Layshaft Stuck

Finally getting around to checking the layshaft bearing on my 74 850 MkII. I haven't had any problems with the gearbox or kickstart but heard enough stories and the PO didn't know if it had been done. The bike has 31,000 miles. I'm using the techinque form the Workshop Companion site, Old Britts and the manual, read posts etc. I am doing it in the bike and have it disassembled to the point to heat and pull. I put the heat to it using a 1500W heat gun for about 15 mins, grabbed the shaft and pulled, no go, could feel the heat thru the glove, gave it more heat and pulled with plumbing pliers wraped in cloth, no go! Whats next? Heat the absolute crap out of it and keep pulling, use a torch? Puller? Don't like the idea of hooking onto 3rd or 4th lay and damaging something. Any advise would be appreciated !


Gearbox ready to pull layshaft by niagaraz, on Flickr

When the case is heated sufficiently it should release the bearing (alloy expands at a higher rate than steel). It seems you haven't got quite enough heat to it yet.

Personally I'd use a torch rather than a heat gun.

It's much easier if the primary drive is removed as the heat can then be applied to the outside of the case directly behind the bearing.

A torch or a heat gun either one. If you use a torch just make sure you keep the flame away from the gear teeth. It is easy to damage the surface hardness. When a wet finger sizzles on the metal then it is hot enough. Jim

Thanks gents, more heat it and patience it is

While I'm at it, here is the kickshaft pawl. Is the waer ok or should it be changed


Kickstart shaft Pawl by niagaraz, on Flickr

I would re-use it. Jim

Sounds like you were heating the SHAFT. You need to be heating the tranny case to get it to expand and release the layshaft bearing. Keep the shaft as cool as possible.

I would re-use it. Jim

Click to expand...

Thanks Jim

Success!! More heat and patience as noted and as repeated in other threads. It took a good 45 mins with the heat gun and finally popped out. This is what I have, a roller bearing without markings. It doesn't look like the pictures of the Portuguese bearings I've seen?


Layshaft Bearing by niagaraz, on Flickr

To replace, do I take the layshaft gears and bearings and put them in the freezer overnight. Then heat the case for a good 45 mins and push the frozen shaft back in and reassemble?

Mike

I think I was wrong there it appears to a ball bearing

The bearing looks like it has a steel cage. The factory bearings usually had brass cages so that one may have been replaced already. The factory replacement bearing is a roller.

I wouldn't try heating or cooling to get it on and off. The size change will be so small it will not be worth it. Just use a puller or tap it off by working around it with a punch and hammer. Protect the gear with a cloth wrapped around it.

You can tap the new bearing in place on the shaft with a small hammer also. Just don't hit the outer race when your installing it. Use a socket or something similar to contact the inner race only.

Then after the case is good and hot again slide the bearing and shaft home in the case as an assembly. Make sure it is good and hot with your wet finger. You don't want it to get halfway home and then stop. A little oil on the outside of the bearing helps with sliding it in. Jim

So I should replace it and not try and reuse it?

Any of the ball bearings have a somewhat limited life. A good ball bearing may last a long time but a roller will darn near last forever if it doesn't get damaged by contamination. I would do it now and never have to worry about it again.

Put a bit of epoxy over the hole in the inspection cover while it is off. There is plenty of room for the trans to breath through the clutch cable hole and the hole in the cover just invites water and rusty internals. Jim

There may be ID markings on the other side. It may be a Hemmings ball bearing, he seems to prefer them, that's what I used. You and most are lucky. My layshaft came out without the bearing right off, and I had to pull the bearing, which can be done. I made up a little puller.

Dave
69S

Niagara850 said:

I would re-use it. Jim

Click to expand...

Thanks Jim

Success!! More heat and patience as noted and as repeated in other threads. It took a good 45 mins with the heat gun and finally popped out. This is what I have, a roller bearing without markings. It doesn't look like the pictures of the Portuguese bearings I've seen?

Layshaft Bearing by niagaraz, on Flickr

To replace, do I take the layshaft gears and bearings and put them in the freezer overnight. Then heat the case for a good 45 mins and push the frozen shaft back in and reassemble?

Mike

Click to expand...

Please keep on posting pictures of your progress as I will be doing the same procedure for the first time very soon with a roller bearing.
It is the shimming part (if needed) that I'm the most anxious about!!! And then the state of the bushings and the gears... We'll see.

If your layshaft bearing is still intact you can save some work by measuring the end play of the kickstart shaft before you take the trans apart.

You can use feeler gauges to determine the endplay by measuring the gap between the kick lever and the cover with the shaft pushed in and then again with the shaft pulled out.

