Can't get the new tranny mainshaft bearing mounted (2010)

I have the tranny out - but so far I have had no luck at all getting the new mainshaft bearing in place. The new layshaft bearing was easy. I have attempted it 3 times so far to get the mainshaft bearing in, each time heating the case to 350F in the oven and cooling the bearing in the freezer but the bearing just will not press into place - either with a screw-type "press" or using a large socket as a drift. It will go in a bit and then just lock up. I'll keep at it but was wondering if there is something I'm not thinking of here...

ALSO but unrelated - the new layshaft roller bearing is made in India. Not sure I like that but that's the AN part nowadays. The old layshaft roller bearing, which looked fine but I decided to replace it as part of the rebuild, was a Steyr, made in Austria. I realize I sound prejudiced byt a bearing made in Austria sounds better to me than a bearing made in India. But heck, nowadays, crap comes from everywhere so who knows.

The bearing should just drop in, it shouldn't need even a tap, and in my experience if it sticks then the heat transfer occurs so quickly that it will lock. Is there a burr or ridge in the housing ? Are you using bearing fit ? I would very carefully take a scraper round the housing to make sure that it hasn't picked up and try again. It really must go in square first go.

What make is the Indian bearing ? Assuming that it's not counterfeit then I'd trust a make these days rather than a country of origin.

I had a beee-atch of a time getting my main bearing in. It kept cocking ever so slightly in the bore and jamming. After repeated attempts I realized my bore was slightly out of round, so the bearing was hitting on two sides and forming a teater totter sort of effect. I carefully took emery cloth to the high spots to work them down but only on the edge of the bore so that the bearing would start but I was afraid to remove material toward the seated position. This did it for me. That and I made a screw type puller that centered the puller in the bore so I could have my best shot at keeping it lined up. I cut a disc of hardwood that I could pass all the way thru the case, but just barely. It had a hole centered in it to accept a half inch bolt. Then I backed it with a plate of steel on the outside of the case. By passing the bolt thru this it centered it in the bore. Then I got the bearing started a bit, put a round plug in it to center the bolt, backed it with a plate, put on a nut and started tightening the whole thing down. It took longer to figure this out than it took to actually do it. My biggest problem was keeping the bearing square to the case. If somebody has a hydralic press handy it would make real simple work out of it!

Good luck,
Russ

Mike — did the old bearing come out easily with some heat? If it did, then the new bearing should plop in at that temperature (approx. 170 C or you could try heating it to 190 C). You should not need to press the new bearing into place. Just to be sure, measure the new against the old bearing outside diameter. If they are the same, then there could be a slight ridge from the bearing being knocked out cold or more likely, knocked in slightly cocked. It doesn't take much to create a ridge that will stop the bearing sitting down properly.

If the casing is hot enough, I hold the bearing with my middle finger in the ID of the bearing as parallel to the hole as possible and it should slip down easily, but you have to be quick. If it cocks, stop immediately, tap it out and start again. Don't force it.

Your finger should tell you if there is a ridge. You can check if the hole is out of round with a spring-out and a good vernier calipers or micrometer. I have had to use a scraper and fine emery occasionally with a stubborn bearing. Or it might just not have been in the oven for long enough.

Good luck and tell us how you get on.

Thanks guys - I checked and there is a bit of a ridge so I'll address that and see what happens. The old bearing had to be driven out even with the case heated but it probably wasn't heated as much since I removed it with the tranny in the bike, heating it with a torch. I decided to remove the case from the bike yesterday because I was more comfortable with the assembly being done on the bench.

I'll remove the ridge and also heat it up a bit more and let you know!

I used to be a steel buyer for a bearing manufacturer, bearing manufacture is fairly std and one SKF factory makes bearings as well as any other. For the global brands like SKF what does make a difference is the steel used, even if fully inside the specs the level of inclusions has an effect on bearing life, these inclusions are from the main steel furnace and German steel is the best with really low levels, currently chinese and indian steel are well down in quality for inclusions. SKF know this and you have to hope they import low inclusion steel to india or screen the indian steel they use.





if it was my bike I would put the austrian bearing back in.

Forgot to answer the question - the new AN layshaft bearing is a Fag (India)

"if it was my bike I would put the austrian bearing back in."

I'm thinking about that...

I had the opposite problem with my 850 gearbox. Mainshaft bearings both dropped right in, but I couldn't get the layshaft bearing in. It cocked in the bore and got stuck. I destroyed it getting it out. I dealt with the problem by purchasing another bearing and sending it and the housing to Jim Comstock, who has a bit more experience with these things than I do. He got the bearing in, no problem.

Mike, I think I'd put the Austrian bearing back in also...

Debby

A little more heat and it dropped right in. Per the oven thermometer (who knows how accurate it is, anyway), 350F didn't do it but 375F worked perfectly!

But another bearing "concern" - the mainshaft bearing that goes in the inner cover has pitted rust spots on the outer race surface where it bears against the cover. It's an SKF, England. I figure that the rust spots can't hurt anything but it's another thing that bothers me re how parts are sourced. I've bought lots of bearings in my life and never got a rusty one out of the box. However, the rolling motion feels very smooth, I'm not worried about it. So, one bearing with rust and one bearing from India. I don't think there's anything to worry about.


