Who has fitted superblend bearings to early commando?

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Dean said:
Hi Dave

Happy coincidence .... I am just doing my 68 now. S/n 128372. I went thru the same thoughts and decided that if I am going to the trouble of overhauling the motor may as well put in the best upgrades that I can. What I am going for is a street bike that is reliable. I am not into riding everywhere flat out but I want to know if I want to " open her up " I can. There is nothing worse than riding and worrying if some part is going to fail because it wasn't up to the task.

This morning I fitted the new superblend bearings and measured end float. Got 0.017" (no shims) so am happy with that, going on what Jim has said and considering that 850 motor end float is 0.010 - 0.024" and it is basically the same bottom end set up. ( I'm sure someone will correct me here if I'm wrong...)

So happy days. Progre$$ :D

What is the S/N of your bike. Just wondering how close it is to mine.

Cheers Dean
Click to expand...

Fingers crossed that I get that lucky. :) Ours could've been mates on the same boat (if you're in the US . but I'm guessing you're in the UK?) My # is 128279

Spliting the cases last night found that the lower bolt hole that holds the inner primary to the drive side must've had a major pullout at sometime as it was welded back up. You couldn't see it on the outside w/o a magnifying glass but on the inside it was obvious. (The joy of taking on a bike that you didn't own for the first 44 years of it's life. :) )

Overall everything looks pretty good . .my cam isn't as "highly polished" on the lobes as I'd have expected but I haven't looked at it close enough to see if it's just tarnish from sitting or not. I know my pistons are being replaced and the big dilemma I'm having right now is the con rods . .it looks to me like the prior owner wasn't real careful and let them hit the sides of the cases at some point. On one it has a mark (nothing that will catch a fingernail, but on the other there's a mark that will catch a fingernail) Arguing with myself if it's paranoia and I should just polish them out or if I should be safe and spend the extra $ while I'm in here . . .

Have a good one,
Dave
 
Hi again Dave,

Yes it sounds like our bikes would have been "class mates" I got my bike off Craig's list. It was in Colorado when I bought it but had a Kansas plate and was last registered in 1986. The guy I got it off said it came out of a barn and he had it about 2 years but didn't do anything with it. I had it shipped to my home in Abu Dhabi (1hr from Dubai in the UAE)

My conrods were coroded on the small end as well as the crank journals had surface corrosion. Cleaned up the crank with a grind to -0.010 then I put both rods on one piston pin and make sure the big ends are not twisted. Check both sides. Once I also checked all the measurements I polished them up then balanced the weights to within 1 gram including the moment weights of both ends. Takes a bit of time but I was on a cargo flight for work so had 16 hrs to sit and polish them. Think they came out pretty nice. Have read up on the rods and for normal use the seem to have no problems so I think if you polish out any damage they will be fine.

My camshaft bushes measured up bang on size, so if they are ok I would leave them. It's not something you can change at home. The lobes on mine polished up nice with a bit of 600 wet and dry with WD40. If your cam is the same as mine. it is P/N 22729 and has same lift on inlet and exhaust. ( later had higher lift on inlet) I think it is the same as atlas cam.

Also what did you do with your frame. I modified mine same as later. I crack checked it and found R/H down tube cracked about 3/4 of the way round about 3" down from where it joins the headstock. Ready to part company....

So cool to be talking to someone restoring the same bike only about 100 away from mine 45 years after they were built.
Goes to show what a great site this is...

Cheers
Dean
 

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Those are pretty! I still have the widowmaker frame and it'll go to the next owner but the bike also came with a 70 frame that I've powdercoated and reinforced and that what I'll be riding. (Need to figure out how to host pics and post here)
 
comnoz said:
I would not worry about shimming the crank unless the end play ended up being over .035 in or so. None were shimmed from the factory with Superblends.

If you decide to install shims the install them between the bearing and the case.

You may be able to get by with a shim between the timing side bearing and the crank but if you install a shim between the drive side bearing and the crank it will usually come out sooner or later and cause much damage. There is nothing to keep it pinched tightly between the bearing and crank like there is on the timing side. Jim
Click to expand...