Then you know what thickness of shim you will need to place between the kickshaft and the inner cover before you put it back together. The exact endplay is not critical. Anywhere from .005 to .020 will work. I shoot for .007 to .010. Jim

by SGOUD2 » Tue Mar 13, 2012 10:56 pm
Please keep on posting pictures of your progress as I will be doing the same procedure for the first time very soon with a roller bearing.
It is the shimming part (if needed) that I'm the most anxious about!!! And then the state of the bushings and the gears... We'll see.

Click to expand...

Shimming was something I was also trying to avoid. I don't have a dial guage and having to find shims. My kind neighbour is a shade tree mechanic and lends me some of the odd one time tools I need (his speciality is Jeep). Everything else looks good in the gear box with a little wear. Take a look at the Norton Workshop Companion and the links to the Old Britts web sites. Go through them all, and search the threads, they are very good. Kudos to David and Old Britts for making them available http://www.doov.com/apps/nortoncompanio ... s&Itemid=8. It takes a lot of heating if its done in the bike , much more than I expected, probably because the shaft is getting heated too. Heating the journal area from the back of the case, (remove primary case / remove gearbox) is probably faster if you don't consider the time to take all that stuff apart. I generally try to disassemble as little as possible. Digital camera's are great, I take lots of pics, helps me to put things back together.

by DogT » Tue Mar 13, 2012 10:50 pm

There may be ID markings on the other side. It may be a Hemmings ball bearing, he seems to prefer them, that's what I used. You and most are lucky. My layshaft came out without the bearing right off, and I had to pull the bearing, which can be done. I made up a little puller.

Click to expand...

Yuck! The existing bearing looks good, has a steel cage, spins smoothly and shows no sign of corrosion or wear. I'm leaning to replace while I have it out, now to weigh the pros and cons between roller and ball bearing, both have their merits.

Put a bit of epoxy over the hole in the inspection cover while it is off. There is plenty of room for the trans to breath through the clutch cable hole and the hole in the cover just invites water and rusty internals. Jim

Click to expand...

I took a closer look at the inspection cover and hole has been previously sealed. What is the purpose of the threaded brass tube on the inner cover close to where the clutch cable comes in the outer case? Breathing hole? I expected to find the bearing replaced when I saw the inner case was previously marked to line up the clutch lock ring, the pencil mark on the case edge is mine.


Inner cover by niagaraz, on Flickr

regards, Mike

Niagara850 said:

by DogT » Tue Mar 13, 2012 10:50 pm

There may be ID markings on the other side. It may be a Hemmings ball bearing, he seems to prefer them, that's what I used. You and most are lucky. My layshaft came out without the bearing right off, and I had to pull the bearing, which can be done. I made up a little puller.

Click to expand...

Yuck! The existing bearing looks good, has a steel cage, spins smoothly and shows no sign of corrosion or wear. I'm leaning to replace while I have it out, now to weigh the pros and cons between roller and ball bearing, both have their merits.

Click to expand...

The "Hemmings" ball is a high quality FAG 6203TB Phenolic (T "Textile") cage bearing. The standard ball bearings fail because the metal cages eventually begin to break up.

Niagara850 said:

I took a closer look at the inspection cover and hole has been previously sealed. What is the purpose of the threaded brass tube on the inner cover close to where the clutch cable comes in the outer case? Breathing hole?

Click to expand...

Yes, it's a breather mod. http://www.oldbritts.com/12_065199.html

That breather mod is also factory on late model bikes. Put a hose on it long enough to point down or it will pick up rain.

The replacement ball bearings will also fail eventually from brinnelling of the inner race due to the high load. No sudden failure -they just get noisy. Jim

Did some checking today, e-mailed Andover-Norton in error thinking they were Mick Hemmings... I had too many windows open... apparently Mick Hemmings doesn't use e- mail. I used part no 04 0100 from the Parts List, Nick Hopkins replied with an updated number 06 7710 which is a roller bearing for 27.50 pounds. Sent my usual supplier - Walridge a note also. He has 2 bearing listed, one for $19.92, not specifiied and the other is a Super blend roller for $47.50. I asked for clarification and haven't heard back from him.

I looked at the current Mick Hemming price list and didn't see a ball bearing listed, just a roller. Maybe it isn't available anymore. Anyway is old reference cataloge has this listing

Layshaft Bearing (Standard Type) O4 0100 3.13
Roller Replacement for above (Not recommended) 06 7710 16.25

A confusing choice of wording?

The superblend type bearing has a brass cage and is the premium option. Most likely the cheaper bearing is a polymid cage. That is what I normally use. Jim