Layshaft BALL Bearing Upgrade - "in situ" - Techniques And Tips Help?
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Fast Eddie
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You missed the bit about grinding away at the cradle bit by bit until it fits !
Onder
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No, purposely left it out. Don't want to discourage the timid! With the better diagrams now posted on this list, it is easily done with a hand drill and burr or stone.
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Most likely the case isn't hot enough to release its grip on the bearing. When hot enough the shaft and bearing should just slide out without any violence being required.
If it wont come out then with the primary cover removed heat can be applied here so still no need to remove the gearbox.
Tornado
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I used a propane torch for my bearing removal in situ. Took a good 10-15 min of constant moving flame all around both inner and outer gb shell, with primary all removed as LAB shows. Followed Hemming dvd guidance to heat until water/spittle boils immediately on surface. The bearing came out easily.
Having primary off permitted all bushings to be changed out.
Having primary off permitted all bushings to be changed out.
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I hope the sleeve gear oil seal is going to be replaced after incinerating the gearbox shell. 
Remove the gearbox, check the clusters and shift forks, replace the sundry items, seal, felt, C clip etc.
Based on the average age here being 60's to 70's it would then be refit and forget and will see you out.
If someone removed the complete primary, another half hour would have the box on the bench for the above.
Any force applied to the layshaft ideally needs to be axial.
As far as cradles the cutout is different between 750 and 850 (1972 I do not know) and might be why the 850 can crack on the right lower section.
#
An Edit already liking pictures.
Why do a lot of folk fall down when it comes to home mechanics especially on old (and unknown condition) motorcycles, lazy ? , do not have the tools to make a job not only easy but enjoyable?, do not have the space?, a combination< or something else, who knows.
What I do know is cut a corner now, pay the piper later.
If you have the means to do it 'properly (the peace of mind type) do it properly.
Unless you are doing the 24 hour Lemans in the morning there is no reason torch half the bike in an effort to get one bearing out.
Remove the gearbox, check the clusters and shift forks, replace the sundry items, seal, felt, C clip etc.
Based on the average age here being 60's to 70's it would then be refit and forget and will see you out.
If someone removed the complete primary, another half hour would have the box on the bench for the above.
Any force applied to the layshaft ideally needs to be axial.
As far as cradles the cutout is different between 750 and 850 (1972 I do not know) and might be why the 850 can crack on the right lower section.
#
An Edit already liking pictures.
Why do a lot of folk fall down when it comes to home mechanics especially on old (and unknown condition) motorcycles, lazy ? , do not have the tools to make a job not only easy but enjoyable?, do not have the space?, a combination< or something else, who knows.
What I do know is cut a corner now, pay the piper later.
If you have the means to do it 'properly (the peace of mind type) do it properly.
Unless you are doing the 24 hour Lemans in the morning there is no reason torch half the bike in an effort to get one bearing out.
Last edited:
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Where did you get those tools? I can make the holding tool but not the other. I/2" plate? The holding tool would have to be specific to each sprocket...19t, 20t, 21t..I hope the sleeve gear oil seal is going to be replaced after incinerating the gearbox shell.
Remove the gearbox, check the clusters and shift forks, replace the sundry items, seal, felt, C clip etc.
Based on the average age here being 60's to 70's it would then be refit and forget and will see you out.
If someone removed the complete primary, another half hour would have the box on the bench for the above.
Any force applied to the layshaft ideally needs to be axial.
As far as cradles the cutout is different between 750 and 850 (1972 I do not know) and might be why the 850 can crack on the right lower section.
#
An Edit already liking pictures.
Why do a lot of folk fall down when it comes to home mechanics especially on old (and unknown condition) motorcycles, lazy ? , do not have the tools to make a job not only easy but enjoyable?, do not have the space?, a combination< or something else, who knows.
What I do know is cut a corner now, pay the piper later.
If you have the means to do it 'properly (the peace of mind type) do it properly.