If not, why do I keep bringing it up?

Hmm, out of round bore was interesting tid bit for me to keep in mind, but mainly posting to say I told ya so about the cockeye'd boogers needing frying pan heat for happiness some times, so often in my case I just take it to HI heat 1st time every time now. I may need to ask to borrow that fancy wood core puller in tool.

If just ordinary sane almost legal riding planned stick in the Indian bearing but if you like to use em up rev'd to red line in lower gears ... I'd bite bullet and hunt NOS from European foundry.

Here's the pic of the new Fag (india) and the old Steyr (austria) and a pic of the rust on the side of the new inner cover bearing.

Since I am getting into my tranny real soon I have a couple of questions Mike:

What year and model is your bike? I'm interested to see what year and model would have the Austrian bearing.

What was the make of the layshaft bearing?

Did you like taking the tranny apart in the bike (did it help you remove the tough to remove nuts) and then taking the case out for reassembly? How would you do it if you were to start over now?

Mike — glad you have it sorted now! You are fortunate that it's tight, because that bearing can work loose in the housing. It was loose on mine and it is now installed with Loctite Bearing Fit, which I dislike having to use.

ANd my next question...

Well, the bearings are sorted BUT...I have had no luck trying to pull the non-floating bushings from the tranny gears. I rigged up a little screw puller but ended up just bending the washers I was using to fit the bushing/clear the ID of the gear, and pull it through. Any tips re this? would heating the gear help or will the bronze expand more than the steel gear?

Answers for Yellow_Cad:

THe bike is a 73 Roadster. There is some evidence that the tranny has been gone into at least partially before so I can't say if the Steyr brand Austrian layshaft bearing was original or not.

I think disassembling the tranny on the bike is easier because it's easy to loosen bolts, then remove the case to do the bearing work. I would do it the same way again. Pulling the tranny - either entirely or just the case - is not difficult and you can do the whole operation with the bike on the side stand.

Re: ANd my next question...

MexicoMike said:

...I have had no luck trying to pull the non-floating bushings from the tranny gears. ..

Click to expand...

Are you working on the sleeve gear ? If so, find something that is a good fit and press/drive them out. If it is the kick start bush, threading it internally (5/8" NC ? ) usually works. Maybe you need something heavier than the washers. I think I used a close pipe nipple and a reducing coupling.


[/quote]... I can't say if the Steyr brand Austrian layshaft bearing was original or not. [/quote]

I didn't think that any Nortons came from the factory with roller layshaft bearings. If I'm wrong someone will be along with the correct information shortly.

Greg

Only try heating the bushes if you suspect that a previous owner loctited them in. It should not take much heat and direct it at the bush and not the teeth and not for too long. I replaced second and third gear pairs, and one of each pair were floating, while first gear lay is definitely a press fit. Try matching up a socket that is marginally smaller than the bore of the gear. Get a much larger socket for the other side, to clear the bush as it comes out. If you have a bench vice, use this to press the small socket inwards and this should shift it. If no vice, a bolt should catch in the small socket and use a nut and washers on the other end as you have been doing. If the washers bend, use a large nut instead.

MexicoMike said:

Here's the pic of the new Fag (india) and the old Steyr (austria) and a pic of the rust on the side of the new inner cover bearing.

Click to expand...

I know it was a long time ago since I worked on a Commando gearbox, and fitted a roller bearing for the layshaft, but shouldn't that bearing have a lipped inner race ?
The inner can be slide fit on the end of the layshaft so there's nothing to stop the race moving out and rubbing on the case, creating debris.
Also, endways float of the layshaft assembly is increased as the layshaft 4th can now rub on the outer race.
Should the bearing have 'NU' prefix rather than 'NJ' ?

marston rhode said:

but shouldn't that bearing have a lipped inner race ?

Should the bearing have 'NU' prefix rather than 'NJ' ?

Click to expand...

We have only been shown one side of each bearing. NJ is the single lipped bearing prefix.

That Indian bearing is at least the high spec. FAG X-life type.

Here's the other side of the two bearings - new (Fag) on left

Reassembled the tranny with all new bushings. All the bushings fit just fine with no reaming necessary, The only bushing I had a real problem removing was the kickstart shaft/layshaft bushing. There was no way to access the bushing so I cut two slots in it with a hacksaw - one slot all the way through the bushing to the shaft metal so it could compress and then I was able to pull it out by just "turning" it out with a flat piece of metal, like a big screw driver.

Needed several shims to produce .005 end play on the layshaft. Tranny had no shims previously and I didn't check it on disassembly - had to have been too much...

Here are a few pics

Cutting the slots in the kickstart shaft bushing


the Parts


Sleeve gear in place. The red liquid is ATF, which is what I will be filling the box with. I had decided that if I put in NEW bushings I would use ATF; If I had to use the old bushings I would go with gear oil.


Assembled/checked to see that all gears work OK - mainshaft nut not installed yet in the pic.