Help Required-Rear Hub Rebuild!!

Hello everyone. I'm a newbie to Access Norton and this is my first post. Thank you for letting me join.

I hope a member or members can help me out with something I've been tearing my hair out with.

I've been the owner of a Les Emery Norvil Commando in mainly MK11A spec for a few years which I acquired on Ebay. It was built in 2006 and the previous first owner had only done 250 miles. It's used by me on high days and holidays, only showing around 4000 on the clock now.

I took it out last week and suffered a rear wheel blow out. No real dramas but obviously time for new tyres and tubes etc.

I pulled the rear wheel off for the first time, and when doing so noticed that the lip of the inner race of the double row bearing at the brake drum side of the hub had sheared off in several places. There was no major swarf around but the bearing was gritty and clearly needed replacing. I'd be forgiven for thinking that it had originally been driven into place using the inner race when built, but I'm sure it wasn't!! However, it's difficult to imagine what force could have caused that.

I'd mention here that the rear hub used by Norvil on this build is the Pre 1971, brake drum type. No cush drive. The hub being attached to the brake drum on 3 studs with long nuts.

Removal of the old bearings was the easiest on any bike I've done over the years, using a combination of front and rear wheel spindles as described in the shop manual, Haynes, Norman White etc. Replacing with new bearings obtained from Andover Norton with a little heat was almost as simple as well. I marked up the bearing tube to confirm its orientation, ie. long shoulder to the speedometer side of the hub, and short shoulder to the brake side of the hub. The new bearing measurements were identical to the old ones removed.

All the re-assembly was done in the correct order per the workshop manuals.

I bolted the completed wheel assembly onto the brake drum. The hub bolted flush and square onto the brake drum on the 3 studs and their shoulders. Speedometer gearbox fitted over the single row bearing lock ring etc, with everything ready to accept the rear spindle - except now the rear spindle spacer appeared to have gained 7mm overnight! There was no way the spacer was going to fit in without seriously trying to spread the swinging arm to get it in, so something was clearly wrong.

Nothing had been touched by me on the brake drum side of the swinging arm, ie. that was left in place, tight, with chain still attached etc when the wheel was removed. Just as it had left Norvil.

My thoughts immediately turned to perhaps being tired I'd actually put the bearing spacer tube in the wrong way around, so today I dismantled the hub again, taking the new bearings out, and no, I had put the spacer in the correct way. I put it all together properly again, this time with a friend sense checking me and the same problem as before. The wheel spacer won't fit in after the wheel is bolted onto the brake drum. We repeated all the steps again and same issue happened.

I'm totally beat. I am even considering turning the bearing spacer tube the other way around, contrary to what all the manuals say, but I'm sure 3 different workshop manuals can't be wrong over the bearing tube orientation, just in case, as a longshot (again I doubt it) that Norvil assembled the bearing spacer tube the wrong way around, and then used a non standard axle spacer to fit.

Can anyone point me in the right direction as I've run out of ideas, Help please!!

PS. Before I order a new axle spacer to prove/disprove my possible assertion that Norvil used a custom length, does anyone out there know how long the standard spacer between the speedo gearbox and the swingarm is?

Are the tangs on the speedo gearbox located in the hub slots?
If not, that could account for about 5mm “growth”.

Simon Stephenson said:

I marked up the bearing tube to confirm its orientation, ie. long shoulder to the speedometer side of the hub, and short shoulder to the brake side of the hub.

Click to expand...

As far as I'm aware that's the wrong way for the bolt-up hub, (but correct for the later hub) the long shoulder should be on the left (brake side) as the double bearing is in the hub, not the drum and that's what the Clymer manual says, below. Note that the pre-'71 and post-'71 bearing spacers are different.
"On 1970 and earlier..."

DougC said:

Are the tangs on the speedo gearbox located in the hub slots?
If not, that could account for about 5mm “growth”.

Click to expand...

Thanks for your feedback Doug. The tangs are properly located so I don't think that is the issue.

L.A.B. said:

As far as I'm aware that's the wrong way for the bolt-up hub, (but correct for the later hub) the long shoulder should be on the left (brake side) as the double bearing is in the hub, not the drum and that's what the Clymer manual says, below. Note that the pre-'71 and post-'71 bearing spacers are different.
"On 1970 and earlier..."

Click to expand...