I hadn't been warned about that, but luckily, it was the timing side which I fitted the 10 thou shim.
I think I will make up some of those dummy bearings to go with the 3 sets of S/B's I have waiting to be used.
Dereck.
 
I just measure them with a large pair of calipers.

You don't want to reduce the end play too much. The crank gets wider as the RPM's climb.

For a racebike engine I use at least .020 clearance. Less than that and they will show distress on the ends of the rollers after revving the snot out of them for a while.

Street bikes will live OK at .010 or .015 in -or at .040. Jim
 
Just to save some confusion, I got a PM from new member Pesky asking about the Superblend picture I posted in this thread.
He was confused about the NU designation.
This is an original bearing from my 1974 Mk2a, the outer races were stamped NU but the inner's were stamped NJ maybe not clear in the picture.
The inner is what defines a 'superblend so got the NJ designation.

Who has fitted superblend bearings to early commando?
 
Time Warp said:
Just to save some confusion, I got a PM from new member Pesky asking about the Superblend picture I posted in this thread.
He was confused about the NU designation.
This is an original bearing from my 1974 Mk2a, the outer races were stamped NU but the inner's were stamped NJ maybe not clear in the picture.
The inner is what defines a 'superblend so got the NJ designation.

Time Warp,
I concur with that Superblend pic as my stash of Mains and what came out of my 72 Combat was marked as such.
Cheers,
Thomas
CNN
Click to expand...
 
Time Warp said:
This is an original bearing from my 1974 Mk2a, the outer races were stamped NU but the inner's were stamped NJ maybe not clear in the picture.
The inner is what defines a 'superblend so got the NJ designation.
Click to expand...

This has been cropped up before a couple of times, as some FAG NJ306E bearings do seem to have NU stamped on the outer race, the outer component being the same for both FAG NU306E and NJ306E bearing types.
 
the NJ on the inner race just signifies it is a single flange race.
 
I thought that is what I said, guess not.
NJ and NU outer's are the same, a double captive roller.
In the case of the Norton Commando the inner has to be a NJ in superblend form because in pairs with no inner flange the crank would walk unlike the MRJ and ball bearing timing side previously.


You might then ask why was a NU outer used in the Commando when that is a floating inner race bearing (as a off the shelf unit) even if the outer is double captive like the NJ.
A NU inner would be marked NU so a 'superblend in this case can be identified by the NJ stamping more so than the outer in this case NU/NJ.
Perhaps the recalls were more major than reported, to the point that they used the NU stamped outer races to complete NVT requests. (unless there is a FAG RNU outer)

What I still find very interesting is there are still questions to be answered regarding British motorcycles in general, some may never be solved even though there were many documents and people involved at the time. (Long before the internet of course)
Somewhere out there (but the clock is ticking) there are people who might very well say... Ohhh that,well, it was like this...................
 
I was thinking a little of the MRJ bearings also both Triumph and Norton.
Was there a clipped roller (superblend) MRJ, what was the one with the engraved number prefix or I might be confusing Triumph MRJ's again.
I have some somewhere along with other NOS MRJ 30's.
 
Time Warp said:
Perhaps the recalls were more major than reported, to the point that they used the NU stamped outer races to complete NVT requests.
Click to expand...

I'm not aware of any factory "recalls" to fit 'Superblend' bearings and all 850s had the FAG NJ306E bearings from the off, as far as I know?

We know a reasonably large number of Combats were returned to the factory to be detuned, but whether any of those Combats were rebuilt with Superblends is I believe, unknown, however, any Superblends fitted during that period to the 750 models would almost certainly have been the actual R&M 6/MRJA30 'Superblends' which are an 'NF' (rollers held captive on the inner race and single lip outer) type bearing.
 
So all Combats with failed crankshaft bearings retained the timing side ball bearing (if they had one) or both were replaced with two engraved 6 /MRJA30's with the secret superblend (clipped) rollers.

Given the number of projected 850's for 1973 on that might explain the NU outer races.
 
