Main Bearings

I've searched the forum, but really didn't find an answer. How do you correctly remove and replace the inner races for the main bearings. I can do the outers, no problem. But what about the inners? Do you heat them and then pull with the puller or do you just pull cold? Do you have to have them pressed back on or do you heat and drive them on with a section of pipe or tubing? I'd like to do this at home, but will take to a shop if I need to.

-- David

Hi

I pulled mine off cold as long as the puller can get behind, it will take a bit of tighting but you will hear it when it releases and I used the old ones to knock the new one back on.

Ashley

Wasn' t that difficult when Crazy was fitted with the superblends. Just tapped the inner race home over the crankshaft ends being carefull to tap home evenly all the way round. Do not under any circumstances apply heat to any bearing or inner race of such. Yes you found out about heat to the cases to drop in the outer mains cold . Good. Peter.

Thanks - it sounds pretty straightforward. I guess I'll find out next week.

Support the crank under the Flank / Web / counterweight - mainshaft installing .So you dont stress crank pin .
If pressing on go easy till its got on square before applying full wellie .Oil under will stop corrosion under done dry .

yes a good sharp bearing separator gets the inner's off, DS is firmest. I had a mates hydraulic puller, and to install new inner's I rigged up a tube and with the puller claws under the crank web I was able to push on the inner bearing nice and easy, nicer than banging on a piece of tube. Tube needs to be 30mm clearance. And I machined a cap so the puller had a bit to push on. Outer's drop in with the cases at the right heat, I put my cases in the barbecue under the hood, easy.

Shims for end-float are best put under the TS inner as it is easier to withdraw if you have to add or subtract to get 5~10 thou.

Cheers Richard

There is Norton factory service tool for this that works as it should. It is a "Pickavant" type of puller. You will notice the inner superblend race has a groove separating where the rollers bear from the flange that buts against the crank throw. This factory tool grips the race right there and plucks it right off.

This tool is marked "Norton 06 3970. My guess is that Norton had Pickavant assemble it for them to order from puller components out of their catalog. You may be able to get an equivalent from Pickavant still as I am sure they are still in business. Besides pulling inner races off Norton cranks, I have used this to pull a friend's seized wheel bearing off a trailer axle, and I have also put a plate over the bottom part of it and used it as a mini arbor press.....



As far as putting the inner race back on, support the crank throw directly behind the shaft and drift it on with a brass or alloy drift bored out to a little bit bigger than I.D. of the inner race....

Got a factory service manual for your bike???

Beng,

Thanks for the pic. I do have a manual, but it doesn't cover how to get the race back on. Section C19 shows the tool and mentions how to remove, but I didn't really find anything about installing a new race. I also haven't done this before so I thought I would ask first.

I got one of these http://www.amazon.com/OTC-1122-Bearing-Splitter/dp/B000O866WE/ref=pd_cp_hi_0, which I'm assuming will do the trick. Thanks for the help!!!

-- David

David,
You can heat the inner race to put them on. I've found that heating it up in an oven to around 250F has worked for me. I'm not saying you need to go out and get one of these, it's just to show that it's common practice to heat races to install them.
http://www.conemount.com/?gclid=CKTk2L3 ... gwod9RUy6Q

Bearing fit onto a shaft is never that tight, and if you can find a piece of tube of the right diameter, simply put a smear of grease onto the shaft and tap the bearing race home.

An old used oven would be a nice addition to the garage. Never really considered one before. Of course, I've been divorced. Three times.

I was thinking an old dishwasher might be good for degreasing too!

When Noah was a boy , they used a 44 Galon ( 50 US Gal. ) drum , filled with caustic potash solution , out the back .
Gives off hydrogen or something . Of course everything was made of Cast Iron then .Dunno if its safe for Al oominum .

Actually picked up in a 70s Aussie vintage & restored cars mag , thats Still Published . Serious Aussie Journalism . :shock:

Try not to wind your beareing splitter into the mainshaft . To avoid Burrs and Stress Raisers / dings .

Likely the inner will slide o.k. once shifted , so judicious levering / prying , equaly from 3 sides should have it off.
Or hit it with the Propane torch if its recalitrant .

Fitting , its only if you went over 600 odd degrees that youd affect its molecular integredy , hardening or stability .
250 in the oven , if the missus is out , with the oven door and windows open for a hour before she rematerialises ,
provideing theres ' none off that nasty oil ' to leave a odifourous trace .What they dont know doesnt get an ear chewed .

Pays not to hurry , to get ' heat soak ' . Leather Gloves etc , but youll need the tools at hand, so put plenty of paper down .

JimC said:

An old used oven would be a nice addition to the garage. Never really considered one before. Of course, I've been divorced. Three times.

Click to expand...

Check Craigslist and Free stuff, something always turns up.