Super blend help

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I have a 74 850 and my friend has a 73 750, I have examined the main bearings on both engines, and notice the following differences.

850, has FAG bearings with the inner sleeve only of the bearing reamaing on the crank shaft. The outer case, rollers & cage remain in the crank case.

750, the sleeve together with the rollers & cage remain on the crank shaft, with just the outer case in the crankcase.

We believe these low milage bikes have not had their crankcases parted before.
So how come the diferent styles of roller bearings, both sides are roller?

Can anyone add some wisdom?

Regards Richard
 

L.A.B.

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Are there any markings on the 750 bearings?

The 'Superblend' type bearing was supposedly fitted from engine number 211891-on (Aug. 1972).

The early Superblend bearings fitted to Commandos were originally British-made R&M/RHP (Ransome & Marles, Ransome-Hoffman-Pollard) type, and should be marked: '6 MRJA30'.


The FAG type is reported to have a higher load capacity than the RHP type and these were fitted from early 1973.

The RHP roller cage stays with the inner race.
 

ILLF8ED

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Main bearings

Richard,

Your 850 has "superblend" bearings (FAG NJ306E) and the 750 has the older 6MJRA30 type. The FAG bearing was Norton's answer to rapid main bearing failure on the '72 combat 750 engines. From the late '72 model year onward Norton used the FAG bearings. A '73 750 originally would have come with superblends, so someone has replaced them.

Only the FAG bearings were known as superblend. They have a larger radius at the ends of the rollers allowing for more crankshaft flex without digging into the bearing races, which was the failure mechanism previously.
 

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Re: Main bearings

illf8ed said:
Only the FAG bearings were known as superblend. They have a larger radius at the ends of the rollers allowing for more crankshaft flex without digging into the bearing races, which was the failure mechanism previously.


Norton Service Release No. N.2/9 AUGUST 1972 Says the following:

"In order to extend main bearing life, a change of roller main bearing specification has now been authorized, and fitted on production engines from engine number 211891.

The new roller bearing is designated "Superblend" with an increased load carrying capacity and are supplied under part number 063906 (manufacturers part number R & M* 6/MRJA30)."

* R & M (Ransome & Marles) later becoming RHP.
 

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main bearing

L.A.B.

You are correct RHP 6/MRJA30 was the earliest used "superblend", my appology. Locally the only superblend supplied and used is the FAG NJ306E which has the same specification and was used by Norton on the 850s, p/n 064118. For the original question, the answer is the same. The 750 in question has a non-superblend main bearing if the caged rollers remain on the crankshaft.
 

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Re: main bearing

illf8ed said:
The 750 in question has a non-superblend main bearing if the caged rollers remain on the crankshaft.

That may not be totally correct: http://home.clara.net/captain.norton/cn ... tml#2.23.1

Quote: "Hudson also mentions that the earliest Superblends were marked differently. They were by R&M (now RHP) and were numbered 6MRJA30, the "6" having been added by hand to the stamped number to signify it was a Superblend. Also, some or all of these bearings have the rollers fastened on the inner race rather than the outer."

Also in the NOC John Hudson engine strip/rebuild video as John splits a 750 crankcase, the cage stays with the inner race and he identifies the bearing as an "....early Superblend bearing by RHP.......6MRJA30....."

If the bearings were the pre-Superblend type wouldn't the timing side be a ball and not a roller?

Hopefully RichardS can identify the bearings from the markings?


-----------------------------------------------

Additional info 'NJ' coded bearings have the cage assembled to the outer race, those with the cage assembled on the inner race are 'NF' type
 
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Re: main bearing

L.A.B. said:
If the bearings were the pre-Superblend type wouldn't the timing side be a ball and not a roller?

Not necessarily. A DPO could have rebuilt it with a pair of non-superblend roller bearings either to save some money or because he was too ignorant to know the difference.

Also I thought I read somewhere that Norton fitted non-superblend roller bearings to each side for a while. IIRC that was on the early Combat engines.

Most of these engines have probably been rebuilt at least once in the past 30 years so there's no telling what you might find in there.

Debby
 

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RichardS said:
We believe these low milage bikes have not had their crankcases parted before.

Debby,

You are right about the two roller bearings fitted from Eng. No. 200001 (1972 models).
 
