First time going deep – Gear Box.

NPeteN said:

I just tore everything out of my gearbox, replaced the old stuff and threw it back together. Hope I don't blow up on the highway.

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While I do cursory checks, that's pretty much what I've done on almost 20 Norton transmissions with 100% success.

NPeteN said:

Geez... This is VERY thorough.
I just tore everything out of my gearbox, replaced the old stuff and threw it back together. Hope I don't blow up on the highway.

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As long as your fuel line's the right colour, you'll be okay...

NPeteN said:

Geez... This is VERY thorough.
I just tore everything out of my gearbox, replaced the old stuff and threw it back together. Hope I don't blow up on the highway.

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Maybe I am being overly thorough, and it is taking me a lot longer to finish the gearbox than I thought it would. There is quite a spectrum of folks on this forum. From rocket scientists who race to guys who never worked on bikes before. The advice and recommendations come from across that spectrum. I didn't have any thought of checking shaft deflection till someone asked about it here. I'm not being paid by the hour and I have my other bike to ride, so I figured what the heck. Now I know how to measure shaft deflection.
I probably shouldn't mention that I also magnafluxed the shafts looking for other defects.

NickZ said:

Maybe I am being overly thorough, and it is taking me a lot longer to finish the gearbox than I thought it would. There is quite a spectrum of folks on this forum. From rocket scientists who race to guys who never worked on bikes before. The advice and recommendations come from across that spectrum. I didn't have any thought of checking shaft deflection till someone asked about it here. I'm not being paid by the hour and I have my other bike to ride, so I figured what the heck. Now I know how to measure shaft deflection.
I probably shouldn't mention that I also magnafluxed the shafts looking for other defects.

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Well said! And if you've got the tools to be thorough you are well served to be!

Never hurts to magnaflux!

Ok, going for the Dumb Ass award here.
Had to take most of it out of the gearbox shell again because I had to remove the main shaft so I could get a socket on the gearbox sprocket nut. Of course the Workshop Manual told me to do that right after installing the sleeve gear in section D9, but I thought I would wait on that till I had the rear hub back on, never thinking that there was a reason the manual put that step there.
2nd Dumb Ass achievement was self inflicted. I thought I would be efficient and leave the stator connected to the inner chain case by the seal for the alternator wires. It looked like it was sealed nicely and I chose not to undo it. What I didn't realize was how brittle the insulation had become on that wire and it broke so there was no support where the wires go into the potting material on the stator. With all the moving around with cleaning the case etc, the wires were twisted up and broken. I don't know if that can be repaired. Luckily I have a spare alternator laying around so this wont hold me up. I may try to repair the wiring on the old stator at some later time. I'll attach a photo and maybe someone will tell me that would be a waste of time.

Also of note, some DA other than me had installed the stator opposite way. It was installed such that the wires came out of the stator toward the engine. Bike ran ok though. Maybe no adverse consequences for that.

I need help with this one:

I have everything back in the gearbox shell. Installed the inner cover, torqued 7 nuts to 10 ft-lb. Measure 0.005" end play on lay shaft. I take it through the gears and it goes up and down fine. When in neutral the mainshaft and drive sprocket both turn independently and easily. All seems good so far.
I tighten the gearbox mainshaft nut to 40 ft-lb , and now everything is pretty much locked up. The mainshaft and sleeve gear won't turn independently and can't change gears. I notice that the space between the clutch locating circlip and end of the sleeve gear has been reduced from around 0.155" to 0.100".

I have done 3 iterations of taking inner cover off and inspecting etc. Same result each time. As soon as I loosen the mainshaft nut, all good again.

The things that have changed since it was working:
New sleeve gear bearing, bushes & oil seal,
new lay shaft roller bearing,
new 2nd main bush,
New first gear set, main & lay shaft,
new kickstart shaft bushes,
added 0.035" of shim on kickstart shaft to reduce end play,
new pawl plate on back of inner cover,
new inner cover mainshaft bearing,
new inner cover gasket.

It seems that torqueing the mainshaft nut is causing something to bind, but how do I identify what it is? I measured the new 1st main to be 0.002" longer that the one I took out. Would that be enough to cause this problem?

I will greatly appreciate any help or advice.

By asking that last question I realized that I can answer it myself. So I substituted the old 1st main gear back in and the problem goes away.
My solution would be to take 0.002" off the shoulder of the new 1st main gear.
Am I missing anything here? Would there be any other consequences in doing that? It seems to be like a puzzle where you change 1 thing and another thing pops up elsewhere.

Do you have a gasket between the case & the inner cover?

If yes, use a thicker gasket.

If no, install one.

grandpaul said:

Do you have a gasket between the case & the inner cover?

If yes, use a thicker gasket.

