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main bearing issues
#435089 05/15/12 3:25 am
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I couldn't find it in the search or looking at a couple of pages in the Norton section.
Is there a serial # when the commando main bearing issues were resolved? Is it just combat motors or all commandos? Thanks gents.

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Re: main bearing issues
Shades34 #435102 05/15/12 9:26 am
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It was just Combat motors.
But be careful, check carefully that what you are offered is actually the specified heavier duty bearings....

Re: main bearing issues
Shades34 #435103 05/15/12 9:35 am
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Originally Posted by Shades34
Is there a serial # when the commando main bearing issues were resolved? Is it just combat motors or all commandos?


According to the Norton Service release information, the Combat specification was discontinued from serial 211110, and the R&M/RHP 6/MRJA30 "Superblend" bearings were fitted from 211891 around August 1972. During early 1973 the 6/MRJA30 was superseded by the FAG NJ306E bearing, part 064118 (FAG NJ306E.M1 C3).

Re: main bearing issues
Shades34 #435125 05/15/12 1:26 pm
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Thanks guys, L.A.B., thanks for the great info. I knew I was in the right place. Now I have to get home and check my #s!!

Re: main bearing issues
Shades34 #435142 05/15/12 2:51 pm
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Originally Posted by Shades34
Now I have to get home and check my #s!!


Even if it is earlier than 211891 the original bearings could have already been replaced with the FAG bearings-unless you know your Commando's history way back?

Re: main bearing issues
Shades34 #435182 05/15/12 9:06 pm
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The FAG's were just one of many similar spec bearings ?
And are no longer available, for quite some time now ?
Even the factory used different brand bearings ??

Re: main bearing issues
Rohan #435186 05/15/12 9:53 pm
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Originally Posted by Rohan
The FAG's were just one of many similar spec bearings ? And are no longer available, for quite some time now ?


??

If you were to order genuine 064118 main bearings from just about any decent Commando parts supplier then you should get FAG NJ306E.M1 C3 brass cage bearings.

Re: main bearing issues
Shades34 #435263 05/16/12 10:29 am
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Re: main bearing issues
Rohan #435275 05/16/12 11:57 am
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Originally Posted by Rohan
FAG's, freshly made in China ???


Yeah....so what?

http://www.fag.com/content.fag.de/e...iew_images=true&continent_id=37&

Re: main bearing issues
L.A.B. #435304 05/16/12 3:40 pm
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Good point. I just picked up a pair of 73s. One 750 and one 850 and don't know what I am going to do with them. One has a siezed motor with 7k on it and the other was chopped but the motor is loose. I think they are both later but haven't checked it yet.

Re: main bearing issues
Shades34 #435305 05/16/12 4:00 pm
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All 850's were supposed to have had the extra high load capacity (FAG-as far as I'm aware) main bearings.

One thing you should seriously think about replacing in either gearbox is the layshaft drive-side ball bearing. This bearing really should be replaced with a roller bearing which is now supplied as the standard replacement part (or there is also a high grade 6203TB ball bearing option as recommended by at least one Norton specialist)

http://www.doov.com/apps/nortoncomp...pgrade&catid=1:upgrades&Itemid=8

Last edited by L.A.B.; 05/16/12 4:14 pm.
Re: main bearing issues
L.A.B. #435602 05/18/12 8:32 am
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Originally Posted by L.A.B.
Originally Posted by Rohan
FAG's, freshly made in China ???


Yeah....so what?



So what ?
At a manufactured cost of about 55 cents per piece (each)...

Re: main bearing issues
Rohan #435605 05/18/12 9:09 am
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Originally Posted by Rohan
At a manufactured cost of about 55 cents per piece (each)...


...As much as that!!! shocked laughing

Re: main bearing issues
Shades34 #435632 05/18/12 12:45 pm
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Chinese bearings are actually well made dimensionally, as long as FAG is importing the steel into China then the quality will be equal to those made outside of China. The main reason for early failure of Chinese bearings is inclusions, small nodules of carbon and other crud in the steel which are weak spots and with the constant loading and unloading as the balls and rollers move over the steel creates wear spots. As their Steel industry progresses the level and size of inclusions will drop and by now some of the better steel makers will be at international stds for inclusions, once more of them are then they will last as long as non Chinese bearings.

Re: main bearing issues
Shades34 #437133 05/28/12 8:17 pm
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I just ordered and received new mains from OldBrits and this is what i got. I think Fag is still in business and in Germany
Old
[Linked Image]
New
[Linked Image]


75' 850 Commando
67' Bonnie (on the lift being restored)
Honda CB160, CB350, SL100
BMW K1200LT
KTM 450 & 950 Adventure
Re: main bearing issues
dmat #437199 05/29/12 7:55 am
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The 1970 750 I had , the std ball races had gone at 7.000 miles .

Probably a lot related to use / abuse , and how well assembled .
End float , clearance etc .

Generally Anglophiles are prepared to buy german bearings , but prefer swedeish . Not a area where skimping on cost pays dividends, theyre a bit hard to get to , if theyr off .

