very nitpicky gearbox questions.

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seattle##gs

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Tonight I dismantled an 850 gearbox. It was an unknown lump in a box. It shifted easily while locked in the vice. Very surprising, the outer screws were unmolested and the threads were clean, suggesting the GB has never been apart. So I took the opportunity to study an unmolested GB. It appears to have low miles because the mainshaft is in very good condition as are all the other bushings except for the first gear lay. The mainshaft has three bushings instead of the usual two. The bushings in the quadrant and camplate assy had no play in them at all, very unusual. I would put this box back together with new seals and call it good.......except for one big problem. The bearings on the left side fall out of the case even when it's cold. I have 4 more gear cases just like this. Tonight I emailed AN to PLEASE supply these bearings in an oversize form, perhaps .002 and .003 to save these cases. I wouldn't be surprised if at least 60% of riders have this same problem, riding around and don't even know it. Cross your fingers everyone and hope AN can come up with a solution short of buying a new gear case for about $400 with shipping. You might email them yourselves about this.

Here comes the nitpicky part...It all concerns the bushings for the quadrant and camplate. They protrude into the case and act as a thrust bearing. On this very good box the "stick out" measures roughly .166 and holds the quadrant almost touching the camplate. Usually the quadrant is almost touching the gear case. The stick out for the camplate is approx .122. Do you think these dimensions are really critical? Do you know the exact dimensions?
Also' on the other side of the bushing, on the outside of the box, there is a boss that holds the bushing and an o-ring. I notice on all boxes the bushing stands slightly proud of the boss (this is internal) perhaps .020. Is this slight overhang important or can the bushing go flush? I don't see the need for the overhang, please enlighten me.
I told you this was nitpicky.
 
Let's say AN were able to deliver oversize bearings. Do you think it likely that the cases would continue to wear and allow these oversize bearings to move as well?

I have recovered a loose sleeve gear bearing with Loctite bearing fit, it might last just as long as an oversize bearing.

Personally, I suspect that supplying oversize would be difficult to achieve since the bearings are to standard specifications on ID and OD etc. Surely they would be dependent on a manufacturer having already tooled up to do that for stock? And in the case of the layshaft they are already picky on supplier as we know.

Might it be better to develop an insert solution? I imagine amazing things could be done with a CNC made insert and a CNC programme to cut the box for it?

But, might that cost more than the $400 with Transatlantic shipping for a gearbox shell, which, honestly, seems good value.
 
Last edited:
seattle##gs said:
Tonight I dismantled an 850 gearbox. It was an unknown lump in a box. It shifted easily while locked in the vice. Very surprising, the outer screws were unmolested and the threads were clean, suggesting the GB has never been apart. So I took the opportunity to study an unmolested GB. It appears to have low miles because the mainshaft is in very good condition as are all the other bushings except for the first gear lay. The mainshaft has three bushings instead of the usual two. The bushings in the quadrant and camplate assy had no play in them at all, very unusual. I would put this box back together with new seals and call it good.......except for one big problem. The bearings on the left side fall out of the case even when it's cold. I have 4 more gear cases just like this. Tonight I emailed AN to PLEASE supply these bearings in an oversize form, perhaps .002 and .003 to save these cases. I wouldn't be surprised if at least 60% of riders have this same problem, riding around and don't even know it. Cross your fingers everyone and hope AN can come up with a solution short of buying a new gear case for about $400 with shipping. You might email them yourselves about this.

Here comes the nitpicky part...It all concerns the bushings for the quadrant and camplate. They protrude into the case and act as a thrust bearing. On this very good box the "stick out" measures roughly .166 and holds the quadrant almost touching the camplate. Usually the quadrant is almost touching the gear case. The stick out for the camplate is approx .122. Do you think these dimensions are really critical? Do you know the exact dimensions?
Also' on the other side of the bushing, on the outside of the box, there is a boss that holds the bushing and an o-ring. I notice on all boxes the bushing stands slightly proud of the boss (this is internal) perhaps .020. Is this slight overhang important or can the bushing go flush? I don't see the need for the overhang, please enlighten me.
I told you this was nitpicky.
Click to expand...
I wonder if someone in your area has been pressing the bearings in rather than heating the case and dropping them in. The only loose one I've had was due to a bent main shaft. Do the cases have a crack between the bearings? If so, hairline or open?

Bearing retainer used correctly will make those cases usable if that's all that's wrong.
 
This is a collection of cases over the years. I won't throw them away but they are essentially useless. I could go with the very strong bearing retainer stuff but it takes a very high heat to melt it if I ever want to get the bearing out. It is pretty much permanent then.
What I would like is a sleeve about .001 thick that would need to be shrunk on to the bearing and then heat the gearbox up to
250 -275 degrees and drop the bearing with sleeve into it.
 

