Digging deeper into the gearbox

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seattle##gs

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I dismantled the GB to see if I had done something wrong during the rebuild. Reluctant to go into first without chattering...and shifting requires more foot pressure than normal. All new bushings...all new bearings...everything turns freely. The only thing I did not rebush was the camplate and quadrant. I am about to do that but have little faith that will be the cure.
Has anyone noticed a difference once the bushings in the C&Q were replaced? I can see the camplate cocking in it's bush as I shift. The quadranr appears to be held straight.
 
seattle##gs said:
I dismantled the GB to see if I had done something wrong during the rebuild. Reluctant to go into first without chattering...and shifting requires more foot pressure than normal. All new bushings...all new bearings...everything turns freely. The only thing I did not rebush was the camplate and quadrant. I am about to do that but have little faith that will be the cure.
Has anyone noticed a difference once the bushings in the C&Q were replaced? I can see the camplate cocking in it's bush as I shift. The quadranr appears to be held straight.
Click to expand...
What about the unusual drag on the the sleeve gear bushes you mentioned in the other thread?

Did you put an indicator on & check runout (30 second job) like I mentioned?
 
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seattle##gs said:
I dismantled the GB to see if I had done something wrong during the rebuild. Reluctant to go into first without chattering...and shifting requires more foot pressure than normal. All new bushings...all new bearings...everything turns freely. The only thing I did not rebush was the camplate and quadrant. I am about to do that but have little faith that will be the cure.
Has anyone noticed a difference once the bushings in the C&Q were replaced? I can see the camplate cocking in it's bush as I shift. The quadranr appears to be held straight.
Click to expand...
I generally associate the term chatter with a clutch.

Make sure the cam plunger moves freely and the surface on the dome of the plunger is smooth. That plunger housing can get a lot of fine grit in it. Usually results in not holding the quadrant solidly and missed shifts rather than hard shifting.

Only time I had hard shifting with an old Norton gearbox was when the bearing in the clutch was failing and not spinning freely and the friction plates were sticking from excess heat and lack of oil. It was an aftermarket NEB wet clutch though. Made similar to a Commando clutch, but with multiple small springs rather than the large diaphragm spring.

I did rebuild my gearbox for grins, but honestly can't remember if I replaced the C&Q bushings. If those bushes did come in the Andover gearbox rebuild kit, I did. Otherwise, I did not replace them.

I'm not sure if I can be less helpful. I think I probably accomplished a useless post though.
 
I put the mainshaft in my Chinese lathe and ran the dial indicator along the length of the sleeve gear area. .0015 was the runout.
Potential problem with the readings..I only have a 3-jaw chuck so no way to center it. As I roll the chuck around I can easily see that it is not centered. I need to get a dead center to replace the chuck for this operation.

The clutch is the standard Commando diaphragm. The chain looks good but I might give it a tiny bit more slack just for something to do.

I was thinking that possibly the C&Q were cocking in their bushings and creating a drag somehow...possibly...maybe...I'm grabbing at straws.
 
seattle##gs said:
I put the mainshaft in my Chinese lathe and ran the dial indicator along the length of the sleeve gear area. .0015 was the runout.
Potential problem with the readings..I only have a 3-jaw chuck so no way to center it. As I roll the chuck around I can easily see that it is not centered. I need to get a dead center to replace the chuck for this operation.

The clutch is the standard Commando diaphragm. The chain looks good but I might give it a tiny bit more slack just for something to do.

I was thinking that possibly the C&Q were cocking in their bushings and creating a drag somehow...possibly...maybe...I'm grabbing at straws.
Click to expand...
Check the runout of the sleeve gear, as installed in the bearing, in the case, with the sprocket & nut on.
71B8E88B-0BBF-47D9-BC8A-E3D7DDAC9FA6.jpeg
 
My gb did not have shifting issues follow complete rebuild. Did it all in frame. The C&Q bushes were tricky to do with gb in frame, but managed to rig a bit of all thread and suitable diameter socket to make up a puller. I never found an actual figure for how much of a gap to leave outer end of bush to case surface for the o-ring to sit in. The Hemmings video just says leave a gap. The Norman White book says to be sure to make a measurement on original gap prior to replacing (did the overhaul before I had the book). So just did as I saw fit. And I have pretty persistent seeping of fluid from both those bush openings. The o-rings don't appear to be in good compression contact with the bolt washers.
 
seattle##gs said:
I put the mainshaft in my Chinese lathe and ran the dial indicator along the length of the sleeve gear area. .0015 was the runout.
Potential problem with the readings..I only have a 3-jaw chuck so no way to center it. As I roll the chuck around I can easily see that it is not centered. I need to get a dead center to replace the chuck for this operation.