Time Warp said:
So all Combats with failed crankshaft bearings retained the timing side ball bearing (if they had one) or both were replaced with two MRJA30's with the secret superblend (clipped) rollers.
Click to expand...

As far as I'm aware, and according to the factory service notes (Oct. '71) and 1972 parts book, all '72 Commandos were fitted with two MRJA30 roller bearings prior to the introduction of the 6/MRJA30 Superblends (supposedly from serial 211891, thus post-Combat era).

Time Warp said:
Given the number of projected 850's for 1973 on that might explain the NU outer races.
Click to expand...

I'm sure we've seen examples of rather later German manufactured FAG 'NJ' bearings with NU marked outer races, so I don't think that is necessarily the case.
 
comnoz said:
I would not worry about shimming the crank unless the end play ended up being over .035 in or so. None were shimmed from the factory with Superblends.

If you decide to install shims the install them between the bearing and the case.

You may be able to get by with a shim between the timing side bearing and the crank but if you install a shim between the drive side bearing and the crank it will usually come out sooner or later and cause much damage. There is nothing to keep it pinched tightly between the bearing and crank like there is on the timing side. Jim
Click to expand...

Re shimming the bearing by using a OD sized shim between the outer race and the crank case...

Does it matter which crank case half you put the shim? Is there any reason not to put it in the drive side case?
 
L.A.B. said:
Time Warp said:
Perhaps the recalls were more major than reported, to the point that they used the NU stamped outer races to complete NVT requests.
Click to expand...

I'm not aware of any factory "recalls" to fit 'Superblend' bearings and all 850s had the FAG NJ306E bearings from the off, as far as I know?
Click to expand...

Reminds me of a discussion I had with T. C. Christensen (of Sunset Motors, Wisconsin) years ago about the Combat saga. He said his shop would pull new unsold Nortons out of crates and replace the main bearings in around 3.5 hours! He had the process down to a science. He may have only replaced the drive side bearing. I forget the details.
 
Fast Eddie said:
comnoz said:
I would not worry about shimming the crank unless the end play ended up being over .035 in or so. None were shimmed from the factory with Superblends.

If you decide to install shims the install them between the bearing and the case.

You may be able to get by with a shim between the timing side bearing and the crank but if you install a shim between the drive side bearing and the crank it will usually come out sooner or later and cause much damage. There is nothing to keep it pinched tightly between the bearing and crank like there is on the timing side. Jim
Click to expand...

Re shimming the bearing by using a OD sized shim between the outer race and the crank case...

Does it matter which crank case half you put the shim? Is there any reason not to put it in the drive side case?
Click to expand...

On a race motor I try to center the crank throws under the cylinder bores.
For the street this is likely overkill. I usually just split the shims evenly between left and right. Jim
 
comnoz said:
Fast Eddie said:
comnoz said:
I would not worry about shimming the crank unless the end play ended up being over .035 in or so. None were shimmed from the factory with Superblends.

If you decide to install shims the install them between the bearing and the case.

You may be able to get by with a shim between the timing side bearing and the crank but if you install a shim between the drive side bearing and the crank it will usually come out sooner or later and cause much damage. There is nothing to keep it pinched tightly between the bearing and crank like there is on the timing side. Jim
Click to expand...

Re shimming the bearing by using a OD sized shim between the outer race and the crank case...

Does it matter which crank case half you put the shim? Is there any reason not to put it in the drive side case?
Click to expand...

Thanks Jim. My reason for asking is that I will be double checking my end float this winter and if its too much, it would be easier to fit to the drive side as the timing case contents could all be left in situ!

Does excessive end float cause any specific abnormal noises on these motors?

On a race motor I try to center the crank throws under the cylinder bores.
For the street this is likely overkill. I usually just split the shims evenly between left and right. Jim
Click to expand...
 
The only problem I have seen with excessive endfloat is the possibility that back of the belt drive sprocket may rub on the case.

If it had way too much end float then I suppose you could have contact between the small end of the rod and the inside of the piston but it would have to be pretty extreme..

Not enough endfloat causes more problems that too much -from what I have seen. I have taken engines apart that were set at .005 and found the ends of the rollers turned blue. Jim
 
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