Taper Roller Ring Removal

I am in need of some more suggestions from all you resourceful guys! I have an old motorcycle that I need to replace the taper roller headrace bearings on, and there is a problem: the bearing rings in the headstock have barely any lip showing to get a punch on.

I have done this job previously on a similar frame, and found that the only way was to grind through the rings and break them in two, but I really do not wish to go through that again. I know that the easiest way would be to run a ring of weld around the rings to shrink them, but I do not have access to a welder. Also, due to the design of the headstock, it is not feasible to drill two holes through from the outside and punch the rings out; which leaves me with the idea of grinding a recess above the ring on either side, to give enough room to get a punch onto the rings.

Can anyone offer any ideas on this? I plan to use a Dremel with a small grind wheel and, holding it vertically, grind a recess above the ring. Unfortunately, these rings are extremely tight in the housings, and take a lot of force to move, so I need to get good purchase on them. Any advice would be gratefully received!

Cheers,

Colin

Using a borrowed welder or taking it to a welding shop is probably the best way. But maybe you could cut some grooves in the race parallel to the faces of it, halfway up, deep as possible, and use a clutch pilot bearing puller or similar. Cutoff disks in a Dremel type tool could do this. You also might try using a CO2 fire extinguisher to thermally shock the race before pulling it.

Some races are in housings whereb vthere are two recesses behind the race where an extractor could be used.

Sykes Pickavant usewd to sell an extractor with "legs" for such events. The "legs" were forced outwards by means of a screw thread, so that they did not slip.

maybe you could make something similar thast you could then either punch out, or less violently use a screw therad to pull out.

The new races could then be pulled into place with a "dolly" in place of the legs.

Howard

One way that may work if you have a lathe is to turn a steel disc about 1/8" thick to the exact size of the headstock bore inboard of the bearings, than saw two flats opposite one another to make one axis slightly smaller. The object is to Set the disc against the bearing and it will stand careful drifting as it cannot slip out of place like a drift on its own. A central hole would make it easier to turn on a nut and bolt.

Thank you.

In the past I have used a thick washer that fits exactly against the bush to be removed, sawn in half, and the two halves butted up against the bush or bearing ring, allowing a piece of tubing to bear against it. So, the suggestion of a steel disc may work, but the lip of the bearing available is tiny, plus the bearing rings are very tight, so the disc may not get sufficient purchase.

This is one thing that may work if you can get it to be the best possible fit and also be able to rotate it. Even a tiny difference in diameter would guarantee purchase as the disc has nowhere to go. The best pusher would be the largest tube or bar that would fit as it pushes evenly all round at once. With a tube just bigger than the OD of the bearing ring, you could use a length of studding, washers and nuts to pull the ring out.

 By the way, what bike are you working on?

Edited By old mart on 10/08/2023 20:02:13

Thank you, that is the best suggestion so far and may just work. The last one that I replaced the bearings in was a nightmare, as the rings were almost welded in the housings and all the hammering did not do my aged fingers any good. I am not planning to do the work until the Winter, so it will give me time to sort out the parts.

The bike is a Spanish Ducati 350, and I don't think that future maintenance figured very high up on their list of priorities when they built the bike.

Cheers,

Colin

I fancied one of those 350's.

It is a nice bike and good fun, but like all old vehicles there is always something to be done. Still, it is a hobby, not everyday transport.

I am not clear as to the exact configuration, but I have managed to extract bearing outer tracks by using a suitable size rawl bolt. A split ring can be made up if necessary to fit between the rawl bolt outer and the bearing inside diameter, and aluminium is good for this as it will indent to help with grip. Discard the actual bolt, and substitute with the right size of screwed rod that fits the expander thread. Fit a nut to the other end to actuate the expansion and tighten this well. The tail of the screwed rod then goes through a suitable size sleeve (often one or more pieces from a socket set can be used), then a washer and nut to do the actual extraction. Clearly it depends on sizes and what you have available.

Not sure of the bore sizes but I used to remove the thrust bearing in blind holes in the back of a flywheel using:

• a Rawlbolt expanding masonry bolt screwed into the hole and tightened
• a slide hammer with a crude adapter to attach it to the Rawlbolt.

I wonder if you could create a similar arrangement to a) grip the bearing and b) slide hammer it out?

Hopefully some food for thought.

Simon

Usually if I get a head race that I cant get a puller behind or a drift the only way I have found successful every time is to run a bead of weld around the inside of the race allow it to cool and the weld will "shrink" the race and more often or not will fall out have also used this method to remove valve seats. 

Edited By Paul Mills 4 on 10/08/2023 21:35:37

Thanks for all the suggestions, they are all being stored in my brain. There is no doubt about it, many heads are better than one.

Cheers,

Colin

At my Son in laws place. Bike tyres Leeds they have a expanding mandrel & slide hammer . I have seen them using it to pull wheel bearings out of bike wheels. Probably a Sykes pickavant item. Works well. So some of the above would work by making a expanding mandrel yourself & fashioning up a slide hammer.

Steve.

That works in bearings with a parallel inner bore. It would struggle greatly in the outer cup of a taper roller bearing as there is virtually nothing for it to expand against.

It would be similar to closing a 5C collet with nothing inside it - likely to damage the tool.

Total tangent but I am fascinated by Malcolm having exactly the same thoughts as I did regarding Rawlbolts but he typed quicker than I did. I only saw his response this morning reviewing last night's messages! How do you spell 'coincidence....?

I have removed the taper bearing outer races from 2 BMW motorcycle headstocks largely in the way you suggested that you did this previously - by making multiple cuts into the race with a Dremel thin cutting disc (well several of these discs - they don't last long ! ) being careful not to cut into the frame. Then, with the outer race suitably weakend, a couple of blows with a drift & substantial hard hammer cracked the race into sections allowing removal. Not a fun job !

There is a special BMW tool to get hold of the minimal available lip that protrudes into the bore of the headstock - but I didn't (and still don't ) have access to one of those.

MZ TS250/1s are so much easier - just a couple of 6006 ball races with a spacer tube between them, a similar arrangement to wheel bearings.

Nigel B.

the bearing rings in the headstock have barely any lip showing to get a punch on.

”Barely” means there is some. Use a full diameter drift. Problem likely solved at a stroke!

Guzzi swinging arm bearings are like this, If you have a local Cat agent they probably have the specific puller. I managed to get a set of Guzzi factory tools from an agent no longer servicing them (Kings of Birmingham) years ago. The 'Puller' basically looks like a collet. Three splits and a threaded bore, the split end a smaller bore to allow the threaded rod to expand the working end. Working end O/D is the same dia. as the smaller end of the race and the main body reduced to form a lip on the working end. When inserted and tightened into the race, a 'Jacking' sleeve is placed over the assembly, bore of which is greater than O/D of the race, washer over the top and a nut screwed onto the tail of the threaded rod.

Slight heat o the housing helps when drawing the inner out.

Regards Ian.

Colin, If your anywhere near me (N Norfolk ) your welcome to borrow a small welder ! Seldom seen, I have a hollow hydraulic cylinder with a 1"bore(ID) that is invaluable for pulling things apart. Noel.