Hi,

Thanks for your feedback. The Clymer manual is the only one I don't have, but all the others say put the longer shoulder on the right side. (I couldn't remember how it came out but marked up the orientation advised in my manuals with a sharpie so I didn't get it wrong putting it back in!!) However, what you (and Clymer) have suggested, was what I was going try next and thank you for confirming that that might not be a stupid idea. My Commando is clearly a bit of a bitsa. It's an 850 but uses earlier 750 components on the back end! It has Norvil twin discs on the front. That was another story. I couldn't take the front wheel out without taking the callipers off because the wheel rim wouldn't clear them. Trouble was, unlike a modern bike where the calliper bolts screw into the calliper housing, I couldn't get a spanner to the nuts that tighten the calliper bolts because they are shrouded by the discs themselves, so you have a ludicrous position where you fit the wheel under the mudguard, then the callipers, with just sufficient space to tighten the nuts, then offer the wheel, spacers and spindle up to the forks. Nowt's ever simple!!

Thanks again and I'll let you know how I get on over the next few days.

Great to see another new member on board
Whereabouts in the UK are you based?
On the subject of front wheel removal, have you considered removing the mudguard so you can swivel the sliders to allow the calipers to clear the wheel?

FWIW, I have to routinely "pry" the swingarm "open" to fit the spacer in place when reinstalling the rear wheel on my '73 850. My old 750 was the same; I thought it was normal!

When you read accounts from factory workers about assembling these bikes, nothing seems too surprising. Some years back a former factory worker stated that they sometimes would have to jump up and down on a frame to get it to align with relevant parts.!!!

B+Bogus said:

Great to see another new member on board
Whereabouts in the UK are you based?
On the subject of front wheel removal, have you considered removing the mudguard so you can swivel the sliders to allow the calipers to clear the wheel?

Click to expand...

Hello. Thank you for your response. You know, sometimes the simplest things stare you in the face and it takes a fresh pair of eyes to point them out! Of course that would work. In my defence I was probably so hacked off with the rear wheel issue, and, as I'm also in the middle of building a new house, where I'm living at the moment have extremely limited room to move around the bike. I'm based in North Tyneside, soon to move into the Northumberland National Park, where I've specced some decent workshop space! Thanks again and best wishes.

MexicoMike said:

FWIW, I have to routinely "pry" the swingarm "open" to fit the spacer in place when reinstalling the rear wheel on my '73 850. My old 750 was the same; I thought it was normal!

When you read accounts from factory workers about assembling these bikes, nothing seems too surprising. Some years back a former factory worker stated that they sometimes would have to jump up and down on a frame to get it to align with relevant parts.!!!

Click to expand...

Mike, good to hear from you and thanks.
I hear what you say and I've had similar problems with other bikes before, but not to that extent, and if my memory serves me, when it came apart it literally twisted out with no spring effect on the swing arm.
I'm going to try putting the bearing spacer in the other way around as described by another member here and see what happens. I have another set of new bearings waiting in the wings ready for the best option!!
What is so frustrating is that for all intents and purposes, everything going back in, as I've measured everything, is exactly as it came out and the stub axle/brake assembly wasn't touched. Can't be that difficult, can it!!
Thanks again

I've always had a dodgy memory for little details. I've recently started taking my mobile phone into the garage and videoing each step, often with detailed views of what im dismantling, before and sometimes, as I take it apart, with commentary on anything i know will be tricky. Then a shot of the parts laid out in order, like an exploded parts diagram, before they are consigned to a bag or box.

Worked brilliantly on the strip down of a CB750, apart from the very tricky left hand wiring loom and components. There I had a fantastic video of the phone descending to the bike lift, dark screen and then the phone rising from the lift again. Repeat for 45 minutes. I'd got out of synch with the record button and was turning it off when I thought I was turning it on... so, not idiot proof

Simon Stephenson said:

Mike, good to hear from you and thanks.
I hear what you say and I've had similar problems with other bikes before, but not to that extent, and if my memory serves me, when it came apart it literally twisted out with no spring effect on the swing arm.
I'm going to try putting the bearing spacer in the other way around as described by another member here and see what happens. I have another set of new bearings waiting in the wings ready for the best option!!
What is so frustrating is that for all intents and purposes, everything going back in, as I've measured everything, is exactly as it came out and the stub axle/brake assembly wasn't touched. Can't be that difficult, can it!!
Thanks again

Click to expand...

Maybe it wasn't set up correctly, especially because you mentioned how chewed up it was and low miles , if only they made it bolt up easy like a Honda and nip up through the inner bearings ! .