Early Commando tapered rollers

Hi Steve,I assume that you have cleaned all paint out of the bearing diameters and the seat is clean and no burrs? I also suggest that you check the bores are both round within less than 0.001 inch. If not the bearings will always feel "lumpy". I use two flat discs with a stepped diameter just under the bearing o.d, and deep enough to seat the bearings. I drill a hole through each, and use a length of 12mm stud to pull them in together. Do not forget to to put open ends outwards. Hope that is helpful. regards, Paul

Hi steve

in addition to Paul's post I would freeze the outer races to shrink them a bit. You can also gently warm the bores with a hot air gun. You won't have to heat it much to make it easier to fit the races.

Dean

The bearing outers should tap into place with an alloy or brass drift. I doubt that the bores in the frame will be round within 0.001" because the headstocks would have been machined prior to welding in place. As Paul says though, you need to remove all of the powder coating from the headstock bores (unless you masked it properly) but don't go at it with a flapwheel or the like.

because the headstocks would have been machined prior to welding in place

No idea how it was done on the Commando but I have a picture of the Triumph/BSA OIF in completely finished welded form loaded into a machine that then machined the headstock bearing housings. Meaty looking machine too.

That would be a good way to do it but the Triumph factory was a different kettle of fish compared to the Norton works from what I've heard. A friend of mine has a Rob North framed rocket three racer and he says his headstock bearing housing is way out of round.

Previously stephen_froggatt wrote:

Thanks guys very helpful I got Tripple s to Powdercoat so bores are clean , bearings in fridge next to beer !! As there is only one top Crome nut is there a torque setting or is it tighten up then back off a certain amount. My workshop manual doesn't cover early commandos very well. Thanks again Steve

steve

I've looked at my manual which covers commando models 1970 onwards, It states that the 71 and later head bearings are non-adjustable because the bearings butt up against a spacer tube. ( steering head main nut torque 30ft./lb)

hope this helps steve

Hi Steve

fitting tapper roller brgs to a frame the pre-load on the brg is set by how tight the retaining nut is... Like the wheel brg on a stub axle. So the nut should be tightened then backed of till steering turns freely without any slop.

this can be hard to do if triple trees are later type with course tread on steering shaft. The best type is the fine thread type from the featherbed frame.... Early commando. I don't know when they changed over? I'm sure someone will let us know....

you could still use later type if that is what you have but I would say that you will need to lock the nut with a tab washer or something to stop it loosening.

i am planning tapers instead of the loose balls on my 1968 commando but this has fine thread.

hope this helps

D

My 1971 registered Fastback has featherbed type yolks (triple trees) though the build date was probably mid 1970 "one chrome nut" would indicate to me the featherbed yolks. beneath the top yolk is a threaded collar to adjust the play on the bearing then the top yolk is fitted and the whole lot is nipped up with the chrome dome nut. when you nip it up the whole lot tightens a bit too much so you have to do it again, and again. Ride it for a hundred miles over the roughest roads you can find, (not difficult in UK) then repeat the adjustment before taking it for it's MOT.

You can get a slim sykes pickavant water pump spanner and file it to fit the threaded collar. get another for the stanchion top nuts and the big sump plug.

Steve, your shoulder nut is the the way ahead, maybe this is missing from your Commando