Unless you are doing the 24 hour Lemans in the morning there is no reason torch half the bike in an effort to get one bearing out.
View attachment 111497
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Done with no damage to the sleeve gear oil seal.
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I made them (remembering I am a Boilermaker by trade)
The sprocket holding tool is only for 21T because I have no intention of using other tooth counts, but it would not take much to modify it to take other sizes.
It is 12 mm 6061 and with a split collar (with single M6 clamping cap screw) that attaches to it, it then holds the rotor so the crank nut can also be torqued to spec.
I never had any trouble with layshaft bearings (3 boxes done at once) but if I had I would have machined a small split clamp to fit the layshaft end which would attach to the rocker pin slide hammer. (On the bench of course) so any force was axial.
But in saying that if I had had to do it in situation then definitely with a slide hammer and none of that Yogi Bear fire stuff.
Last edited:
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Winter project Eh?
Just a little more work to pull the trans...
Yes, then...
1. Might as well vapor blast case.
2. Polish or at least clean up covers.
3. Source all new fasteners.
4. Decide to replace/upgrade the Iso's.
5. Since we are this far... Rework/rebuild the swing arm assembly
6. Pin the swing arm shaft, inspect why the center stand is floppy.
To discover the holes are elongated. Either get it bushed, or source different one.
7. Refinish cradle to look new.
8. Reassemble, get pissed when the cradle gets scratched..
9. All new fasteners, New oil lines, New bushings/fasteners for both stands etc..
10. Go ride and enjoy... Till...
Welcome aboard........
Just a little more work to pull the trans...
Yes, then...
1. Might as well vapor blast case.
2. Polish or at least clean up covers.
3. Source all new fasteners.
4. Decide to replace/upgrade the Iso's.
5. Since we are this far... Rework/rebuild the swing arm assembly
6. Pin the swing arm shaft, inspect why the center stand is floppy.
To discover the holes are elongated. Either get it bushed, or source different one.
7. Refinish cradle to look new.
8. Reassemble, get pissed when the cradle gets scratched..
9. All new fasteners, New oil lines, New bushings/fasteners for both stands etc..
10. Go ride and enjoy... Till...
Welcome aboard........
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A blind hole bearing puller kit is fairly cheap on Ebay and does a good job on pulling the layshaft bearing from the case. Again, lots of heat befor pulling the bearing. If you have no intention of making these tools for sale then you might offer the ideas to AN. I did that with the
AN tool # 13.1934 and they produced it.
"Violence" of today produced much frustration but no results. Even if I pull the box, at this point I have my doubts that shaft/bearing is ever going to budge. I got the box hot enough for little red glow dots to appear here and there, and a reading of over 320F (or more) at four or five points, as taken with my heat meter. I've been told IF the P.O. has used Loctite or JB Weld I'm in for a battle Royale. I've even heard of having to cut the back of the box out, do the necessary, and weld it back up. (NOT my wheelhouse!)
Time Warp's notion seems like a decent last resort - "I never had any trouble with layshaft bearings (3 boxes done at once) but if I had I would have machined a small split clamp to fit the layshaft end which would attach to the rocker pin slide hammer." BUT- I'm not visualizing exactly what that looks like. For the record - if someone actually built a puller that worked on the shaft - I'd be a customer!
Having worked on a couple of boxes of "other" brands, all I can say is needing to go through this kind of rigamarole seems at best arcane.
I'm beginning to think it would be easier to swap the whole damn thing for one that's squared away and/or what the HELL I'm missing that is giving me so much grief on a supposedly simple job.
Time Warp's notion seems like a decent last resort - "I never had any trouble with layshaft bearings (3 boxes done at once) but if I had I would have machined a small split clamp to fit the layshaft end which would attach to the rocker pin slide hammer." BUT- I'm not visualizing exactly what that looks like. For the record - if someone actually built a puller that worked on the shaft - I'd be a customer!
