Taper roller head bearing conversion

Was looking for a bearing for my 68. Have seen the one supplied by most parts supplier is metric p/n 30205
Which is 25x52x16.25mm. This is 1.25mm thicker than standard and when 2 are fitted, 1 on top and 1 on the bottom it means the top and bottom yokes are 2.5mm further apart. This means the shrouds won't fit properly.

My question is... I have found a taper roller bearing that is imperial. It is 25x51.994x15.011. P/n is timken 7097 cup and 7204 cone.

Has anyone used this bearing and if so any issues.

Thanks
D

Why not fit the later bearing set up. Although the bearings were never designed to be used as a headstock bearing, they work perfectly & are a fit & forget set up. I have them in my '68 & they are fine. All you need is 6205 2RS (x2) & the correct length of spacer tube. These bearings are 52x25x15mm.
Martyn.

I am pretty sure the 1968 triple trees don't require a spacer tube, regardless of the type of bearing you install. Even if you are changing from ball and race to sealed bearing or tapered roller. You adjust the preload on the newer bearings in the same manner you would if it were the original ball and race. 1971 and up you need the spacer.

Stephen Hill

Dean said:

Was looking for a bearing for my 68.

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Get a 7205-2RS. Direct replacement.

And on the old yokes you do not need a spacer tube. Bearing pre-load is done with the adjuster nut and then everyting is clamped by the upper yoke and the top nut.


Tim

Why not fit the later bearing set up. Although the bearings were never designed to be used as a headstock bearing, they work perfectly & are a fit & forget set up. I have them in my '68 & they are fine. All you need is 6205 2RS (x2) & the correct length of spacer tube.

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My bike came with tapers but I could never get them nicely adjusted, very little torque required on the lower nut. In truth they were worn out with lightly pitted tracks. I replaced as above and the steering is much improved at low speed especially.

Whilst it is true a spacer tube is not required with the earlier yokes, by using one, the nuts can be tightened down & never touched again. The problem with the adjustable set up is, when the top nut is tightened up, the bearings will also tighten a fraction. This is down to the clearance in the threads, however slight. Later BMW airheads & K bikes fitted with Showa forks addressed this by use of a different lock nut/adjuster system.
Yer pays yer money & takes yer choice! It works fine for me.

Keith1069 said:

Why not fit the later bearing set up. Although the bearings were never designed to be used as a headstock bearing, they work perfectly & are a fit & forget set up. I have them in my '68 & they are fine. All you need is 6205 2RS (x2) & the correct length of spacer tube.

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My bike came with tapers but I could never get them nicely adjusted, very little torque required on the lower nut. In truth they were worn out with lightly pitted tracks. I replaced as above and the steering is much improved at low speed especially.

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Maybe it was that they all wear out in the straight ahead position, my trick to lengthen the bearing life, knock out each bearing cup in the headstock and turn it about 120 degrees clockwise, ( looking at the faces )in opposite directions and reassemble with thick grease. 8)

I have annular thrust bearings in mine, that may be what the -2RS is?. They're not especially cheap like the standard bearings, but not outrageous if you can get them reasonably, I saw some on ebay a long time ago.

I never knew the early bikes didn't need the spacer, I was always worried about that. But yeah, the tree goes in from the bottom, didn't think about that.

Dave
69S

Hi all

Thanks for the info. The reason I am looking at 7097 cup and cone is because it is a taper roller and IMO this is going to perform better in this situation. Taper rollers are designed for radial and axial loads where ball bearings are only for radial loads.

As I have the early triple trees with the fine thread and lock nut it should be easy to set up.

Are the angular contact bearings designed for axial loads? And how much clearance do they have?
A taper roller clearance can be adjusted depending on how tight it is set where a ball race is set at manufacture.

With a correctly set up taper roller you have virtually zero play. Sure it's not a sealed bearing but I don't mind dropping it out once a year when I do a yearly maintain check. And also you can check condition.

I am also probably a bit bias toward a roller set up as this is what all my previous bikes have had. Either as standard or retrofit.

I think I will give it a go and let you know.

Thanks all,
D

2RS is just a fully sealed bearing with a Rubber Seal each side.
I kind of like the idea of a taper lower and ball upper, most big European bikes of that era has taper roller steering head bearings.
At least it is a step up from cup and balls rolling all over the show.

Fitted taper rollers to my 68. Worked a treat it compressed the rubbers at the top of the headlight ears about 3/32" so they are nice and tight. With the 7205-2RS bearings the ears were loose due to them being thicker than the original race and loose balls (happy to get rid of that setup) Only issue is as 7097/7204 cup and cone are an odd size they were a bit pricey.

Just a thought but is the average owner capable of correctly adjusting the pre-load for an angular contact ball race or taper roller bearing? Wonder what comments one would receive on the subject from a bearing manufacturers Applications Engineer?? The comments I once heard from a Renold Gentleman about motor cycle chain users was interesting as were those i heard froma belt industry Gentleman......!
Taper rollers were a go faster must have modification in the late 60s when I was blasting around with brain totally disengaged on my Dommy and with the help of the gods / Manx fairies etc I survived still in one lump and NOT in a wheelchair etc like so many. I found the inner cone of 30205s stuck out top and bottom causing a sealing problem. A thick lump of felt solved the bottom problem but it required a BSA wheel hub cover with its much deeper lip to solve the top one. An Army B40 one I believe..not perfect but oit did the job. A couple of years later they were notched and had to be replaced. Not a suprise really as the rollers probably never move with respect to the raceways 90 % plus of the time and cup and cup ball steering head bearings would notch the same over time.
I note that the 7205 angular contact ball race bearing is said to now be available fully sealed...they were not in my young days. (Wonder if the 7205 B 40 degree angular contact version is? But that is pure curiousity).
Personally I hear that the sealed 6205 2RS ball race bearings work well in Commando steering heads and are so cheap these days if you buy foreign bearings that is but I understand there are different grades of Chinese manufactured bearings..... I suspect the sleeve seperating the bearing inner raceways was included to stop the mechanically incompetent from over tightening the bearings and suspect it is why these bearings work so well !
Looking on the web at the Heller Bearing drawing of the 7097/7204 taper roller bearing combination I note that on one of the drawings shown the inner raceway is lower than the outer raceway thus if this is the case and the outer raceways top and bottom are fully home in their steering head housings then the spacer between them will require shortening to suit. Not that I had a spacer tube between my 30205s on my Dommy mind you but that could be why they notched so quickly!!
6205 2RS sealed for life bearings work well, are easily fitted and are I suspect far less expensive than taper rollers.......

Different grades of Chinese bearings - most probably the sample you get sent for approval is from a state of the art Western managed factory - place the order then you get the crap! it's common practice with parts, but sadly some of the crap parts are now better than produced in the UK, they're learning fast!

I have Timkens in mine, forget the number, it's been so long. They're due for an adjustment.

As Matchless writes:

All you need is 6205 2RS (x2) & the correct length of spacer tube.

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If you fit these bearings you will need the spacer tube or they will fail. Would you fit wheel bearings without a spacer tube? This system is the biz and truly is fit and forget.

I am sure all 850's came out of the factory like that, and my own high mileage Mk3 appears to have the original set.

Dave

All you need is 6205 2RS (x2) & the correct length of spacer tube.

I will second that too many folks looking for a solution to a problem that does not exist

Look in to the head stock of a current Japanese super bike Angular contact bearings not tapers

My low mileage MKIII has the originals and they're perfectly smooth and tight. Should I detect and play or roughness I'll replace them with like kind.