Steering Bearings

[pandelboy]

Has anyone got any suggestions to get the bottom bearing off the yoke spindle on a 125 gasser. Ive got it in the freezer at the moment and then will try heating the bearing and see if it will move. I havent got any type of puller that will fit so having to knock about with a drift and hammer.

[alan bechard]

Buy the bearing puller or take it to a machine shop and have them remove it.

If you absolutely must do it yourself, and do not want to use the correct tool, a dremel or other small cutoff tool with a cutoff wheel and remove the cage and bearings, then very carefully begin cutting through the inner race. When you get about 1/2 way through and both sides are scored, you can take a sharp small chisel, put it in the slot that you cut and strike it sharply with the other side well supported, ie tree stump or anvil and normally the inner race will shear across that fault line and pop off.

I would buy the puller. Cheap chinese one is probably $10 compared to how much for new stem and lower yoke if you slip?

[boofont]

Not sure about Gasser's but on an SY the spindle pushes out of the yoke. If its the same, (i.e. the spindle is a separate part to the yoke) then push from the top of the splindle and the bearing will be pushed off the spindle by the yoke. Then push the spindle back in to the yoke. The new bearing will be tight but if you heat it first in the oven it will help. Tap it down keeping it as square as possible. To do all the pushing you'll need a bearing press, best bet is to take it to any engineering place and ask them to do the procedure I've just explained.

Edited May 18, 2005 by boofont

[g4321]

I personally would be a bit wary of pushing the steering stem through a yoke to remove the bearing race from the steering stem. I would be worried that this would weaken the fit of the stem in the yoke even if heat was used to expand the alluminium of the yoke.

A puller is the ideal method but finding someone who has one to suit is not that easy.

Carefull cutting using a dremel or equivalent does work - I have used this to remove main brearing races from a weak 2 stroke crankshaft where a puller could not be used.

Using a couple of thin chisels or wedge pressed or hammered (if really rough) between the bearing race and yoke is the one method which is relatively straightforward. Once the bearing race starts moving use a thicker chissel or even screwdriver. I have heard of people removing bearing races by arc welding onto them but I am pretty sure this is really for removing outer races in alloy cases.

[boofont]

It was Nigel Birkett that told me about removing the bearing, I don't suppose he knows what he's doing then?

[pandelboy]

Thanks for all the different advice lads, i have managed to remove late last night. I froze the yoke, stem and then put in the vice and then heated the bearing localy and managed to get a screw driver knocked in at the bottom of the bearing and prized up enough to get two thicker screw drivers either side and prized right off and it came off quite easy. I then put the new bottom one on by putting the whole thing back in the headstock and with the old top bearing in place with a washer on top then put the top plate back on and pressed the bottom one on to the spindle by tightening the top nut and it worked a treat. I know it sounds bodgy but it worked quite well.

Edited May 19, 2005 by pandelboy

[g4321]

HondaRS

ob is so very easy with the proper tools (especially so in the case of an inner race stuck on a crank).

Unfortunately the crank I was refering to is from a 25.7cc Cyclemaster engine and most bearing pullers will not work on such a small diameter shaft & bearing - hence the careful use of a dremel. lets just say its not the heaviest construction motor in the world. I think that using a hammer/chisel would really wreck that one. As for a heavyweight stationary engine or similar then thats a different matter.

Whether I could buy a Cyclcemaster puller after being out of production for over 50 years is highly debatable.

There are times when makeshift methods are the easiest and most practical option, it all depends what you are working on. Glad it worked for pandelboy

If as Boofont says Birkett recommends pressing the stem partially out of the bottom yoke to help remove a bearing so be it, who am I to argue. I wouldnt approach the job that way on my bike.

Edited May 19, 2005 by g4321

[charliechitlins]

Perhaps the easiest way to remove a steering stem inner race, if you dont have the proper tools, but do have a MIG welder, is to remove the bearing cage and rollers, degrease the bearing race, and then weld on a couple of blobs of weld about opposite each other, and before it all cools down use a punch or blunt chisel to hit the weld blobs and remove the race.

If you weld all the way round, it'll drop out as it cools!

I love hearing them hit the floor when I'm off in the corner putting the welder away.

[copemech]

I had to replace mine on the 1.25 Sherco about a month ago. The lower bearing was rediculously tight on the shaft.

After cutting and splitting the old race off, the new one would not go on even after heating the bearing, cooling the shaft and polishing the shaft to remove excess material.

Finally I used the old split race to drive the new one on with a hammer and drift so not to damage the new bearing.

It was more work than I had planned that evening and I ran out of beer too! Real Pisser!

Next time I'll have a proper length of crocus cloth to polish that shaft down to a nice fit (i think it needs about .001 in. removed).

MC

[glenn]

Hi

I was advised by kev the gas gas mechanic that pressing the steerer tube out was the way to go. When i did it on mine, i used a very big vise at work and it came out no problems.

Cheers Glenn