Headstock bearings

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mizzytheman
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Joined: Tue Dec 28, 2010 1:17 pm
Location: Knowsley, Liverpool

Headstock bearings

Post by mizzytheman »

Hi All,

Has any one got ant advice on Taper headstock bearings. I installed some bearings I purchased from PKN (ebay). After fitting I found there was a small amount of horizontal and vertical play in the top and bottom yolk. I spoke to PKN who asked me to check the sizes printed on the bearings. You can't do this on the bottom one unless you remove the bearing. Oops, broke it trying to get it off. PKN kindly sent me a new set free of charge along with seals and said that should sort the problem out. To cut along story short it didn't. I mentioned that some other manufacturers produce a thicker top bearing but PKN said they only stock that size. I have been told these bearings will fit but you have to modify the shaft please see attachment.
Kind regards

Martin
Headstock.jpg
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camper

Re: Headstock bearings

Post by camper »

hi

i have just done mine the bottom one is bigger than the top,my bearings did not come with no seals,nor does it show seals in the books only a black dust seal goes over the top bearing,i might be wrong but all i done was to knock on the outer races the bottom taper bearing just pushes on with a mallet and the top one drops on nice after greasing then just tighen them up.
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yeadon_m
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Joined: Sat Jan 02, 2010 7:10 am
Location: Canterbury Kent

Re: Headstock bearings

Post by yeadon_m »

Hi Martin,

Generally, you DO need to make a tiny mod to the upper part of the steering stem, the section that runs through the top bearing. Otherwise, when the top nut is bolted up, the distance between top and bottom yokes is 1-2mm greater than stock and your headlight moves around.

I have done two and the second time I just used a dremmel and a hardstone to grind the upper steering stem diameter until the top bearing was a tight sliding fit (done with steering stem on bench for ease), then assembled - all is well.

The tapered head bearings are a good change. Makes front end feel more connected!

Cheers,
Mike
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mizzytheman
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Joined: Tue Dec 28, 2010 1:17 pm
Location: Knowsley, Liverpool

Re: Headstock bearings

Post by mizzytheman »

Thanks for the info guys and Happy new year.

Think I'll go and dig the dremmel out the shed and have a go while the missus cooks the dinner

Regards

Martin
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mark.read3
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Location: Great Barr , Birmingham
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Re: Headstock bearings

Post by mark.read3 »

yep, had to do the same with mine, although iwas a bit more brutal and used an air tool wizzy wheel.
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Bluehazebrakes
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Location: Telford, Shropshire

Re: Headstock bearings

Post by Bluehazebrakes »

I bought mine from pyramid parts from ebay had 2 sets that did not fit right, in the end i took my lower head stock to a local machine shop and the chap showed me where the original tool had sheared whilst turning the stem, he turned it a little and all went together fine. have a look for tell tale scores of a tool bit failing in prodution.
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mizzytheman
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Joined: Tue Dec 28, 2010 1:17 pm
Location: Knowsley, Liverpool

Re: Headstock bearings

Post by mizzytheman »

Hi Phil,
Thanks for that. Got mine from pyramid as well but broke the second bottom bearing trying to get it off because the seals they supplied did not fit properly. Not knocking them as they did supply a second set and the seals for free. But was a bit weary about buying another set untill I got some sound advice. Think I'll take the lower headstock down to the local engineering shop and get the mod done as per sketch.

Kind Regards

Martin
philjobooboo wrote:I bought mine from pyramid parts from ebay had 2 sets that did not fit right, in the end i took my lower head stock to a local machine shop and the chap showed me where the original tool had sheared whilst turning the stem, he turned it a little and all went together fine. have a look for tell tale scores of a tool bit failing in prodution.
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yeadon_m
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Joined: Sat Jan 02, 2010 7:10 am
Location: Canterbury Kent

Re: Headstock bearings

Post by yeadon_m »

Martin,

It may be obvious in which case ignore. If not, this advice I got and used is really worthwhile.

To get the lower bearing off the stem, heat it with a blowtorch and blow instant pipe freeze up the stem. The contraction/shrinkage makes it easier to get it free.

Make the small mod to the stem to allow the top bearing to go on fully as previously discussed.

Putting the new lower bearing on: stick the whole steering stem in the freezer overnight. Warm the bearing on low heat in the oven. Grease it all up and tap it oto the stem using a drift (I used a long piece of thick-walled plumbing pipe) and it slipped on without any heavy duty hammering!

Similarly, putting the outer races into the headstock, freeze them first and warm up the headstock with a hot gun (care of your new paint!). Try not to hit thumb with hammer (my black nail took 4months to grow out :-(((

Good luck!
Mike
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mizzytheman
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Joined: Tue Dec 28, 2010 1:17 pm
Location: Knowsley, Liverpool

Re: Headstock bearings

Post by mizzytheman »

Thanks Mike,
To be honest it wasn't obvious, being a heating engineer I tend to use big hammers, chisels etc, always tend to use the blow lamp when things get stubborn but never thought of the pipe freeze. Thanks for the advice.
Regards
Martin
yeadon_m wrote:Martin,

It may be obvious in which case ignore. If not, this advice I got and used is really worthwhile.

To get the lower bearing off the stem, heat it with a blowtorch and blow instant pipe freeze up the stem. The contraction/shrinkage makes it easier to get it free.

Make the small mod to the stem to allow the top bearing to go on fully as previously discussed.

Putting the new lower bearing on: stick the whole steering stem in the freezer overnight. Warm the bearing on low heat in the oven. Grease it all up and tap it oto the stem using a drift (I used a long piece of thick-walled plumbing pipe) and it slipped on without any heavy duty hammering!

Similarly, putting the outer races into the headstock, freeze them first and warm up the headstock with a hot gun (care of your new paint!). Try not to hit thumb with hammer (my black nail took 4months to grow out :-(((

Good luck!
Mike
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camper

Re: Headstock bearings

Post by camper »

hi

just curious about fitting seals with these tapper bearings,when i brought my bearings i did not have seals where could i get the seals from as it dont show oin the books.
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