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Hi,

It is with great sadness and disbelief that I report the failure of another timing side bearing, this failure on my friends Goldie last week with less than 3k on the clock since rebuild.


Mikeb.



Last edited by 68triton; 09/11/14 7:26 pm.

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And you are surprized.. Sory that a 60 year old obsolete bearing may no longer be available. OK, so for those that are not aware, those type of roller bearings are inch type.. both side rollers are that way on the Goldie, not so on the non-Goldie drive side bearing. And I heard they are out of production by the quality makers, the volume is too low and they are expensive. So, if this is correct, then once they are gone.. well.. good luck. I know that the supply "stash" here is out of them. I will ask if there are any more good ones to be had.. It is likely that some of the low volume Vendors may have a few left.. bet the prices go up. I know some of the Norton bearings are getting scarce too.

Ron

Last edited by Ron - in California; 04/20/14 3:59 pm.
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Mike, sorry to hear this. I wish I went with metric bearings on my Pearson crank.

I recently found post about counterfeit bearings on the SKF website: http://www.skf.com/group/our-company/business-care/anti-counterfeiting/index.html


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Mike.. if you find some good bearings.. then you will be all set... I only hope that sometime down the road all the Brit Bike Vendor guys get together and get some proper ones made.. But I doubt it.. those bearings are pricey.

Yes the non-Goldies use the same T/S bearing.. but the cheap ones may live on a low power low rpm engine.. dunno...

Good Luck..!

Ron

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The bearing availability issue is a real serious one, to state the bleeding obvious. Somewhat in the defense of the rebuilder I read an article that the main problem with these bearings is crystallization within the metallurgical structure which only shows up under certain load conditions, and is unrelated to dimensional tolerances of the finished product. IE it's just a matter of luck whether you get good metallurgy in the bearings or not when the tolerances are to spec. Chinese engineers are working on this issue and the quality of the metallurgy with some manufacturers has greatly improved in the past couple of years with far fewer bearing failures. But in one sense almost all bearings are 'counterfeit' now as most all major brands including Hoffman Pollard and many others have UK holding companies but the products are made in India or China. I won't get into the politics of how this bearing situation has arisen but it is quite interesting and relates to many other systemic problems in the industry. By the way another company called Locate ball bearings will try to find original bearings for you, but they are hit-or-miss and I won't say more than that... smile

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Quote
main problem with these bearings is crystallization within the metallurgical structure which only shows up under certain load conditions, and is unrelated to dimensional tolerances of the finished product.


Manganese inclusions, I used to buy Steel for major Shell bearing manufacture where the same problem results in a different issue when the shell half circle is formed. You can specify an acceptable level of Manganese Inclusions, get all the certificates under the sun saying the blast melt was tested and the low level required for bearings was found. But in the end its a single sample from a 25T melt that goes into the slabs that are then rolled. Your sample may be good but its a crapshoot if the slab your bearings end up coming from have a bad 30kg section with a high inclusion level you are stuffed. Only way to reduce the problem was to select a specific steel mill you trusted and insisted on only using them and audited their tests annually to see the average levels were low.

I bought 30K Tonnes of bearing steel a year and could not get it 100% even being able to say only use that mill, what chance has a small low volume outfit got buying from a stockist and insisting it must come from a specific Belgium Mill.

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Anyone tried a ball bearing instead? Most other singles use them on the timing side don't they?

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A ball bearing is great in some places.. but put one on the timing side, and you risk it may possibly ruin your cases. You see the crank needs to have one spot to locate it.. this is the drive side ball bearing.. and as the cases grow when hot and the crank is a flexy flier, it needs to float on the opposite side. I found a used engine where this was done and the case was well worn on the timing side, as the bearing was spinning and moving. Also keep in mind that the roller has more load rating than a ball. Not sure the load is an issue or not.. But it could be.

Now the early low power singles had both as roller and a ball on the timing side.. never heard of an issue, but those are much lower revving engines. I always thought that would of been even better with a second roller, but in the end seems it is not needed.

Now I have seen modern big singles with ball bearings on both sides, but they use much larger bearings and the housing bores often are either pinned or cast in steel. But modern bikes also have narrower and small O.D. cranks. Not sure how that comes in to play.. but worth mentioning.

Nice thinking though...

Ron

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David Holder has regularly been having production runs of RHP inch bearings, with specific specifications for various models of British motorcycles, made in the U.K. His most recent effort is the Triumph 4 speed high gear bearing (57-0448) which is used in many other applications. After a short period where he was getting another UK bearing made for this application, he stepped up and had RHP do the job.

As recently as last year he was supplying the RHP bearing for the Gold Star bearing in question. I only ran out of our supplies a few months ago. I suspect I will see more in due time. The RHP offerings are not cheap which drives a lot of dealers, and engine builders, to look for cheaper alternatives. It has been my opinion that this is short sighted and continue to support David by holding large stocks of RHP bearings.


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