Forum bmwbike.com

This is a bit trivial, but I recently purchased a 1962 R27 and am having a difficult time understanding how to change the transmission and shaft drive oil. Anyone else have this bike and have been through this process? Thank you in advance.

An R27 does not have oil in its drive shaft like a /2 twin. The purpose of such oil is to lube the universal joint, which in the case of the R27 is an open dry plastic disk.

Do the transmission and final drive at the same time. All the plugs take copper crushable washers which compress and seal without the need for much torque - these should be on hand and renewed at each change.

It is preferable to drain the oil when hot, as it flows better and carries more particles out. The drive drain plugs should have magnets in them. At a few thousand miles between changes, it is normal to find sludge and some whiskers on the trans plug, and sludge on the final drive plug.

I would use 40W oil unless you know that your 1962 bike has had its drive train rebuilt since 1968. If the drive train has rebuilt, then the seals will work with 90W hypoid gear oil which provides better lubrication.

Fill the transmission and the final drive up to the lowest thread of their filler hole.

In addition to what Allan has correctly said, the weak spot on these transmissions is at the driveshaft splined coupling between the shaft and pinion.

The male/female coupling has no means of lubrication and the splines can wear alarmingly. Check for any free-play or "clonking".

The only way to lubricate the splines with proper spline grease is to dismantle the unit, which requires special tools (Available from the BMW Club Tool HIre Scheme). Don't be disheartened, it is a straightforward job, but one you need to be aware of.

Enjoy your bike.

Gerry.