Rear wheel bearing spacer

Hi Just rebuilding my Commando rear wheel (74 850) Using all new parts as I need to quickly swap the old drum + sprocket over since the bike is essential for day to day usage.

The problem I have is that the rear axle binds in the dummy axle bearing spacer, anyone else found this or does anyone know what the rear axles diameter is +/- tolerance. Or the ID of the dummy axle bearing spacer +/- tolerance a big ask but this forum is normally pretty good for even the most obscure requests...

Regards Paukl

Strangely my rear wheel is off at the moment to drill & pin the speedo drive. Diameter of the axle is 0.562" and over the thread 0.553". The axle is a very snug fit where it enters the dummy axle and best I can measure is 0.563/0.564" bore. What are the dimensions on your old axle?

I'm not sure how the 850 rear wheel goes together, but on my 69 750, i originally installed the rear hub spacer backwards (with the long end of the spacer in the double row bearing) and every time I tightened up the rear wheel, everything would bind up. I reversed the bearing spacer and all was fine. The longer end of the spacer goes into and through the single row bearing.

Dave
69s

Keith1069 said:

Strangely my rear wheel is off at the moment to drill & pin the speedo drive. Diameter of the axle is 0.562" and over the thread 0.553". The axle is a very snug fit where it enters the dummy axle and best I can measure is 0.563/0.564" bore. What are the dimensions on your old axle?

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Thanks for the info sadly I have had to put all the old rear hub back together since the new sprocket/brake drum assembly was 5mm thicker!! (Measured from surface to surface not including the wheel mounting points $%£"**!!!!)Anyway will use the info when the replacement sprocket/brake drum assembly arrives and I do the whole process again....:-( Will let you know when I dismantle it all again.

Thanks I knew I would get an answer

It might be that the stepped sleeve that protrudes on the wheel side of the hub is interfering with the wheel axle, if its been damaged. This sucker has to be gripped in a vice while the hub is smacked off it. Crude, yes but thats how it is. Try having a good look at the lip and bore of it. May need a careful filing.

If the inserted photo comes shows up OK, the parts on the left are the wheel side bits and the bits on the right are the hub side. There may be more spacer shims on the hub side as required by individual assembly. The bearing should be a sealed double row ball.

Mick

Since everything thing is apart, if you can take a picture with everything in order?

ML said:

It might be that the stepped sleeve that protrudes on the wheel side of the hub is interfering with the wheel axle, if its been damaged. This sucker has to be gripped in a vice while the hub is smacked off it. Crude, yes but thats how it is. Try having a good look at the lip and bore of it. May need a careful filing.

If the inserted photo comes shows up OK, the parts on the left are the wheel side bits and the bits on the right are the hub side. There may be more spacer shims on the hub side as required by individual assembly. The bearing should be a sealed double row ball.

Mick

Click to expand...

Hi thanks for all the info to clear matters up I had purchased all new parts to rebuild the sprocket/drum assembly as my bike has to be used every day. So I had a new sprocket/drum and new dummy axle, new bearing, new circlip, new washer, (goes in between bearing and felt seal) new felt seal and new felt seal retaining ring. Also a new bearing spacer. The only pieces I was goint to reuse were the axle (ss) and the left hand axle bolt (ss) and both washers (ss). So built up the sprocket drum assembly withall the required pieces than befor fitting attempted to push axle through to check fit and it would not go past the threaded section. At this point I removed the old bearing spacer fitted that then replaced the wheel. So now its 1.00pm in the morning so very rashly ran a quick eye down the sprockets to check for alignment seemed OK .....I must have been tired because it was certainly not drove for about a mile then heard noises ....not good ...stopped the bike looked around it with a torch and found about every 5th to 7th link fracturing around the pin. So rode back at about 5mph removed everything put back old sprocket/drum which only required putting the old bearing spacer back cw washer felt seal and seal retainer. But just before put both drums on my bench when I noticed the disparity in overall size, excluding the paddles. It was 5mm (The new drum was 5mm wider....)..hope that clarifies what I did. (1974 850 MK II)

Cheers Paul

swooshdave said:

Since everything thing is apart, if you can take a picture with everything in order?

Click to expand...

Hoping new sprocket/brake drum arrives tommorow so will be redoing the whole process will measure everything as I go including the sprocket/brake drum width which I assumed would be OK.......:-( Will hopefully be able to give out some useful info...

Regards Paul

Paul,
Thats a worry that your NEW hub was 5mm wider! Where did you get this part from? I'm utterly pissed off with dud aftermarket crap making me do jobs twice. Yet again I've been dudded this time with a 750 exhaust header pipes....right hand is an early 750 tuck in bend early 750 and the left is late model bend. Its not a matched pair. The vendor..another "E shop" insists this is stock and ALL Commandos had this!
Seems we have to measure every dimension and probably do a hardness and tensile test before we fit the stuff! Just wish the Mafia was into Nortons that'd sort out some of these jerks.

Mick

ML said:

Paul,
Thats a worry that your NEW hub was 5mm wider! Where did you get this part from? I'm utterly pissed off with dud aftermarket crap making me do jobs twice. Yet again I've been dudded this time with a 750 exhaust header pipes....right hand is an early 750 tuck in bend early 750 and the left is late model bend. Its not a matched pair. The vendor..another "E shop" insists this is stock and ALL Commandos had this!
Seems we have to measure every dimension and probably do a hardness and tensile test before we fit the stuff! Just wish the Mafia was into Nortons that'd sort out some of these jerks.