The clutch is the standard Commando diaphragm. The chain looks good but I might give it a tiny bit more slack just for something to do.

I was thinking that possibly the C&Q were cocking in their bushings and creating a drag somehow...possibly...maybe...I'm grabbing at straws.
Click to expand...
Put a small piece of round in your chuck and taper turn it to a point
It won't matter how far out your chuck is because the point will be centered
👍
 
seattle##gs said:
I need to get a dead center to replace the chuck for this operation.
Click to expand...
Why don't you make a dead center? If you just use a 3/4" rod of any kind of steel, you can cut a fresh taper with your compound every time you use it and have a dead nuts center every time.

Back to the gearbox...
 
Grandad said:
Try a larger / thicker o ring or shim the o ring maybe ???
Click to expand...
I did try putting a second o-ring under each washer by just stretching them over the in place washers. Seemed to help for a while but seep is back. Heard not to remove the pivot bolts without removing both inner and outer gb covers as the C or Q or both will fall out of place. So further fixes need to have the covers off. Might have a go over winter.
 
seattle##gs said:
I dismantled the GB to see if I had done something wrong during the rebuild. Reluctant to go into first without chattering...and shifting requires more foot pressure than normal. All new bushings...all new bearings...everything turns freely. The only thing I did not rebush was the camplate and quadrant. I am about to do that but have little faith that will be the cure.
Has anyone noticed a difference once the bushings in the C&Q were replaced? I can see the camplate cocking in it's bush as I shift. The quadranr appears to be held straight.
Click to expand...
You may have done this already - but using the OldBritts manuals, especially the one on Assembling the Commando Gearbox. (BTW @Jerry Doe this one appears to be missing from the resources).
I suspect your shifting difficulties may be a poorly adjusted hairspring - covered in pages 14 & 15 in the above doc.

If you want a copy, PM your email address to me and I'll send you a copy.

There are three others (which are in the Resource library of this forum):
Dismantling and Inspecting the Commando Gearbox
Gearbox Assembling Checklists
Eliminating Leaks due to pressure build-up in the Commando Gearbox

Cheers
 
robs ss said:
Eliminating Leaks due to pressure build-up in the Commando Gearbox
Click to expand...

That one, however, can be ignored as there's no way for pressure to build up inside the gearbox.
www.accessnorton.com

850 inner/outer gearbox leak question

Hello all I am in the process of installing new gaskets for the gearbox so far I have removed outer cover now need to remove inner..... I have a manual have read it but I am looking for inside tips or tricks... When I remove it what should I look out for... Is there re install tricks.. Also...
www.accessnorton.com www.accessnorton.com
 
robs ss said:
You may have done this already - but using the OldBritts manuals, especially the one on Assembling the Commando Gearbox. (BTW @Jerry Doe this one appears to be missing from the resources).
I suspect your shifting difficulties may be a poorly adjusted hairspring - covered in pages 14 & 15 in the above doc.

If you want a copy, PM your email address to me and I'll send you a copy.

There are three others (which are in the Resource library of this forum):
Dismantling and Inspecting the Commando Gearbox
Gearbox Assembling Checklists
Eliminating Leaks due to pressure build-up in the Commando Gearbox

Cheers
Click to expand...
www.accessnorton.com

Old Britts - Assembling the Commando gearbox

Old Britts - Assembling the Commando gearbox
www.accessnorton.com www.accessnorton.com
 
Good idea on the dead center. I should have thought of that myself. I am a self taught machinist so some of this stuff escapes me.
 
So I made the dead center. When running the dial indicator lengthwise there's only .001 variation. When rolling the shaft there's about .007
difference which suggests the center bore is not concentric with the O.D. Any explanation?
 
seattle##gs said:
So I made the dead center. When running the dial indicator lengthwise there's only .001 variation. When rolling the shaft there's about .007
difference which suggests the center bore is not concentric with the O.D. Any explanation?
Click to expand...
Centerless grinding.
Is that a NEW shaft? Or veteran?
 
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