Rear wheel spacer on 74 Commando too tight

Status
Not open for further replies.
D

Drummer99

VIP MEMBER
Joined
Oct 18, 2013
Messages
157
Country flag
I am having difficulty fitting the long spacer into position between the swing arm and the speedo drive on my 74 commando. It seems that it wont fit into place unless i spread the swing arm. Also the Parts manual shows a very thin washer between the spacer and the speedo but i doubt this would fit. Would appreciate any thoughts on putting this together I assumed it would be a tight fit but not this tight?
Thx
Jack
 
I took my rear wheel apart a couple months ago to fit new brakes, cush rubbers, clean and re-grease the speedo. I found that re-assembling with the same parts I had to spread the swing arm slightly to get it to fit.
 
Mine only has the spacer with no washer, it is a tight fit but it will go in, sometimes a bit hard when you are putting the wheel back on by yourself but mine you my frame is a Featherbed frame running a Commando wheels but it was the same with the Commando swingarm and if you put new shock rubbers in the hub the first time will be harder to get that spacer in position.

Ashley
 
Drummer99 said:
I am having difficulty fitting the long spacer into position between the swing arm and the speedo drive on my 74 commando. It seems that it wont fit into place unless i spread the swing arm. Also the Parts manual shows a very thin washer between the spacer and the speedo but i doubt this would fit. Would appreciate any thoughts on putting this together I assumed it would be a tight fit but not this tight?
Thx
Jack
Click to expand...

Hi Jack
the item that you refer to (thin washer) is actually a top hat shaped item #34 which goes through the speedometer gearbox. check for NM.13270. speedo-gear-rubbing-hub-t5631.html
Make sure the cush drive buffers are not snagging up the wheel hub from going in all the way.
Cheers,
Thomas
CNN
 
I had a similar problem with my Atlas .... traced it to a bow in the swing arm. The drive side arm was bowed inward. Had to use a 30 ton press to straighten.

If you can spread the swingarm with the fingers to get the spacer in, that is acceptable. If not, something is out of spec.

You might review my thread on this problem ...
atlas-rear-wheel-fitting-and-dimensions-t20898.html
There were lots of suggestions by others that may apply to you.

Madass and DynoDave gave dimensions in the thread for the normal Featherbed swingarm spread, but caution! ... I think Cdo spread is slightly wider. You should research the normal Cdo swingarm spread dimension and check against yours.

Slick

FWIW .... if it turns out to be a bow in one of the swing arm legs, refer to this thread for tips on straightening.

truing-swing-arm-t20914.html
 
I had the same problem after rebuilding my 71. I needed to use a pry bar and block to get enough force to get the spacer in. after about a year of this and being sure nothing was wrong with the assembly, I cut the long spacer to length. Much easier now.
 
New cush drive rubbers can cause this as the hub paddles don't go in fully enough at first. The main axle will draw things in proper , but you have to fit that long spacer first up against the speedo drive gearbox. It's easier next removal and re-fitting the wheel because the nylon cush pucks have compressed a bit more by then.
 
folks thanks for all your help I have also rebuilt the entire system new cush rubbers etc. also the spacer is stainless steel and I have determined it is slightly longer than the original maybe .010 I will spread the swing arm slightly to get it in and then pull it all up with the axle bolt. I will let you know how it goes
thx
Jack
 
I believe it is normal for it to be a tight fit. You just have to hold your tongue right. :)
 
Yes it is especially difficult when new cush rubbers have been fitted, however I still have this problem many years after fitting them.
 
It is not normal to have to lever the swing arms apart to fit the last spacer. Norton certainly did not intend such to be the case ... especially with the bolt up wheel.

If you have an interference fit of the order 0.1 inch or more, something is wrong!!! I know 2 Cdo guys who had 1/8 inch interference and just lever spread the arms and went on .... the bikes apparently can swallow that, but wheel centering might be affected.

However, the proper thing to do is measure the spread on the arms and check with specifications, then go from there. Perhaps someone will chime in and inform us what the Commando inside distance should measure. The inside distance of the swing arms for a Featherbed frame is 7.895 inch*, and when one adds up all the distances involved, i.e., the hub, spacers, speedo GB, etc, it comes to exactly that ... no interference!

Slick

* Average of measurements courtesy of Madass and DynoDave. Manufacturing tolerances can be +/- 0.060". One can likely finger spread this much.

LAB: Thanks for the link (below)

Re: Swinging Arm Dimensions

Postby madass140 » Sat Sep 07, 2013 1:58 am
Slimline is 7-7/8"
Commando is 8-1/16"
 
texasSlick said:
Perhaps someone will chime in and inform us what the Commando inside distance should measure. The inside distance of the swing arms for a Featherbed frame is 7.895 inch*, and when one adds up all the distances involved, i.e., the hub, spacers, speedo GB, etc, it comes to exactly that ... no interference!
Click to expand...

swinging-arm-dimensions-t17329.html#p215161
 
On my 1974 Commando I measured the width of the swingarm and found it to be 8 1/16 inches wide. I then measured the width of all of the components that would fit in between the swingarm. I found the measurement to be 8.148 inches which includes one .032 inch shim that goes in the brake drum area and also a brand new speedometer drive. This dimension is .085 of an inch wider than the width of the swingarm. I had shortened the right hand spacer to .080 of an inch. After shortening the spacer I checked the sprocket alignment and found it to be fine. I figure that possibly the rear wheel is now offset to the right .040 of an inch. Now my rear wheel is relatively easy to install.

