Headstock Bearings

[bazza696]

Just got my headstock bearings out, getting ready to fit new uprated bearings from Wemoto, and found they dont fit. The code on the original bearings are 30055-1 off the top of my head, and the ones that new ones are 32006, these codes are significant, but have I been sent the wrong ones, or are these codes because of them being roller bearings, not standard ball race bearings?

[AMCQ46]

Bazza,
if you have got the taper roller bearing set from WEMOTO then the part numbers on the races will not be the same as the numbers on the standard cup & cone all bearings.

I can tell you the number off the kit when I get home tonight, but the easy check is to see if the inner and outer diameters are the same as the standard bearings, if they are you are good to go.

Note that the taper roller bearings are deeper than the cup & cone, so ignore that dimention, only inner & outer race to compare diameters

[bazza696]

Cheers for that, it was that the bearing codes on the box are different from the markings on the bearings.

Look forward to your reply.

[AMCQ46]

OK , numbers as follows

the kit is HCH-903R [COL001]

the bearings should be
Bottom:- 30 inner Diam by 55 outer diam by 17deep [should be marked 32006] So that is the number that you quoted, so Bottom Bearing is OK.

Top;- 26 ID by 47 OD by 15 which is a special, and not in my normal bearing supplier hand book and I cant remember the number on the part.



The taper bearings have a different numbering system to the cup & cone so I think that is what is causing the confusion, hope that helps and you get them fitted OK.

Also note the setting process [torque preload] for tapers is not the same as for the std balls. The standard part requires a good preload torque [it is in the haynes manual, but I dont remember], but if you do that to tapers you will get a very strange low speed steering wobble, as they will have much too much force locked in. You should set tapers just above hand tight where there is no slack and a slight increase in the torque to turn the steering head.

I do this with the wheel off the ground, and look at how easy the steering is to knock off center, and if the bars will fall to full lock under their own un ballanced forces. if you move the seeering off center and it wont fall to full lock [and it did before you thightened it] then you are too tight.

Also you will find when you tighten the steering stem nut, that will further preload the bearings, so you may have to slacken them off to compensate for this final assembled condition. Always do the final test with the top yoke fitted and the top nut torqued down, then you will have it correctly set.

Hope it makes sense

[Stratman]

Also you will find when you tighten the steering stem nut, that will further preload the bearings, so you may have to slacken them off to compensate for this final assembled condition. Always do the final test with the top yoke fitted and the top nut torqued down, then you will have it correctly set.

That's the bit that anoys me - you think they are OK, then torque down the centre nut and they are too tight! Have to nip mine up a bit before spring.

[Phil-VTwin]

Good info AMC , have you thought about putting it in "The Workshop Knowledgebase" section?

[AMCQ46]

Good info AMC , have you thought about putting it in "The Workshop Knowledgebase" section?

No........... but I will now

[tony.mon]

I'd only add that form my experience you need to re-adjust after a few hundred miles (say 500) as they seem to "bed in" slightly and become a tiny bit loose.
You can then hear/feel a tiny knock as you ride over a ridge or change in surface.

It's the looseness with taper rollers that causes them to notch at the straight-ahead position, and you don't want this to happen a week after you've fitted new ones.

I tried over-tightening slightly at installation to allow for this, but found that the bike was really difficult to ride without gentle weaving side-to-side- which means filtering is much more exciting on the M25 than normal

[bazza696]

I tried the bottom bearing and did not think it was going to go on, so bottom yoke is going in the freezer tonight, and I will warm the lower outer race and try again. Is this lower bearing supposed to be this hard to get on, the manual says that you should be able to remove it with two screwdrivers, my screwdriver plugged in, and the end spung very fast and produced sparks..

[Stratman]

I tried the bottom bearing and did not think it was going to go on, so bottom yoke is going in the freezer tonight, and I will warm the lower outer race and try again. Is this lower bearing supposed to be this hard to get on, the manual says that you should be able to remove it with two screwdrivers, my screwdriver plugged in, and the end spung very fast and produced sparks..

I used the freezer/oven technique too for the bottom race

[sirch345]

the manual says that you should be able to remove it with two screwdrivers, my screwdriver plugged in, and the end spung very fast and produced sparks..

I like it :wink2

Yes, the bottom bearing I found to be a tight fit too. I couldn't remove mine with two screwdrivers as I wanted to save the oil seal (yeah tight git I know). I used my 4.5" angle grinder very carefully to grind down the bearing center making sure I didn't grind away the steering stem. I masked off the oil seal first to protect it from the grinder sparks. Once almost down to the stem I rested the bearing (with the stem) across my slightly open vice, then gave the bearing a crack with a cold chisel which split it. It was then easy to take off.

I was talking to an expert (VTR guru) about how I ended up adjusting my taper roller bearings 3 times in total before I got them set correctly. He said that is the normal for taper roller head stock bearings.

3 times meaning, after first fitting them I covered some miles before the next adjustment. Then coved some more miles before the final third adjustment. Probably around 300 miles between each adjustment.

The final adjustment I only moved the castellated nut about 3mm

Chris.

[AMCQ46]

I tried the bottom bearing and did not think it was going to go on, so bottom yoke is going in the freezer tonight, and I will warm the lower outer race and try again. Is this lower bearing supposed to be this hard to get on, the manual says that you should be able to remove it with two screwdrivers, my screwdriver plugged in, and the end spung very fast and produced sparks..

My bottom race was very hard to remove, I used same method as Sirch345, but I had the new seals in the WEMOTO kit, so I wasnt as careful with my grinder. You can see part of the bottom seal & race past the bottom yoke, and you have to beat the crap out of this with a good quality punch. Also take care not to damage the thread on the end of the spindle when you are driving the bearing off.

Fitting:
1) use freezer / oven method, ..........use the old bearing as a spacer so you dont hit the new bearing................get a length of tube which is correct diameter to go over the steering tube and make good contact on the back of the old bearing. [I used the upper part of an axle stand, as it was long enough and correct diam]..........then it is back to the hammer and keep going till the seal is trapped and wont rotate .

it is a brute force project, but still take care not to damage the bearing or the spindle threads.

Good luck

[bazza696]

This is like more of the black art, similar to the black art of starting a storm....Does this make us all wizards, or demons?

[Stratman]

This is like more of the black art, similar to the black art of starting a storm....Does this make us all wizards, or demons?

[tony.mon]

Use the force, Bazza,















and a bloody great hammer