

could be still running in.
I haven't actually tried any high-speed run, but my impression is the 27/6 gearing would be more suitable.

Even getting underway in 1st would require less clutch.
(The lightened flywheel providing less inertia for this purpose)

[isie]

strange way to communicate

[Scott A.]

strange way to communicate

yes.

...life is strange