Boxerworks.com

Hello, I recently acquired a 1972 r60/5 and I'm going through the bike fixing things as I go along. It has 48k miles on it but overall it's in good condition.

I've noticed a bit of a slop in the drive line. It's especially noticeable when I roll the bike backwards with the clutch in and then release the clutch. There's a bit of a clunk when the clutch engages and the driveline slack is taken up. Today I took off the rear wheel to grease the output shaft and wheel splines and found there is a bit of rotational play in the output shaft of the final drive. I'd estimate about 1mm of play, maybe slightly more. Below is a video showing amount of movement. There's no side to side or axial play that I can feel.

Is this too much rotational backlash? Is a final drive rebuild in my future?

I would just check it again after another 48,0000 miles.

That looks fine to me... don't forget that is the accumulated backlash from the final drive, the drive shaft bell joint and the gearbox so, (not to mention the hooke joint in the drive shaft... which really shouldn't have any detectable play). Even if there were excessive play it wouldn't necessarily be the final drive at fault.

Rob

Thanks all. I'm not putting much pressure on the output shaft so I don't think I'm actually turning the pinion get much at all. It sounds like it's fine though, which is good to hear.

My plan is to keep on riding it.

FYI -
With the wheel installed, check the driveline backlash with the transmission in first gear.
You should be able to 'klunk' the wheel maybe an inch or so back and forth.
In fifth (top) gear it will be 2 to 3 times that amount.
This is normal for any manual transmission bike or car.

As far as the odd klunking noise from the drivetrain when rolling the bike around...
Unless it's really loud and consistently repeatable, don't worry about it.

When I worked at a BMW shop in the '70's, we'd roll over a dozen or so airheads out in the morning and back in at night.
The odd one might 'klunk' a bit on the way out, another might 'klunk' a bit going back in.
It was considered normal and never seemed to have any long term repercussions.