Superblend bearing profile

J. M. Leadbeater · Dec 5, 2015

Re that NSK bearing shown ...With an outer raceway that thin surely when shrunk into the cases the outer raceway will close up reducing or removing entirely the 0.0006 - 0.001 inch internal clearance the bearing requires for correct lubrication????????.
Once watched a gent apply Loctite to the outer raceway main on his 7R AJS and drop it into the hot case.....when he came to install the crank fitted with the bearings inner raceway and rollers the two would not fit together.....loctite has its uses but not in such situations.

Rohan · Dec 5, 2015

J. M. Leadbeater said:
Re that NSK bearing shown ...With an outer raceway that thin

The NSK bearing shown, for a dommie, the outer race isn't shown ???
Thats only the inner race and rollers and cage.
What were you thinking - or drinking !

P.S. Isn't the C3 clearance specified for these so that the shrinkage doesn't squeeze the bearings so hard that it distorts the races.
So they can be installed quite tight in the cases and on the shafts, and not suffer any consequences.

kommando · Dec 5, 2015

P.S. Isn't the C3 clearance specified for these so that the shrinkage doesn't squeeze the bearings so hard that it distorts the races.

No its to ensure the clearance is correct after the races have been reduced by being squeezed by the cold alloy or expanded by being pressed on the crank as both actions reduce the clearance.

So they can be installed quite tight in the cases and on the shafts, and not suffer any consequences.

As long as the free clearance in the free state is correct then yes they will not suffer any consequences after the install, if after the install the crank will not turn by hand the clearance is too tight and the rollers will skid until the engine heats up and the clearances ease as the cases expand the their grip reduces, every time the engine cools they will skid again on start up and rapid wear will set in.

Rohan · Dec 5, 2015

Just for illustration, the full drive side roller bearing for a dommie.

Note that these are N306 bearings (NOT NJ306 = no collar), the rollers can float across the entire outer track with no restraint.
Dommies use a ball bearing on the timing side to locate the crank.
Dimensionally any 306 are all the same external dimensions.

These are about $10 each (with discount, like all customers get)(less in quantity)(even less on the internet), how much were superblends again ?
That extra roller and collar sure costs...

Rohan · Dec 5, 2015

P.S. Isn't the C3 clearance specified for these so that the shrinkage doesn't squeeze the bearings so hard that it distorts the races.

kommando said:
No its to ensure the clearance is correct after the races have been reduced by being squeezed by the cold alloy or expanded by being pressed on the crank as both actions reduce the clearance.

??
Isn't that saying EXACTLY the same thing, almost same words even.

Or have I missed something.

kommando · Dec 5, 2015

Its the word distort and what it implies. It doesn't distort them as they are still round, the word distort would imply they became oval but they are still round just smaller.

distort
dɪˈstɔːt/Submit
verb
1.
pull or twist out of shape.
"a grimace distorted her fine mouth"
synonyms: twist, warp, contort, bend, buckle, deform, malform, misshape, disfigure; More

Rohan · Dec 5, 2015

The ONLY way they could lose that clearance is if the races distort.....

kommando · Dec 5, 2015

They retain their shape and are round but smaller for the outer ring or larger for the inner ring, distortion means they loose their shape. Shrink or expand is not distortion.

Rohan · Dec 5, 2015

kommando said:
Shrink or expand is not distortion.

Oh.
Sometimes.

Or is that always ?

xbacksideslider · Dec 8, 2015

Great thread, and Paddy, a great story from the past.

Paddy_SP · Dec 9, 2015

xbacksideslider said:
Great thread, and Paddy, a great story from the past.

Thank you!

Biscuit · Dec 9, 2015

This IS a great thread and paddy's story was super (blend?).

Since location info on a lot of posters is not always evident, I can't say for sure but I believe what part of the world we live in contributes to interesting discussions such as this one this time of year. Those of us who live in the cold harsher winter climes and have quit riding for a bit enjoy thinking about such things as what makes a bearing happiest in out engines. It's a good topic and keeps us harmlessly busy and connected. While those in warmer climes are riding. :mrgreen:

Paddy_SP · Dec 10, 2015

Biscuit said:
This IS a great thread and paddy's story was super (blend?).

