Final Drive Sprocket -end play on shaft -allsorted out!

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

pkeithkelly,

This is what I used as reference when I rebuilt my gear box.
https://www.oldbritts.com/gearbox_d.html
https://www.oldbritts.com/gearbox_a.html

Things I found out along the way.
To remove the sprocket nut I used a 1 1/2" deep well socket that I cut in half and welded a piece of black pipe in between the two pieces to make it deeper.

Buy or borrow the tool to remove the lever body nut.(Makes life a little easier)
http://www.ebay.com/itm/Gearbox-Lockrin ... 1289591110

Use Hylomar gasket sealer. In case you have to open the box up again it will release easier.

Take your time and it should go well. Good luck.

Pete



Fred has a lot of good tech articles. Take your time and it should go well.

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

A couple of comments here. Most of us refer to bearing 040098 (also 04-0098) as the "Sleeve Gear Bearing" because that's what it's called in the factory parts books from 1971 on. Also called "Bearing, Sleeve Gear" in the MKIII parts book. It's referred to as the "Main gear ball bearing" in the 1968 - 1970 parts books. It's quite possible that it is referred to as the "Left Side Mainshaft Ball Bearing" in some other factory parts book, but I haven't run across that term yet.

As others have mentioned, the most likely cause of the slop is the sleeve gear being loose in the gearbox shell. The movement of the sleeve gear bearing is limited by contact with the layshaft 4th gear, so it's not going to move any further in the future, but it's not going to get any better either. Since you already have the primary off, this would be a great time to tear the gearbox down and inspect it.

Ken

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

Thanks all.

I'm now clear on which bearing was referred to as the "sleeve gear bearing" (04-0098).

I will start opening things up as soon as I get the wrench I ordered to remove the gearbox sprocket nut.

Will follow your advice first, Toppy, i.e., to pull off the oilseal and sprocket spacer, to get a better idea of what is moving and what isn't. Will then strip out the gearbox from the other side and replace what's necessary.

The bike has 27,000 miles and other than this accidentally discovered issue, runs like a top.

toppy said:

Working from the outside of the gearbox (these parts need to come off to strip the box anyway) remove the drive chain sprocket from the sleeve gear.
You should then be able to see the oil seal and spacer that the seal runs on. Using small screwdrivers or other sharp pointed tools even drilling tiny holes an screwing in small self tapping screw then pull on screw you should be able to prize out the seal without to much force. This will wreck it but they are cheap to replace an should be changed anyway as should the spacer if it shows even the slightest sign of a groove made by the seal.
Now you should be able to see the inner race of the bearing ( yes the one you Pete V and Madass are talking about ) and by pulling and pushing the sleeve gear see if...
1. The sleeve gear moves but the bearing stays still.
2. The bearing an sleeve gear move together. (The most common i believe)

Click to expand...

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

Do ya really think this big ole sprocket nut needs 70 lb of torque as its not under much sideways loads being located by tanny shaft and chain runs, so bulldozer scale socket contruction not needed to get on with the show. Wes and I get away fine with a 1.5 inch end wrench to snug down quite hard enough to align the lock tab screw. This also makes holding the shaft stable to torque on more reasonable level devices-methods. Easy to forget its reverse threads - for a while in my case.

Btw is it possible if main shaft TS nut loose to cause this owners shifting? The symptoms I had were on the road with shifting difficulty and getting clutch adjusters to take up enough slack with clutch basket/main shaft group shifting instead.

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

As Hobot says, be aware that the sprocket nut is a left hand thread. You should be able to see whats happening by simply removing the spacer behind the sprocket with a gripping tool of some sort, it is only pressed in by hand. If necessary there will then be sufficient space to pry the seal off with a screwdriver.

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

Update:

Removed the lock nut and the gearbox sprocket a few minutes ago. I managed to pry out both the Mainshaft Oilseal and the Sountershaft Sprocket Spacer. (Have new ones on order)

I can plainly see both the Sleeve Gear and the Sleeve Gear Bearing sliding back and forth along the mainshaft. The Sleeve Gear moves in and out just a bit more than the bearing. What is supposed to be on the gearbox side of these two parts to prevent this movement?

The outside race of the bearing itself seems to be well seated in the gearbox shell, and the bearing seems to look just fine. (markings I can see on the inner race, from the primary side: TTLD and RLS 9-1/14).

I assume this is the original bearing. I did not order a new one yet, as I still don't know for sure it is the cause of the problem. It sure looks OK from my limited vantage point so far.

I will go back to the garage and start opening the gearbox and pulling out the guts.

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

Didn't get too far. I thought Mr. UPS would have shown up with the clutch lockring tool I ordered, but no luck.

Without that I can't go further - will get back to it on Monday.

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

pkeithkelly said:

Didn't get too far. I thought Mr. UPS would have shown up with the clutch lockring tool I ordered, but no luck.

Without that I can't go further - will get back to it on Monday.

Click to expand...

The tool for removing the clutch lock ring from the inner cover does not always manage to get the ring off. It often depends on how much force was applied (and if Loctite was used) when it was installed. You may find a hammer and suitable punch are the best tools for its removal plus some heat.