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Just to add a bit extra I checked my service notes from the 70's

ref from John Hudson and Tim Stevens

recomended bearings by above
both are super blends ( there words)
one from Ransome and Marles Norton number 063906 and one from F.A.G. Norton number 064118
either should be used in 500 to 750 engines and the factory recomended only F.A.G. in the 850's
They also mentioned float between 10 and 30 thou. but not to worry if not as long as there was some float.
outer ring of bearings were locked in useing Loctite bearing fit. (special note if using bearing fit ensure they are fully home before before glue sets.
they also made special note of the following numbers.
Use bearings with following markings
NJ306E ( the E must be present as bearing without it are to weak)
OR 6 MRJA30 on this bearing you may find the 6 hand engraved so only use a known quality supplier ( some may add the 6 themselves.)
They also noted that the timing side fit may not be very tight on the crank,
tyey also made note of the following number for a much harder bearing NJ306E M1 but never stated if it was recomended.

back in the early 80's I remeber a discusion I had with John Hudson about bearings from my Commando SS as to what was original fit, what he did say was that Norton would often use what they could get from either supplier.
I hope this helps.
 
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I don't recall who wrote this but I saved it because it sounded like the truth. The 6mm center gives a good idea of how reduced in load the Super Blend became. norbsa
WAS LOOKING AT OLD POSTS AND SAW ONE ON THIS SUBJECT.
A FEW FACTS.
THE ORIGINAL COMMANDO USED THE SAME BALL AND ROLLER RACE BEARINGS AS THE ATLAS /650 MOTORS. THE ROLLER WAS A SKF 8MRJA30. NOTE THE 8. THIS DENOTED A BRASS CAGE. THE 11 ROLLER ELEMENTS WERE APPROX 11.12MM O.D. AND 11.12MM WIDE WITH A SLIGHT RADIUS ON THE ENDS LEAVING A PARALLEL WIDTH OF 10 MM. THE DYNAMIC LOAD CAPACITY WAS 41,000N AND THE STATIC WAS 35000N.
CRANKSHAFTS BROKE( THANKS TO TRHE STRESS RAISERS NORTONS INTRODUCED INTO THE CRANKS...PLUS OF COURSE THE HIGHER CRS AND OWNERS SCREWING THE BALLS OUT OF THE MOTORS) AND THE MAINS COULD USUALLY BE HEARD RUMBLING AT ABOUT 4000 MILES. THE CRANK FLEX WAS CAUSING THE EDGES OF THE ROLLERS TO DIG INTO THE INNER AND OUTER RACEWAYS, STARTING THE QUICK ROAD TO DESTRUCTION.. VARIOUS PEOPLE WERE CONSULTED AND BARRAL SHAPED ROLLER BEARINGS WERE DRAWN UP ON THE BACKS OF FAG PACKETS. THE END RESULT WAS THAT SKF MADE A FEW SUCH BEARINGS BUT THEY HAD STEEL CAGES AND NORTONS ENDED UP ADOPTING A RAMSOM AND MARLES BEAING DESIGNATED 6MRJA30. NOTE THE 6. THIS DENOTED A SPECIAL, IN THIS CASE BRASS CAGE AND 13 SPECIAL SHAPED ROLLING ELEMENTS. THE ROLLING ELEMENTS WERE APPROX 9.53MM WIDE AND 9.53MM OD. THERE WAS STILL A RADIUS ON THE OUTER EDGES BUT THE PARALLEL SECTION OF THE ROLLERS WAS ONLY APPROX 6MM (9.53MM DIA) WHICH THEN BARRAL SHAPED DOWN TO APPRODX 9.46MM AT THE POINT THE RADIUS STARTED. BOTH THE DYNAMIC AND STATIC LOADS WERE LOWER THAN THOSE OF THE OLDER BEARING AT, DYNAMIC 35,500N AND STATIC 31,000N.
NOW OF THE SKF BEARING I FOUND, EX NORTON STOCK, ONE WAS MARKED NJ306 (1972)AND THE OTHER NJ306E (1972). THE NJ306 HAD 11 ROILLERS OF APPROX 10MM WIDTH AND DIA BUT HAD A PARALLEL SECTION OF APPROX 7MM FROM WHICH IT TAPERED TO APPROX 9.97MM BY THE START OF THE RADIUS ON THE ENDS. THE LOAD CAPACITIES WERE GIVEN TO ME BY SKF AS DYNAMIC 36900N AND STATIC 20000N. THE NJ306E BEARING HAD 12 ROLLERS APPROX 12MM WIDE AND 11MM OD WITH A CENTERPARALLEL SECTION OF APPROX 8MM AND THEN TAPERING DOWN TO APPROX 9.97MM BY THE START OF THE RADIUS AT THE ENDS.ITS LOAD VALUES WERE GIVEN TO ME AS DYNAMIC 51200N AND STATIC 30000N.
