Rear wheel reinstallation - tight rotation

millerandy · 2026-03-21T13:58:56-0600

On my '73 850 Commando

I've gone through most of the threads about rear wheel installation, including cush rubbers, spacer fit, top hat spacer, speedo drive, etc. After what I thought would be a simple tire change, I fitted new cush rubbers (old ones were dust), and eventually got the hub back onto the 3 pegs with a lot of effort. I've got the speedo drive and adjacent spacer all fitted, and the axle threaded back into the dummy axle. As I tighten the axle nut, the speedo drive tries to spin with the wheel until I get the nut very tight. Then the speedo drive stays put, but the wheel will only rotate with some extra force. If I back off the nut, the wheel spins ok. I read one thread about the top hat spacer being missing, but nothing beyond the speedo drive was removed and the spacer 06-7629 is still fitted into the speedo drive. Also know that prior to the recent rear wheel removal, everything was working fine. Any help is obviously appreciated.

L.A.B. · 2026-03-21T14:26:21-0600

It's possible you have a bulged speedo drive gearbox?

Post in thread 'Shim on speedometer drive?'

Dec 31, 2018

For the third time, measure the thickness of the speedo drive. It should be no more than 0.825 inches not including the top hat spacer. If it measures more, the center part is bulged out. This bulge causes the inboard side of the drive to encroach on the wheel hub cover.

Apply some heat to the drive housing, and squeeze it to size in a vise using a socket of approx 1.25" outside diameter bridging the hole.

No spacers other than the proper top hat spacer are required. The spread of the swing arms is not a factor.

Slick

millerandy · 2026-03-21T15:37:00-0600

I can pull it and measure, but like I said, everything was working fine before the tire change. Is it possible that the pegs and cush rubbers are just not broken in to the point where the pegs are completely seated into the cush rubber slots?

Torontonian · 2026-03-21T18:05:31-0600

You changed out the cush rubbers for new , Spread the swingarm a tad to fit .

Tornado · 2026-03-21T18:10:12-0600

Torque the axle bolt no more than 45-50 ft-lbs to avoid risk of distorting the speedo drive box. A distorted box usually starts to contact the alu hub cover plate and will self-machine a groove in it...that could be happened in your case. The inboard edge of thew box needs to have a small clearance to the cover plate.

millerandy · 2026-03-21T20:20:16-0600

I'll pull it apart (again) and check the speedo drive dimension. I didn't have a huge problem fitting the speedo and spacer between the hub and swingarm, the problem only arises when I tighten the nut just beyond snug.

L.A.B. · 2026-03-22T03:17:35-0600

Just make sure the speedo drive gearbox isn't touching the hub cover plate.

concours · 2026-03-22T03:43:14-0600

millerandy said:
On my '73 850 Commando

I've gone through most of the threads about rear wheel installation, including cush rubbers, spacer fit, top hat spacer, speedo drive, etc. After what I thought would be a simple tire change, I fitted new cush rubbers (old ones were dust), and eventually got the hub back onto the 3 pegs with a lot of effort. I've got the speedo drive and adjacent spacer all fitted, and the axle threaded back into the dummy axle. As I tighten the axle nut, the speedo drive tries to spin with the wheel until I get the nut very tight. Then the speedo drive stays put, but the wheel will only rotate with some extra force. If I back off the nut, the wheel spins ok. I read one thread about the top hat spacer being missing, but nothing beyond the speedo drive was removed and the spacer 06-7629 is still fitted into the speedo drive. Also know that prior to the recent rear wheel removal, everything was working fine. Any help is obviously appreciated.

What is the wheel bearing status? Had you previously cleaned, inspected, lubed them? How long ago? Or have they been replaced
with sealed bearings? When?

Did you get ALL the crumbs out of the drive tang pockets?

millerandy · 2026-03-22T05:18:51-0600

concours said:
What is the wheel bearing status? Had you previously cleaned, inspected, lubed them? How long ago? Or have they been replaced
with sealed bearings? When?

Did you get ALL the crumbs out of the drive tang pockets?

Yes, did a good wire brush rotary cleaning of both tangs and cush seat.

millerandy · 2026-03-22T05:20:14-0600

concours said:
What is the wheel bearing status? Had you previously cleaned, inspected, lubed them? How long ago? Or have they been replaced
with sealed bearings? When?

Did you get ALL the crumbs out of the drive tang pockets?

Wheel bearings are an unknown but no issues prior to the tire change.

concours · 2026-03-22T05:25:11-0600

millerandy said:
Wheel bearings are an unknown but no issues prior to the tire change.

Let your conscience be your guide.

millerandy · 2026-03-22T07:12:13-0600

L.A.B. said:
It's possible you have a bulged speedo drive gearbox?

Post in thread 'Shim on speedometer drive?'

Dec 31, 2018

For the third time, measure the thickness of the speedo drive. It should be no more than 0.825 inches not including the top hat spacer. If it measures more, the center part is bulged out. This bulge causes the inboard side of the drive to encroach on the wheel hub cover.

Apply some heat to the drive housing, and squeeze it to size in a vise using a socket of approx 1.25" outside diameter bridging the hole.

No spacers other than the proper top hat spacer are required. The spread of the swing arms is not a factor.

Slick

texasSlick

I'm measuring 0.88" to the "shoulder", just out from the bulged center portion. I've squeezed the inner bulge to about 0.90" and now it's nearly flat across. Perhaps I've got the wrong drive, but it worked fine before.

millerandy · 2026-03-22T07:44:23-0600

I rechecked my measurements again and I'm pretty certain it's much closer to 0.90" than 0.825". I put it all back together, and I barely have to use any extra effort to get the wide axle spacer into place between the speedo drive and the swing arm. The wheel spins easier, but definitely not freely and the speedo drive stays put.

L.A.B. · 2026-03-22T07:48:55-0600

millerandy said:
Perhaps I've got the wrong drive

Should be a BG5330/171 which is stamped on the inner ring. If there's clearance as you say then it's not the problem.

Rear wheel reinstallation - tight rotation

MexicoMike · 2026-03-22T11:59:24-0600

If all worked well before you did the work and now it doesn't it's unfortunately pretty safe to say something went awry on reassembly - maybe left out/lost a spacer or something similar?? I don't see how new cush rubbers can cause the problem but an easy check is to remove them/fit the wheel without the rubbers and see if you have the same problem spinning the wheel. The lack of cushions won't hurt anything if spinning the wheel by hand.

Andy Higham · 2026-03-22T14:07:55-0600

Were the dogs inside the drive gear properly engaged with the slots in the hub ?

Rear wheel reinstallation - tight rotation

millerandy

L.A.B.

Moderator

Post in thread 'Shim on speedometer drive?'

millerandy

Torontonian

Tornado

millerandy

L.A.B.

Moderator

concours

millerandy

millerandy

concours

millerandy

Post in thread 'Shim on speedometer drive?'

millerandy

L.A.B.

Moderator

MexicoMike

Andy Higham

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