Re: main bearing issues
Shades34 #443420 07/06/12 8:10 am
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Originally Posted by Shades34
I couldn't find it in the search or looking at a couple of pages in the Norton section.
Is there a serial # when the commando main bearing issues were resolved? Is it just combat motors or all commandos? Thanks gents.

This issue is complicated by a few things. First of all the Norton vehicle information plate shows the calendar year of production and in North America we register the machines by model year which is often different. There seems to be difficulty in discovering the model year from factory records.

The main bearing problems were primarily with a single engine the high-compression Combat which was produced mainly, or only, during the 1972 calendar year. Early in the year Norton switched over to producing all high-compression engines. The bearings that were used in these high-performance engines failed prematurely. The engine produced too much torque for the load rating of the standard bearing even at low engine speeds. Norton halted production and then sent the engines off for correction. Part of the fix was to fit a special 6/MRJA30 bearing made by Ransome & Marles. After correction the engines were then installed in bikes and sold.

During the same year Norton reduced compression on their other engines to 8.5:1 to meet NOx emissions requirements like everybody else. These low-compression engines did not produce sufficent torque to require the special bearing and normal, cheaper bearings were then fitted.

A representative of R&M has told me that the FAG bearing is the equivalent of a normal MRJA30 but not of the special 6/MRJA30. He also told me that they still have stock of this special "6/" bearing for the high-compression motor.

Unless your Commando engine is a high-compression one the special bearing is not needed and the FAG will do. If you fit the NJ306 to a high-compression Combat engine, however, you can expect early bearing failure.

Re: main bearing issues
Shades34 #443481 07/06/12 5:56 pm
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The E on the end of the number on modern roller bearings signifies the high capacity bearing equal to the 'Superblend' made by R&M . EG NJ306E

Re: main bearing issues
kommando #443499 07/06/12 8:15 pm
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Originally Posted by kommando
The E on the end of the number on modern roller bearings signifies the high capacity bearing equal to the 'Superblend' made by R&M . EG NJ306E


Well I'm no bearing expert but I expect the folks at R&M are. Here is what they wrote to me a few days ago:

"...R&M 6/MRJA30 is a "Special Bearing".

The number 6, before the letters, denotes that it is the 6th variation of a "standard" MRJA30.

Whereas FAG would make an equivalent to the "Standard" MRJA30 it is highly unlikely that they would have made an equivalent to the 6/MRJA30.

Given the scarcity, and therefore the cost, of a genuine 6/MRJA30 I think people have probably put forward the more common FAG equivalent and ignored the differences,,,"

They went on to add, "...we do show some stock of the 6/MRJA30 bearings."

None of this applies to me because my Commando is a low-compression 850 but I would still hate to see someone with the very rare Combat engine damage it by using the incorrect part.

I'm curious to know why a moderator has taken such a keen interest in what R&M has to say about bearings? Their comments only apply to a bearing made for the high-compresson Combat engine and those have got to be pretty scarce these days.

Re: main bearing issues
Murray_B #443503 07/06/12 8:42 pm
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Originally Posted by Murray_B
The main bearing problems were primarily with a single engine the high-compression Combat which was produced mainly, or only, during the 1972 calendar year.


In fact, premature failure of the main bearings had been a problem even before the introduction of the Combat engined models, as the bearings were first upgraded around October 1971.

Originally Posted by Murray_B
Early in the year Norton switched over to producing all high-compression engines.


Not "all", as Commandos with standard spec. engines were still produced during the Combat period.



Originally Posted by Murray_B
During the same year Norton reduced compression on their other engines to 8.5:1 to meet NOx emissions requirements like everybody else. These low-compression engines did not produce sufficent torque to require the special bearing and normal, cheaper bearings were then fitted.



After Combat production ceased (around August 1972) two "standard" engine versions became available for late '72 and for '73, with different 32mm carb. cylinder heads giving "High compression" (up to 9.6:1 CR depending on gasket arrangement) or "Low compression" (up to 9.2:1 CR dependant on gaskets) but without the Combat camshaft therefore the compression ratio was not significantly reduced and it would have been neither sensible nor logical to fit lower spec. bearings to any post-211891 750 engine, and after the serious lesson they'd learnt-it seems highly unlikely that the factory would have been foolhardy enough to do such a thing.



Originally Posted by Murray_B
A representative of R&M has told me that the FAG bearing is the equivalent of a normal MRJA30 but not of the special 6/MRJA30.

Unless your Commando engine is a high-compression one the special bearing is not needed and the FAG will do.


??

The standard replacement bearing for all models from early 1973 (Service Release N2/10) was the "extra high capacity" (FAG) bearing, "A new main bearing capable of carrying a much higher load than any offered before, has been introduced." and; "the new bearing, part number 064118[FAG] supersedes the old type 063906[6/MRJA30]...."

The 064118 FAG306E still being the standard replacement main bearing supplied by Andover Norton today.