SO THE ORIGINAL AND ONLY SUPERBLEND BEARING EVER USED IN PRODUCTION BY NORTONS WAS THE 6MRJA30 WHICH WORKED WONDERFULLY WELL EVEN THOUGH IT HAD LOWER DYNAMIC AND STATIC LOAD VALUES THAN THE OLDE BEARING THAT GAVE THE ORIGINAL PROBLEMS.
IN THE DAYS WHEN THE OLDE 8MRJA30 BEARING WAS PRODUCED WITH ITS BOG PARALLEL ROLLING ELEMENT AS FAR AS I AM AWARE, NOT HAVING RESEARCHED IT, ALL MANUFACTURS ROLLERS WERE SIMILAR. IF YOU BUY ANY MANUFACTURERS BEARING NOW I SUSPECT YOU WILL FIND THEY ALL HAVE A VERY SLIGHT BARRAL SHAPE TO THE ROLLERS BUT IT IS NOT AS GREAT AS ON THE 6MRJA30 BEARING. ALSO YOU WILL FIND THAT THE ROLLERS ARE WIDER TRHAN USED ON THE 6MRJA30 BEARING SO, ASSIMING THE SAME INTERNAL CLEARANCE WITHIN A FEW DIFFERENT BEARINGS THE 6MRJA30 WILL ALLOW A TAD MORE FLEX THAN THE OTHERS AND WHEN CHECKING USED MAINS IT IS INTERESTING TO NOTE THAT THE WEAR PATTERN ON A 6MRJA30 BEARINGS ROLLERS DOES NOT QUITE REACH THE START OF THE END RADIUS BUT IT DOES ON ALL THE OTHERS I HAVE LOOKED AT INCLUDING THE FAG ONES.I WAS TOLD THAT THE ONLY REASON FOR THE CHANGE TO FAG BEARINGS WAS THAT THEY WERE DOWN THE ROAD FROM THE FACTORY AND THEY WERE CHEAPER. OR WAS IT THAT RHP DIDNT WANT TO MAKE A FEW SPECIALS IN SMALL QUANTITIES?
NOW FOR LATER BEARINGS I LOOKED AT A FEW YEARS BACK.
THE RHP NUP306ETN BEARING HAS 13 ROLLERS APPROX 12MM WIDE AND 11MM OD WITH A PARALLEL SECTION APPROX 9MM WIDE TAPERING TO APPROX 10.96MM BY THE START OF THE END RADIUS.DYNAMIC = 57000N. STATIC = 53000N.
A FAG NJ306E BEARING HAS 12 ROLLERS APPROX 12MM WIDE 11MM OD WITH A PARALLEL SECTION OF 8MM TAPERING TO 10.97MM BY THE START OF THE END RADIUS. DYNAMIC= 51000N AND STATIC =48000N.
OF COURSE THE MEASUREMENTS AND HAVING THE FRIENDLY GENT AT THE RHP OLD RANSOME AND MARLES FACTORY GO INTO THE CELLAR, FIND THE DRAWINGS AND CALCULATE THE LOAD VALUES FOR THE 8 AND 6 MRJA30 BEARINGS WAS A LONG TIME AGO NOW AND OTHER MANUFACTURERS BEARING MAY OF CHANGED SINCE THOSE DAYS BUT I WOULD SUGGEST THAT CONCENTRATING ON THE LOAD VALUES IS A RED HERRING AS THE BEARING THAT SORTED OUT THE PROBLEM ON THE 750S HAD LOWER LOAD VALUES THAN THE ONE IT REPLACED.......
WITH NOTHING SPECIAL IN THE SHAPES OF THE VARIOUS MANUFACTURERS BEARINGS THESE DAYS WHY DO PEOPLE INSIST ON CALLING THEM SUPERBLENDS???
OH YES.... AND GUESS WHO, MANY YEARS AGO, FOUND BEING FLOGGED AS SUPERLENDS A PILE OF FAGNJ
(OR WAS IT NU?) 306E BEARINGS THAT HAD STRAIGHT PARALLEL ROLLERS..... YES THATS HOW FAG USED TO PRODUCE THEM BEFORE CHANGING TO THE NEW SHAPED ROLLERS MANY YEARS AGO.......WONDER HOW MANY OWNERS BOUGHT THOSE BEARINGS AND BUGGERED THEIR ENGINES???
LUCKILY I FOUND HIDDEN, SOMEWHERE IN BIRMINGHAM, MANY YEARS AGO AMOUNG THE HUNDREDS OF BOXES EACH CONTAINING 8 X 8MRJA30 BEARING TWO BOXES MARKED 6MRJA30 AND BOUGHT THEM AT THE SAME 30 BOB EACH AS WAS BEING CHARGED FOR THE OLD CRAP (THE BALL RACE 6306S BALL BEARINGS WERE 20 BOB). ONES....THINK I HAVE TWO LEFT NOW.... THANKS TO FRIENDS NICKING THEM.
WONDER IF THE OLDE RANSOM AND MARLES FACTORY NOW ITS PART OF A JAPANESE GROUP STILL HAS ALL ITS ORIGINAL DRAWINGS SO PEOPLE CAN STILL PHONE UP AND FIND OUT THE SPEC OF THEIR WW1 FIGHTER AIRCRAFT MOTORS BEARINGS OR HAVE THEY ALL BEEN 'THROWN ON A BIG SKIP' AS I WAS TOLD WERE THE DRAWINGS AND CHANGE SHEETS FOR THE LAYCOCK ENGINEERING COMMANDO CLUTCH DIAPHRAGM SPRINGS BY GKN WHEN THEY CLOSED THEM DOWN?????.
SUGGESTED READING FOR ANYONE INTERESTED.IN FACT IT SHOULD BE COMPOLSORY READING FOR ALL NORTON OWNERS.
MOTOR CYCLE SPORT. JAN 77. PAGES 27 AND 28...''VICIOUS CIRCLE'' ' A CAUTIONARY TALE IN WHICH IT IS SHOWN THAT IN ENGINEERING, AT LEAST, NOTHING IS AS SIMPLE AS IT SEEMS. THE FOLLOWING STORY IS BASED ON A SERIES OF EVENTS WHICH TOOK PLACE NOT LONG AGO, AT A MOTORCYCLE MANUFACTURER SOMEWHERE IN EUROPE. ONLY THE NAMES HAVE BEEN OMITTED TO PROTECT THE GUILTY'.
READ IT AND CRY AT THE INCOMPETENCE THAT WAS NORTONS. ITS 100% FACT.
NO SPELL OR GRAMMER CHECKS APPLIED.
 