If no, install one.

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I do have a gasket on it. Do you think it would work if I put a second gasket on? Meaning, not leak?

NickZ said:

I do have a gasket on it. Do you think it would work if I put a second gasket on? Meaning, not leak?

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It's worth a try, if the problem is only .002"

grandpaul said:

It's worth a try, if the problem is only .002"

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The existing gasket is 0.020" thick, compressing to about 0.018". As you say, if I only need 0.002", double gaskets would get me to 0.036". Maybe a bit too much. I have ordered some 1/32" gasket material that should get me closer, a little under 0.030" with compression. Either way it will require more shimming for lay shaft play.

Nick
I have always found this shimming stuff to be silly regardless of WHO recommends it.
If your bike jumps out of gear your bushes are NG or the dogs are worn out.
I have never and will never add 35 thou to the layshaft and my gearboxes don't jump out of gear (1st)
see this thread as a prime example:
https://www.accessnorton.com/Norton...ssues-too-long-dogs-update.30395/#post-475470
here the defective/long bush added to the shimming fiasco
Your stator can be fixed...I have done several and it not hard to do
give me a call

dynodave said:

Nick
I have always found this shimming stuff to be silly regardless of WHO recommends it.
If your bike jumps out of gear your bushes are NG or the dogs are worn out.
I have never and will never add 35 thou to the layshaft and my gearboxes don't jump out of gear (1st)
see this thread as a prime example:
https://www.accessnorton.com/Norton...ssues-too-long-dogs-update.30395/#post-475470
here the defective/long bush added to the shimming fiasco
Your stator can be fixed...I have done several and it not hard to do
give me a call

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Questions
Does the sleeve gear moove at all with main bolt tightened.
Does the mainshaft moove at all with the bolt tightened.

I am probably stating the obvious but the gearbox components looked pretty good besides the obvious damage which has been corrected,ie the shafts have good support at both ends and the kicker will be back on line.


If the box was OK before it was dismantled it shouldn't do an about face when its put back together.


If the problem doesn't present itself after considered analysis and NickZ is really stuck, the step by step approach as a last resort perhaps may see him clear.



For example firstly insert the sleeve gear and mainshaft and the supporting cover at the other end of coarse and then tighten the bolt. If Ok then add the coponents in a logical order untill the snag presents itself.

................................

Ive had the same stator problem as outlined above and after attempting to splice the two wire back together ended up just buying a new one.Not what I called an easy job as there wasn't anything to play with. Didn't know what to do about it.

.........................
Hope I have the posting format right this time.

Nick
your thread !
who will answer E questions?

NickZ said:

The existing gasket is 0.020" thick, compressing to about 0.018". As you say, if I only need 0.002", double gaskets would get me to 0.036". Maybe a bit too much. I have ordered some 1/32" gasket material that should get me closer, a little under 0.030" with compression. Either way it will require more shimming for lay shaft play.

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I havent spotted the problem yet though I question whether when adding the 35 thou of shims you may have pushed the free running kick starter gear over enough so as to interfere with the splined section of the layshaft.

dynodave said:

Nick
your thread !
who will answer E questions?

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Sorry mate. Still learning to navigate the sight.
Rgds

Edburt, thanks for your suggestions.
I believe I have gotten to the bottom of this mystery that has had me stumped for a week. I disassembled another gearbox that I have and did some comparisons and tried swapping parts back and forth till I got the problem isolated. Long story short, when I tighten the mainshaft nut, the 2nd main gear was being trapped between 1st main and where the splines step up on the main shaft. The reason for this is a combination of the aforementioned extra 0.002" of the new 1st main gear and what seems to be a main shaft that was machined with less space in the section between the bearing and the spline step up, which is where 1st & 2nd main gears reside. The spare gearbox mainshaft has 1.860", and shaft of the gearbox I'm working on has about 1.852" for that section. Those 2 differences were enough to cause the trapping.
I am in the process of lapping 0.002" off the new 1st main.

Gasket thickness has no effect on this because changing gasket thickness just moves the main shaft relative to the gearbox case, but the problem is in the main shaft stack, which stays the same.

Update:
I finished lapping 0.002" off the new 1st main gear.

Put everything back in the gearbox and voila! Everything doing what it is supposed to.
I then reassembled the primary side, including 4 new friction plates, put everything back on the bike and took a test ride.
Everything seems to function fine. Gears shift smoothly. Neutral seemed a little less easy to find but still always there. Clutch felt good, 2 fingers does it.. I perceive a slightly different grab position but I guess that is to be expected with the stack now about 0.010" thicker.
The only issue is a leak from the primary case 'O'' ring. But I know how to deal with that.

She's back!!!!


Thanks everyone for all the helpful suggestions and encouragement.