Having worked on a couple of boxes of "other" brands, all I can say is needing to go through this kind of rigamarole seems at best arcane.
I'm beginning to think it would be easier to swap the whole damn thing for one that's squared away and/or what the HELL I'm missing that is giving me so much grief on a supposedly simple job.
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Not hot enough , you need to see smoke start .
It's possible if you see red dots forming the P.O. was in there and used red Loctite . Maybe he changed out the bearing already .
If you insist on in situ repairs or replacement I was thinking this : Lean the bike over on the primary side and support it VERY well . Reach under with a heat gun or propane torch on max. to toast up the section of the lower box the bearing finds home in .
Or on the center stand , get under and toast up this area real hot . Safety first , strap it down tight . No accidents allowed .
Under no circumstances cut the box or reweld it up after , who was the fool ? Advice , take it or leave it , for what it's worth .
marshg246
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The problem is that you cannot get to the case on the inside - you're probably heating the layshaft and therefore the bearing more that the case. The heat is normally applied around the bearing which means from the outside as LAB showed. I'm positive JB Weld was not used. Bearing set Locktite, if anything is the correct things to use. I have dropped main bearings from engine case that were installed with red locktite and there's nothing to grab - their weight will do it and that's much harder than what you're dealing with.
If it's too much for you, pack it up and send it to me or to someone else who does this. BTW, where are you located (roughly). You may be near someone who can help.
Guys, you have no idea how much I appreciate your help and encouragement! The bike is already strapped down on the lift and I thought I might tip the whole thing over I was yanking so hard!
I will try heating the case from outside as mentioned. The idea that from the inside I was heating the bearing/shaft as much or more than the case sounds about right, so no more of that.
If that doesn't work --- I live in Roseburg Oregon --- and will likely be willing to send the box out for help --- or possibly put it back together and let the next owner deal with it. (This problem was not in the "Portuguese" brochure! So Greg, if you have to bail me out, can I afford it?)
Commandos are great motorcycles, but my other 9 bikes are beginning to get jealous of how much time, money, and effort I spend on it... at their expense. I also admit to being more interested in riding than wrenching in my old age.
I will try heating the case from outside as mentioned. The idea that from the inside I was heating the bearing/shaft as much or more than the case sounds about right, so no more of that.
If that doesn't work --- I live in Roseburg Oregon --- and will likely be willing to send the box out for help --- or possibly put it back together and let the next owner deal with it. (This problem was not in the "Portuguese" brochure! So Greg, if you have to bail me out, can I afford it?)
Commandos are great motorcycles, but my other 9 bikes are beginning to get jealous of how much time, money, and effort I spend on it... at their expense. I also admit to being more interested in riding than wrenching in my old age.
998cc
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When I removed the and replaced the bearing from the 73 Commando, the gearbox was in situ. I used a propane torch and heated it very well. Using the modified tool below and a slide hammer, the suspect bearing popped right out without major effort. I replaced with a roller bearing but soon after thought a ball bearing would have been best. End float and shimming of the layshaft needed experimentation to result in smooth shifting
This tool came from the local auto parts store. It was so hard, it could not be drilled with cobalt bits. The acetylene torch made a usable hole for the slide hammer.
The jaws needed rounding and slight sharpening to fit the internal diameter and to wedge under the old bearing.
No violence--just determination and working the problem.
Cheers.
This tool came from the local auto parts store. It was so hard, it could not be drilled with cobalt bits. The acetylene torch made a usable hole for the slide hammer.
The jaws needed rounding and slight sharpening to fit the internal diameter and to wedge under the old bearing.
No violence--just determination and working the problem.
Cheers.
marshg246
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Sure you can afford it - read the PMs I sent you. Also, there's a pretty famous club in Oregon - ONE: https://oregonnorton.org/ They have quite a few Norton owners who know Nortons well - some are members here.
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