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A bit more bearing history: According to the US importers' (Berliner) local district rep (NJ), Norton put a cheap (why else!) Japanese ball bearing on the timing side in the '71 Commando's. They would fail at 8k miles. Of course, my bike was the first from the shop to go! I think I rebuilt every '71 we sold. No warranty coverage since none reached that mileage quick enough. As I recall, it was a Japanese bearing. In retrospect, it seems odd, since that was the period when British Industry was not allowed? to sorce parts outside the British Isles.
 
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There seems to be no end to the different manufacturers and types of main bearings that were used in Norton Commandos, especially early Commandos. Another data point: my '69 S-type had Hoover brand main bearings.

Jason
 

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main bearing

Jota,

You said "I rebuilt everyone we sold". Did you work for a Norton dealer - locally in Santa Clara valley?
 
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illf8ed,

Yes, I did. But not in that time frame. Was a mechanic in the early 70's at a shop in NJ. Carried Norton, Guzzi, Hodaka, Ducati... Combined auto repair/motorcycle dealer. Seasonal resort town.
Worked at a bike dealer in Santa Clara on El Camino Real. Cycle Sports? They carried Yamaha, BMW, Norton, Triumph, Guzzi, Ducati. About '77-'79. Parts Manager.

Just realized I should have introduced myself when I joined this Forum. Working on getting some photos digitized, (camera problem) so I can post them. I'll comment some when I get them uploaded.
 

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Cycle Sports in Santa Clara

Jota,

I rode my first '72 combat roadster from Riverside, Ca to home in Milpitas, Ca in June '73. There was something that it needed so dropped it at Cycle Sports for a day. A German guy ran the shop.

In '73 there were three shops selling Norton in the valley - Cycle Imports, Cycle Sports and Brooks Cyclery. Your old shop was one of the places one could buy a new, in the crate '74 Commando for something like $1495 in the late '70s.
 
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Hello all, I have identified the actual bearing numbers fitted to this bike.
6 with is put on with an electric pencil then MJRA 30 with RHP markings.

We believe these bikes have not ben apart before, so more than likely this is original fitment.

By the way the bearing show no evidence of wear. I was just planning on replacing the slippers and painting the cases in silver 2-pak.

Cheers Richard
 
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