Thanks again!

74ok · Dec 28, 2015

:lol:

comnoz said:
pete.v said:

I really think that "Superblend" is sort of a 70's thing. They could have called it the "Mellow out" bearing or "The Groovy Smoothy" or perhaps the "Shagadelic". Hows about the "Bitchin" or the "Boogie" bearing.
Someone got high and said, " Man oh man, that bearing is super blend......grooooooovy!"

Click to expand...

Pete, have you been hanging out with Steve?

comnoz · Feb 19, 2016

Well I came up with a NOS 1972 "superblend" and repeated my measurements.

Here is the result.

[video]https://www.youtube.com/watch?v=JcR_1ZbtUdw[/video]

L.A.B. · Feb 19, 2016

comnoz said:
Well I came up with a NOS 1972 "superblend" and repeated my measurements

MRJA30 is the standard pre-Superblend bearing.

The Superblend is supposed to be 6 MRJA30.

comnoz · Feb 19, 2016

L.A.B. said:
comnoz said:

Well I came up with a NOS 1972 "superblend" and repeated my measurements

Click to expand...

MRJA30 is the standard pre-Superblend bearing.

The Superblend is supposed to be 6 MRJA30.

That may be correct. I am not real sure when they started with the "superblend" name and I have read differing opinions as to that.

Does anyone have a 6 MRJA30 that I could destroy and measure?

L.A.B. · Feb 19, 2016

comnoz said:
I am not real sure when they started with the "superblend" name

Service Release N.2/9 August 1972

EXPLANATION:
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).

ACTION: Where engine units are stripped for examination, or the need for main bearing replacement, fit only roller main bearings part number 063906 in place of the previously specified 063114.

comnoz said:
and I have read differing opinions as to that.

Hardly surprising, as the FAG NJ306E is often thought of as being the "Superblend" bearing.

http://lansdowne2.dh.bytemark.co.uk/Plo ... e-releases

Prior to 1971, crankshaft main bearings comprised a roller drive side bearing (R&M Part No. MRJA30) and a timing side ball bearing (Part No. MJ30). Later models are fitted with two new type roller bearings (Part No. 6MRJA30) that give improved durability. These bearings can be fitted to earlier models on both the drive and timing side. When roller bearings are used on both sides, the crankshaft should be shimmed to provide an end play of between 0.010" and 0.020". This is Norton shim (Part No. NMT2196A, later changed to 067569).

SERVICE RELEASE No.68 October 1971:

Explanation
We are introducing a new roller main bearing arrangement in production almost immediately. The fitting of this bearing arrangement reduces overall width between the main bearings and increases timing side main bearing journal diameter.

For service purposes we shall in future supply only the crankshaft of the latest size, Part No. 063106. The main bearings, Part No. 063114, must be used in conjunction. The new bearings are 2 dot single lip roller bearings and should be assembled with the lip into the crankcase in both cases. Main bearing Part No. 063114 is of the Ransomes type (R&M) MRJ A30.

comnoz · Feb 19, 2016

What I do know is the FAG NJ306E was the first bearing that gave long life to a bike that was used hard.

And, it did it just because of the very high load capacity -not because of rollers with a tapered profile. Jim

kommando · Feb 20, 2016

If you read the Nasa pdf it states that more crowning is added to the rollers as the capacity is increased, so by using a higher than needed capacity you get more crowning eg taper or chamfer at the edge. So the NJ 306E came with more crowning out of the box and luckily coped better with the roller inner twisting due to the centrally unsupported crank acting like a skipping rope at high revs. The NJ306E is mentioned in the oct 71 factory service sheet along with 5 other bearings, so it was available before the R&M 6/MRJA30 but not yet recognised in Sept 72 as being equivalent in durability.

Superblend bearing profile

J. M. Leadbeater

Rohan

kommando

Rohan

Rohan

kommando

Rohan

kommando

Rohan

xbacksideslider

Paddy_SP

Biscuit

Paddy_SP

74ok

comnoz

L.A.B.

Moderator

comnoz

L.A.B.

Moderator

comnoz

kommando

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