SKF

www.skf.com www.skf.com

Something like a speedisleeve , but i am affraid they do not have any one thou thick in the 2.5" OD range ??
 
How about using a piece of shim stock cut to size ??

Copper plate the O/D of the bearing ???

Each will work, I've used both methods in the past (not Norton but in Engineering shop at work ).
 
seattle##gs said:
The mainshaft has three bushings instead of the usual two.
Click to expand...

The sleeve gear?
Mk2/2A "850" gearbox? Does this particular sleeve gear have a groove and wire circlip at the outer end? I also have one of those with three bushes/bushings. Although the Mk2/2A parts book lists two bushes the addition of the third bush could have been a factory modification until the two longer "Mk3" bushes were introduced.
seattle##gs said:
Here comes the nitpicky part...It all concerns the bushings for the quadrant and camplate. They protrude into the case and act as a thrust bearing. On this very good box the "stick out" measures roughly .166 and holds the quadrant almost touching the camplate. Usually the quadrant is almost touching the gear case. The stick out for the camplate is approx .122. Do you think these dimensions are really critical? Do you know the exact dimensions?
Also' on the other side of the bushing, on the outside of the box, there is a boss that holds the bushing and an o-ring. I notice on all boxes the bushing stands slightly proud of the boss (this is internal) perhaps .020. Is this slight overhang important or can the bushing go flush? I don't see the need for the overhang, please enlighten me.
Click to expand...

As I see it, the bushes should be fitted to a depth that eliminates all end float so oil doesn't leak past the O-rings or perhaps should slightly compress the O-ring.
 
L.A.B. said:
The sleeve gear?
Mk2/2A "850" gearbox? Does this particular sleeve gear have a groove and wire circlip at the outer end? I also have one of those with three bushes/bushings. Although the Mk2/2A parts book lists two bushes the addition of the third bush could have been a factory modification until the two longer "Mk3" bushes were introduced.
Click to expand...
I've seen quite a few with no circlips and what looks like three bushings (or is it two bushings and a spacer). Until this, I thought that was normal for the no circlip variety :confused: I've never had to replace them and actually thought the middle one was a spacer or a part of the sleeve gear itself (in other words, push one bearing in from each side). Hopefully I still have one and can investigate.
 
marshg246 said:
I've seen quite a few with no circlips and what looks like three bushings (or is it two bushings and a spacer).
Click to expand...

The pre-Mk2/2A (excluding the "1968" 040422) sleeve gear 061057 had two 'short' 040062 bushes, no groove for a circlip and no spacer that I'm aware of.
andover-norton.co.uk

Andover Norton Parts Drawings - Genuine Andover Norton Factory Parts - Commando Parts

Andover Norton Parts are the only Norton spare parts in the market manufactured to original drawings, within the factory-approved tolerances, from the correct materials, and with the correct finish.
andover-norton.co.uk

The Mk2/2A sleeve gear is 064991. This sleeve gear has a single groove at the outer end for the 064989...Sleeve Gear Circlip...1
(at the bottom of the page list with no item number) two short bushes are listed but it would seem they began fitting three at some point.

The Mk3 sleeve gear is 065954 and has a circlip groove both ends, 064989...Circlip...2 and two 'long' 066203 bushes and the only sleeve gear available from AN (although currently "out of stock").
 
L.A.B. said:
The pre-Mk2/2A (excluding the "1968" 040422) sleeve gear 061057 had two 'short' 040062 bushes, no groove for a circlip and no spacer that I'm aware of.
andover-norton.co.uk

Andover Norton Parts Drawings - Genuine Andover Norton Factory Parts - Commando Parts

Andover Norton Parts are the only Norton spare parts in the market manufactured to original drawings, within the factory-approved tolerances, from the correct materials, and with the correct finish.
andover-norton.co.uk

The Mk2/2A sleeve gear is 064991. This sleeve gear had a single groove at the outer end for the 064989...Sleeve Gear Circlip...1
(at the bottom of the page list with no item number) two short bushes are listed but it would seem they began fitting three at some point.

The Mk3 sleeve gear is 065954 and has a circlip groove at both ends, 064989...Circlip...2 and two 'long' 066203 bushes and the only sleeve gear available from AN (although currently "out of stock").
Click to expand...
Agree with all, except I've seen what he asked about - 061057 with three bushes. In fact, I just went through my collection of 061057 and here's what I found:

1) One as expected with two .88" bushes
2) One with three .88" bushes
3) One with one long and one .88" bush.

In all cases the total length of the bushes is less than the length inside the sleeve gear so no problem.

I'm guessing that people just mixed and matched over the years with what they thought would be a good idea.
 
marshg246 said:
Agree with all, except I've seen what he asked about - 061057 with three bushes.
Click to expand...