Originally Posted by Murray_B
Well I'm no bearing expert but I expect the folks at R&M are. Here is what they wrote to me a few days ago:



The original R&M (Ransome & Marles) ceased to exist after 1969 when the company merged with Hoffman and Pollard!

http://en.wikipedia.org/wiki/Chelmsford

"The firm [Hoffman] became Ransome Hoffmann and Pollard (RHP) after an amalgamation with the Ransome and Marles Bearing Company together with the Pollard Ball and Roller Bearing Company in 1969. The factory that once employed 7500 employees over 50 acres in its heyday was wound down during the 1980s and finally closing for good on 23 December 1989.

The company assets and name were absorbed into the Japanese NSK Ltd bearing company in early 1990 trading as NSK-RHP Ltd. at its UK base in Newark on Trent with the historic R.H.P name finally disappearing in 2001."


It would seem the name "Ransome & Marles" is actually being used by: "The Orinoco Bearing Co." of Leeds, which appears to be a shed on a Leeds trading estate!

http://www.ransomeandmarles.co.uk/
+44 (0)113 263 1919.

http://www.orinocobearings.co.uk/contact.html
+44(0)113 263 1919


The name 'Ransome & Marles Bearing Co. Ltd.' is still retained by NSK, R&M as a company having been dormant for some time.
http://companycheck.co.uk/company/02270163



Last edited by L.A.B.; 07/07/12 11:58 am.
Re: main bearing issues
Shades34 #443683 07/08/12 8:31 am
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This is a common problem with manufacturing companies today which is the difference between Brands and Physical assets. So we currently have:

The Hepolite Brand being owned by Wassells selling Cycle Craft pistons fitted with Hastings rings in Hepolite boxes. The reputation in the brand was developed by the orginal Hepworth and Grandage factory, which became part of AE then part of T&N which was then bought by Federal Mogul. They closed all of the old factories and then sold off the brands. Other than a piece of paper showing ownership the Hepolite brand now has no connection with any of the orginal assets or personel of the orginal factory.

You can repeat this exercise with many other brands as manufacturing has left the UK and gone elsewhere.

Its all lawful but means buying on the reputation of old brands is fraught with danger. It costs money to buy these old brands and you have to charge for this to make a return, so you have to have a story to back this higher price, the story is marketing.

Re: main bearing issues
Shades34 #443723 07/08/12 3:49 pm
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L.A.B NSK still markets bearings under the RHP label. Packed in the distinctive blue RHP box, thhe largest supplier of these inch series bearings seems to be David Holder, Velocette Motorcycle Company.


Re: main bearing issues
John Healy #443735 07/08/12 4:59 pm
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Originally Posted by John Healy
L.A.B NSK still markets bearings under the RHP label.


Yes indeed. No problem there (RHP).
http://www.ahrinternational.com/rhp_bearings.htm


Re: main bearing issues
kommando #444018 07/10/12 2:39 pm
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Originally Posted by kommando

You can repeat this exercise with many other brands as manufacturing has left the UK and gone elsewhere.



AMAL's another good example. Nothing to do with the Original OEM AMAL Company, or the Spanish OEM manufacturer. Just buy the trademarks, manufacturer the components in China, put them in a box in England, and wear a nice 'Genuine AMAL' T-shirt to fool the masses!

Re: main bearing issues
TripleTown #444042 07/10/12 6:29 pm
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Originally Posted by John Healy
L.A.B NSK still markets bearings under the RHP label. Packed in the distinctive blue RHP box, thhe largest supplier of these inch series bearings seems to be David Holder, Velocette Motorcycle Company.


Well, John Healy, the root of the bearing confusion seems to be about the meaning of the word "supercede".

Back in 1970 it was possible to order a 350 c.i.d. high-compression crate motor from General Motors that was capable of producing 300 b.h.p. By 1975 the only 350 still available was a low-compresson one that was rated at 145 h.p. (160 by the old rating). The low-compression engine "superceded" the high-compression one but few observers would think the newer engine was superior or even equal to the old one by most measures.

The word "Superblend" is often thrown out in conversation but it is diffucult to discover what the term actually means. Is it a trademark and If so then which company was it registered to?

We do know for certain from S.R. N2/9 that a R&M 6/MRJA30 is a "Superblend" bearing. Apparently, a later S.R. indicates the more common NJ306E "supercedes" the 6/MRJA30 but I have not seen this S.R. That does not mean, however, that any of the NJ306E bearings can be correctly called a "Superblend" without knowing exactly what "Superblend" refers to.

At least a half-dozen companies manufacture direct replacements for a FAG NJ306E Type 2 roller bearing and there are even a couple of other types that can be subsituted. The RHP 6306-Z dual-row ball bearing comes to mind. The NJ306E seems to be a fairly common part but I can discover nothing to suggest that the R&M 6/MRJA30 was used for anything other than the main bearings of high-compression Norton engines. It seems to have been made for that singular purpose.

There is no doubt that many other parts can be subsituted for the 6/MRJA30 Superblend main bearings in a Combat motor but will the substitute last as long? That is the important question.

Last edited by Murray_B; 07/10/12 8:12 pm.
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