Another thing I found on my Commando is that when the rear wheel was installed the brake drum was rubbing into the rear wheel hub. This may contribute to additional difficulty when installing the wheel. I ended up machining my brake drum so that I would have proper clearance between the drum and the hub.


Rear wheel spacer on 74 Commando too tight

The arrow points to where I machined away some material from the brake drum to get the necessary clearance between the drum and the hub


Peter Joe
 
Ok I have installed the spacer and tightened the axle bolts up The brake shoes seem to be dragging on the brake drum and the wheel does not turn freely if I loosen the bolts slightly it will turn more easily It seems like it is binding and dragging on the brake drum. Is there away to adjust the brake shoes ? Or as the thread earlier said perhaps the drum is rubbing on the hub. I am going to measure the swing arm distance and see what I have now that the wheel is installed. Any thoughts would be appreciated
Thx
Jack
 
Drummer99 said:
Ok I have installed the spacer and tightened the axle bolts up The brake shoes seem to be dragging on the brake drum and the wheel does not turn freely if I loosen the bolts slightly it will turn more easily It seems like it is binding and dragging on the brake drum. Is there away to adjust the brake shoes ? Or as the thread earlier said perhaps the drum is rubbing on the hub. I am going to measure the swing arm distance and see what I have now that the wheel is installed. Any thoughts would be appreciated
Thx
Jack
Click to expand...

My after market shoes rubbed and had to be linnsihed a tad to clear. I would sugges that is your issue.

The inner portion of the drum that the previous poster had to machine only rubs as the cush drive 'gives' not as the wheel rotates.
 
There is washer, part #21 on the exploded parts view, to be used 'as required' to space the brake plate/shoes away from the brake drum.
If that is where your contact is happening.
 
Another possible reason that would cause the brake drum to rub is that the snap ring bearing retainer within the brake drum unseated allowing the brake drum to shift over and rub into the brake shoes and backing plate. This could have happened while struggling to install the wheel with new cush drive rubbers. If this is the problem make sure that the snap ring is installed correctly and then use a hammer and a drift to ensure that it is completely seated.

Peter Joe
 
With new or newish cush rubbers installed I found the only way to get the wheel and drum back together was to assemble
it all off the bike and then put it back as one piece, hub and drum and backing plate.
If I had not just had a new Devon rim laced to my polished hub by Buchanan Id readily purchase Madass's new cush hub
offering.
 
Drummer99 said:
Ok I have installed the spacer and tightened the axle bolts up The brake shoes seem to be dragging on the brake drum and the wheel does not turn freely if I loosen the bolts slightly it will turn more easily It seems like it is binding and dragging on the brake drum. Is there away to adjust the brake shoes ? Or as the thread earlier said perhaps the drum is rubbing on the hub. I am going to measure the swing arm distance and see what I have now that the wheel is installed. Any thoughts would be appreciated
Thx
Jack
Click to expand...

Jack
When you are tightening up the axle shaft and the drum side nut to dummy axle, you need to apply the rear brake hard to centralize the brake/sprocket drum to the shoes. This should cure the dragging issue. I have found that new rubber cush pads sometimes need to be trimmed with a little trip on the belt sander to get the whole assembly to fit up properly. These are sometimes very tight. I have also found the pockets that the cush pads live in and the tongs on the drum are shallower than the total length of the tongs. Little adjustments after making some measurements may be needed.
Hope that helps.
Cheers,
Thomas
CNN
 
PeterJoe mentions the importance of the large circlip retainer for the double row bearing being correctly in it's hub groove , and tapped deep into it. There is a rounded edge and a sharper edge to it. The round edge fits towards the bearing and the other side (sharp) goes towards the wheel itself. It will pop out and ruin your day if fitted wrong. It is standard practice to fit a new retainer ring circlip every time , I have helped 2 buddies with this nagging mysterious hub rubbing issue in the past 2 years where upon inspections the circlip was out of it's groove and the bearing was basically drifting about in it's bore. Take a look and use the opportunity to repack with grease this often neglected pricey bearing. Then try fitting again. :)
 
Status
Not open for further replies.

Similar threads

W
  • Locked
Question on 74 Commando wheels.
Replies
16
Views
970
Onder
Onder
D
  • Locked
Timing side 850 Commando new Superblend bearing too tight
Replies
19
Views
1,761
Onder
Onder
Burgs
  • Locked
Rear Wheel Spacers 1972 750 Commando Need Spacer Lengths
Replies
0
Views
778
Burgs
Burgs
motorick
  • Locked
Rear Wheel Bearing Too Tight
Replies
2
Views
1,018
L.A.B.
L.A.B.
D
  • Locked
Front Vernier Isolastic too tight
Replies
12
Views
1,367
toppy
T
Back
Top