Where is 061057 mentioned? The only information so far is that it's an "850" gearbox. If it happens to be a Mk2/2A gearbox then it should have the 064991 sleeve gear.,

The NOC Service Notes mention the fitting of a third bush.
 
marinatlas said:


Nice job here , but need some practice (at least !!!)
Click to expand...

Nice job indeed, but I would want to run that gearbox for about 2000 miles, then open it up to see if there was a crack between the two bearing bores before I really trusted it.
 
Last edited:
L.A.B. said:
Where is 061057 mentioned? The only information so far is that it's an "850" gearbox. If it happens to be a Mk2/2A gearbox then it should have the 064991 sleeve gear.,

The NOC Service Notes mention the fitting of a third bush.
Click to expand...
It's mentioned in your post where you tell the three types. Also, going through all the actual parts manuals, it appears that it was used in at least some 850s (MK1/MK1A?)

750 Manual 101/71 061057
750/850 Manual 065034 061057
850 Manual 065988 064991 (no circlip shown or normally listed but one listed with no reference at the bottom of the page)
MK3 Manual 005756 065953 (2 circlips listed)

I, like everyone else had no idea what gearbox parts are in the "850 gearbox" he took apart. I just got off the phone with him - it's the 1 circlip version and does have three bushings. I checked my two one circlip sleeve gears, both have three bushings.
 
marshg246 said:
It's mentioned in your post where you tell the three types. Also, going through all the actual parts manuals, it appears that it was used in at least some 850s (MK1/MK1A?)
Click to expand...

Ok, as what you said was: "what he (seattle##GS) asked about - 061057 with three bushes.", when in fact he hadn't mentioned the sleeve gear at all (but as "the mainshaft has three bushings..."). I have no argument about 061057 being used prior to Mk2/2A as I'd already said: "The pre-Mk2/2A (excluding the "1968" 040422) sleeve gear 061057".

marshg246 said:
I, like everyone else had no idea what gearbox parts are in the "850 gearbox" he took apart. I just got off the phone with him - it's the 1 circlip version and does have three bushings. I checked my two one circlip sleeve gears, both have three bushings.
Click to expand...

Alright, so it is the 064991 sleeve gear then.
 
Last edited:
L.A.B. said:
Ok, as what you said was: "what he (seattle##GS) asked about - 061057 with three bushes.", when in fact he hadn't mentioned the sleeve gear at all (but as "the mainshaft has three bushings..."). I have no argument about 061057 being used prior to Mk2/2A as I'd already said: "The pre-Mk2/2A (excluding the "1968" 040422) sleeve gear 061057".



Alright, so it is the 064991 sleeve gear then.
Click to expand...
I believe you will find that you were the first to type sleeve gear and I was trying to add some info to what you said - I did not respond to him on the bushings here. I certainly did not contradict you in any way. F'it. Not possible to get the point across. I'm out.
 
marshg246 said:
I believe you will find that you were the first to type sleeve gear
Click to expand...

Yes, I did so what was "Agree with all, except I've seen what he asked about - 061057 with three bushes." when "he" didn't?
When I said: "Where is 061057 mentioned?" I was referring to seattle##gs' post not my own, obviously!
marshg246 said:
I certainly did not contradict you in any way. F'it. Not possible to get the point across. I'm out.
Click to expand...

No, but I'd already mentioned 061057 being "prior" to Mk2/2A so required no further explanation.
 
seattle##gs said:
This is a collection of cases over the years. I won't throw them away but they are essentially useless. I could go with the very strong bearing retainer stuff but it takes a very high heat to melt it if I ever want to get the bearing out. It is pretty much permanent then.
What I would like is a sleeve about .001 thick that would need to be shrunk on to the bearing and then heat the gearbox up to
250 -275 degrees and drop the bearing with sleeve into it.
Click to expand...
If you use the regular Loctite retainer, not the high temp stuff, it will work ok. You only need 250 C to break it. That is only about a third of the melting point temperature of aluminium so pretty safe.
 
will investigate the loctite products.
I mentioned the 3 bushing sleeve gear simply as an observation, not as a question. I like the idea of using the three bushings and perhaps cross drilling the center bushing to make a couple of oil reservoirs.
I wonder if AN can talk to Speedisleeve about this problem.
 
Putting three bushes in the older type was/is a fairly common modification. Particularly before the longer ones existed. The two bushes tended to move and the extra bush helped prevent this, plus it gives a bigger bearing area. I put three in mine many years ago and also fitted a hardened washer over the mainshaft against the outside of the sleeve gear to stop the bush moving outward. Maybe your gearbox has been apart in the past and someone fitted the extra bush.
 
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