Mick

Click to expand...

Hi this was a private piurchase through Old Bike Mart so hoping the other coming from my usual supplier is OK but will chaeck it out guess I thought that a part like this would be correct in terms of size.

Paul

For anyone interested in the saga of my rear sprocket/drum replacement I will follow up with a couple of postings with what I find with the parts I had purchased from a couple of sources. Recieved the sprocket/drum component today part : 062764. The width of the drum/sprocket is 45.15 +/- .02 mm The previous one that did not fit is not only oversize but has significant differences when measured around the drum +/-3 mm.

The other item I have checked was the brake drum bearing spacer a genuine Norton spare which the axle would not fit through It has an ID of 0.559" which does not match 0.563" to 0.564" given by Keith1069 also his axle came to 0.562" in diameter, so his axle would not fit my bearing spacer and tommorow the wheel will be off and my axle measured just to get everything nailed down. I am surprised as this bearing spacer was a genuine Norton spare. :- (

plj850 said:

For anyone interested in the saga of my rear sprocket/drum replacement I will follow up with a couple of postings with what I find with the parts I had purchased from a couple of sources. Recieved the sprocket/drum component today part : 062764. The width of the drum/sprocket is 45.15 +/- .02 mm The previous one that did not fit is not only oversize but has significant differences when measured around the drum +/-3 mm.

The other item I have checked was the brake drum bearing spacer a genuine Norton spare which the axle would not fit through It has an ID of 0.559" which does not match 0.563" to 0.564" given by Keith1069 also his axle came to 0.562" in diameter, so his axle would not fit my bearing spacer and tommorow the wheel will be off and my axle measured just to get everything nailed down. I am surprised as this bearing spacer was a genuine Norton spare. :- (

Click to expand...

Please post exactly where you are getting the bogus parts from.

The other item I have checked was the brake drum bearing spacer a genuine Norton spare which the axle would not fit through It has an ID of 0.559" which does not match 0.563" to 0.564" given by Keith1069 also his axle came to 0.562" in diameter, so his axle would not fit my bearing spacer

Click to expand...

I measured with Clarke digi vernier so it's not a calibrated tool. However the major dia of the axle is a very snug fit in the dummy axle/spacer. This was replated 11 years ago and most of that zinc is worn off. Also I did run a die over the axle threads. Mine is back together now but didn't measure the drum as mine has 3mm off for a 520 conversion. This was a replacement part from Andover in 02 after I stripped 9 teeth off the original somehow!! It fitted very well.

plj850 said:

ML said:

Paul,
Thats a worry that your NEW hub was 5mm wider! Where did you get this part from? I'm utterly pissed off with dud aftermarket crap making me do jobs twice. Yet again I've been dudded this time with a 750 exhaust header pipes....right hand is an early 750 tuck in bend early 750 and the left is late model bend. Its not a matched pair. The vendor..another "E shop" insists this is stock and ALL Commandos had this!
Seems we have to measure every dimension and probably do a hardness and tensile test before we fit the stuff! Just wish the Mafia was into Nortons that'd sort out some of these jerks.

Mick

Click to expand...

Hi this was a private piurchase through Old Bike Mart so hoping the other coming from my usual supplier is OK but will chaeck it out guess I thought that a part like this would be correct in terms of size.

Paul

Click to expand...

Hi as far as info about the parts will hold fire until have checked the axle diameter but the bearing spacer was a "Genuine Norton Part" is that a good enough clue the sprocket/drum was from Old Bike Mart a private sale...sold as a new Norton Commando Sprocket/Drum but now I have closely examined it is sub-standard in many ways so that is my problem as they say caveat emptor for those who dont do latin this translates as "Buyer Beware" as for the bearing spacer I will contact the seller and discuss the problem....

Measured axle diameter it is .563" so no way it was going to fit through a bearing spacer with ID of 0.559" returned spacer today and see what vendor says about it....

You did the right thing by returning but I would probably have run a 9/16 drill through it. Why were you replacing it, was there some other wear? Did the axle thread into the dummy ok or was that undersize? I've probably been lucky and despite all the parts bought from Andover or Norvil I've rarely had a problem. The only issues have been a gearbox clutch assy ring which was oversize and RGM machined mushroom tappets adjusters, also oversize.

Keith1069 said:

You did the right thing by returning but I would probably have run a 9/16 drill through it. Why were you replacing it, was there some other wear? Did the axle thread into the dummy ok or was that undersize? I've probably been lucky and despite all the parts bought from Andover or Norvil I've rarely had a problem. The only issues have been a gearbox clutch assy ring which was oversize and RGM machined mushroom tappets adjusters, also oversize.

Click to expand...

Hi was replacing everything that would be required when replacing the rear drum which had been scored for about 2 years, and the MOT guy although happy about not expecting the rear brake to be great (He owns a Commando) said next time it would need to be a tad better!!.. so since I need my Commando for work I decideded to make sure there would be no holdup in fitting the new drum, so bought all the pieces to build up the hub with bearing and circlip and dummy axle etc.
(You know what happens dismantle the hub and discover the bearing spacer wont budge or the circlip pings off the end of your circlip pliers and dissapears into the nether regions of the garage never to be seen againetc etc. :roll )I also buy from RGM and Andover and have done so for years with only 2 problems this bearing spacer and a stainless steel rear wheel nut with a tapering thread.Axle passed into dummy fine.