The sleeve gear is located in the bearing by a slight interference fit plus as you tighten the LH sprocket retaining nut it traps the sprocket, the spacer and the bearing against a shoulder.
The sleeve gear bearing it's self is held by the interference fit between the outer race and the gearbox casing.

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

pkeithkelly said:

Didn't get too far. I thought Mr. UPS would have shown up with the clutch lockring tool I ordered, but no luck.

Without that I can't go further - will get back to it on Monday.

Click to expand...

I made this out of a 1" black pipe coupling. Putting a deep socket through the middle over the clutch release body will stablize it. Use a channel lock or a medium pipe wrench to release or tighten. You can also grind flats on the sides enough to allow for a large Cresent wrench.

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

received the clutch lockring tool today that I had ordered from Rabers so I opened up the gearbox and pulled everything out.

The good news:
Everything was nice and clean. No metal bits and all gears look perfect - no dings or obvious wear. Not bad for 40 years and 27,000 miles.

The bad news:
The sleeve gear bearing came out of its pocket in the shell with no persuasion required. I was anticipating this and ordered a new one this morning from Old Brits. Will locktite it back in, per Fred's advice and put everything back together later this week.

And yes, the layshaft bearing was already replaced, about 3 years and 8,000 miles ago. It seized on me while going 5 mph in a parking lot (lucky for me).


The shell with all the guts removed -


I'll follow Fred's instructions on reassembly.

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

Is there any play between the sleeve gear and the mainshaft? I feel this is the more critical areas to take advantage of while apart. Sleeve gear bushes are most prone to wear, relitively inexpensive and easy to swap out......as long as it is already apart.

Pretty much all other items in the gearbox can be serviced without pulling the srpocket, so go for it while you can.

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

Pete -

Thanks for the heads up. I just read your post and went out to the garage to check the fit of the sleeve gear on the main shaft. Yes, there is some wiggle room. I had ordered new bushes "just in case" when I ordered the bearing. So I will change them.

Next challenge will be to get the old bushes out and the new ones in. Hopefully they will come out without too much trouble, but those circlips look like a pain to get out.

We'll see.

Thanks again for the advice.

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

1. Please do a good check if the infamous crack is there between the 2 bearing recesses.
2. My experience with various types of loctite for this purpose, with "The Crack" present: it will not last.

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

More good news / bad news, although the good outweighs the bad by a wide margin, fortunately!

Good:

- there is no crack between in the gearbox shell between the layshaft bearing pocket and the sleeve gear bearing pocket. Looks perfect, thankfully! That would have been an expensive issue to deal with.

Bad:

- no matter how much fiddling I did with jeweler's screwdrivers and other small tools/hooks, I could not remove the circlips holding the bushings in the sleeve gear. I gave up. I dry fitted the sleeve gear back on the main shaft and have convinced myself that the tiny bit of play between the shaft and the bushes is acceptable (it is barely noticeable).

So now to fit in a new sleeve gear bearing and reassemble.....

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

I found it really awkward trying to fit the sleeve gear bearing with the shell still in the bike, so I took it out. Will put the bearing in on the bench, then put the shell back in to reassemble.

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

pkeithkelly said:

Bad:

- no matter how much fiddling I did with jeweler's screwdrivers and other small tools/hooks, I could not remove the circlips holding the bushings in the sleeve gear. I gave up. I dry fitted the sleeve gear back on the main shaft and have convinced myself that the tiny bit of play between the shaft and the bushes is acceptable (it is barely noticeable).

So now to fit in a new sleeve gear bearing and reassemble.....

Click to expand...

Get a very small grindstone for a Dremel or similar rotary tool and cut into the gear from the bore out to the edge. Just cut the outer part of the bore between the outer edge an the groove that locates the clip. This should let you get something in behind the clip to hook it out. Fit new clips they are cheap an often getting them out damages them.

Re: Final Drive Sprocket -end play on shaft -what's wrong? H

Hold the tool in the same plain as the bore of gear centre line. So you get a tiny semi circle type cut out. Once done any future bush changes will be no problem an there should be plenty of metal to hold the clip in place if you use a 1/4 inch diameter stone or smaller.

This is another tip from Mick Hemmings and is well tried and tested.

Thanks again for the help with my sleeve gear bearing issue.

I finally had thge time yesterday and today to finish up the job.

I heated the gearbox shell, froze the new sleeve gear bearing, and tapped it in, along with a bit of red locktite (hopefully that will keep it in place for another 40 years).

I reassembled the gearbox, without too much trouble, thanks to Fred's helpful instructions on oldbritts.com.

While I was at it, I replaced all the oil seals in the gearbox and primary areas, and even treated the bike to a new set of Barnett clutch plates.

After new gaskets, adding fluids, and checking torque on everything by noon today, I decided I deserved a test run. Did a quick run around the neighborhood to see if I forgot anything. Sure enough, I had forgotten to tighten the clamp between the muffler and the header pipe, which I had removed to work on the primary. Easily fixed.

Then it was time for a 40 mile run through the twisties (I am in North San Diego county, so there are plenty of them around).

The result? S - W - E- E- E - E- T- T!!! Bike riding beautifully and the shifting and clutch as smooth as could be.

Once again, I'm a happy Norton owner. Time for a few thousand more miles and grins!