Transmission Bearings

maaseyracer

maaseyracer

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Apr 28, 2015
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I'm looking for high-quality mainshaft bearings for my 1975 MK3 transmission. About 20-30K miles ago, I installed bearings from a popular Norton Supplier, but both mainshaft bearings are toast. Meanwhile, the bronze-cage layshaft bearing is still in perfect working order.

I know there are some decent bearings coming out of China, but sourcing is critical. The failed mainshaft bearings have no brand markings, and the seals are labeled "China."

Does anyone have a reliable source for reputable, steel-cage bearings? I've come across some plastic-cage options that fit, but that seems like a bad route. Any recommendations?
 
Last edited:
I have had a plastic caged SKF Layshaft roller in my 850 since 1986 and had no issues with it in all those years, unlike the Portuguese bearing it replaced.
 
marinatlas said:
www.rgmnorton.co.uk

GEARBOX MAINSHAFT (SLEEVE GEAR) BEARING, SHIELDED

A2/316 RGM NORTON 040098 0400981RZ
www.rgmnorton.co.uk

Are you looking for the sleeve gear bearing or the other mainshaft one ? or layshaft ??

andover-norton.co.uk

Andover Norton - SLEEVE GEAR BEARING (ONE SEAL) use 04.0098 for OPEN option - A2/316

SLEEVE GEAR BEARING (ONE SEAL) use 04.0098 for OPEN option
andover-norton.co.uk
Click to expand...

Looking for the main shaft bearings, both sleeve and outter case. I settled on the poly caged layshaft bearing, though wish there was a better option. That KSM bearing listed on Andover is a really low grade Koyo bearing. The RGM bearing looks like the cheap bearing that failed in my case.

L.A.B. said:
If there's one bearing that should be changed, then it's the Portuguese brass cage layshaft bearing as it can injure or even kill you when it fails. It's really not worth the risk unless you like living dangerously.
Click to expand...

Those had been replaced.

kommando said:
I have had a plastic caged SKF Layshaft roller in my 850 since 1986 and had no issues with it in all those years, unlike the Portuguese bearing it replaced.
Click to expand...

I am referring to plastic caged ball bearings. Unfortunately I am not seeing anything but poly cages for the roller.
 
maaseyracer said:
Looking for the main shaft bearings, both sleeve and outter case. I settled on the poly caged layshaft bearing, though wish there was a better option. That KSM bearing listed on Andover is a really low grade Koyo bearing. The RGM bearing looks like the cheap bearing that failed in my case.



Those had been replaced.



I am referring to plastic caged ball bearings. Unfortunately I am not seeing anything but poly cages for the roller.
Click to expand...
May just be me, but I'm confused at which bearing are "plastic caged ball bearing". None of the ball bearings in a Norton gearbox should have plastic or poly cages.

There are three bearing in the gearbox.

Drive side layshaft bearing should be a roller bearing and the one AN sells is excellent.

Drive side sleeve gear bearing. Standard numbers 1654 (open) or 1654-1RS (04-0098|A2/316). AN sells both and they are fine. The 1654-1RS is really 1654-2RS with one seal removed. AN used to sell the one steel shield type, but they are impossible to find in a quality brand. This is a common bearing. I normally use the A2/316 from AN but I've tested the uxcell bearing which is made in China and sold on Amazon - I've found nothing wrong with them.

Timing side main shaft ball bearing. RLS5. The AN bearing is quality (04.0099), I use the one from the US company PGN. I have no idea where they are actually manufactured but they seem to be identical quality to those sold by AN
 
marshg246 said:
May just be me, but I'm confused at which bearing are "plastic caged ball bearing". None of the ball bearings in a Norton gearbox should have plastic or poly cages.

There are three bearing in the gearbox.

Drive side layshaft bearing should be a roller bearing and the one AN sells is excellent.
Click to expand...
The layshaft roller bearing is a good, safe replacement, but does not manage end float, so shimming is required.
This has caused me issues in the past, partly because there are no thrust faces designed in where the shims are placed.
The 6203TB is a better replacement, since it positively locates the layshaft. It has a phenolic cage, which allows for the inevitable layshaft flex (which destroys the cage of the standard bearing).
Lots of prior threads on the subject.

DogT

Thread 'Hemmings Layshaft bearing'

What's the deal here. I thought "Portugal" was the dreaded bearing that was supposed to be replaced? I just got this from Mick today.

Hemmings Layshaft bearing


Dave
69S
 
marshg246 said:
May just be me, but I'm confused at which bearing are "plastic caged ball bearing". None of the ball bearings in a Norton gearbox should have plastic or poly cages.

There are three bearing in the gearbox.

Drive side layshaft bearing should be a roller bearing and the one AN sells is excellent.

Drive side sleeve gear bearing. Standard numbers 1654 (open) or 1654-1RS (04-0098|A2/316). AN sells both and they are fine. The 1654-1RS is really 1654-2RS with one seal removed. AN used to sell the one steel shield type, but they are impossible to find in a quality brand. This is a common bearing. I normally use the A2/316 from AN but I've tested the uxcell bearing which is made in China and sold on Amazon - I've found nothing wrong with them.

Timing side main shaft ball bearing. RLS5. The AN bearing is quality (04.0099), I use the one from the US company PGN. I have no idea where they are actually manufactured but they seem to be identical quality to those sold by AN
Click to expand...

When going to various bearing suppliers I have only found 1654 and RLS-5 bearings with plastic/nylon cages from reputable suppliers, these are not poly cages like found on roller bearings.

The bearings offerings from your recommended supplier have both failed in my transmission. I just, setup the the transmission in the mill and checked the bearing alignment with a co-axial indicator, surprisingly good for a british bike. I have check the shafts for straightness and we are good. This was just bearing failure.

I am not having layshaft bearing issues. I would like to know if anyone has a reasonable source or alternative for these junk bearings.

B+Bogus said:
The layshaft roller bearing is a good, safe replacement, but does not manage end float, so shimming is required.
This has caused me issues in the past, partly because there are no thrust faces designed in where the shims are placed.
The 6203TB is a better replacement, since it positively locates the layshaft. It has a phenolic cage, which allows for the inevitable layshaft flex (which destroys the cage of the standard bearing).
Lots of prior threads on the subject.
Click to expand...

I am not looking for layshaft bearings, I have sourced them from a reputable bearing manufacturer.
 
B+Bogus said:
The layshaft roller bearing is a good, safe replacement, but does not manage end float, so shimming is required.
This has caused me issues in the past, partly because there are no thrust faces designed in where the shims are placed.
The 6203TB is a better replacement, since it positively locates the layshaft. It has a phenolic cage, which allows for the inevitable layshaft flex (which destroys the cage of the standard bearing).
Lots of prior threads on the subject.

DogT

Thread 'Hemmings Layshaft bearing'

What's the deal here. I thought "Portugal" was the dreaded bearing that was supposed to be replaced? I just got this from Mick today.

Hemmings Layshaft bearing


Dave
69S
Click to expand...
When you take apart a gearbox with a layshaft ball bearing, if the layshaft comes out easily then it is not managing end float. To manage end float, they must be tight in the case and tight on the shaft - royal PITA to get apart. With the roller bearing, it is good to shim but you must be sure the shim(s) sits flat on the kickstart. The shims most use must be slightly opened up on the inside (I use a Dremel for a few seconds). IMHO, a small amount of end float is a good thing.
 
maaseyracer said:
Those had been replaced.
Click to expand...
Those? There's only one layshaft ball bearing. Are you saying you replaced the original brass cage ball bearing with another brass cage bearing? If not then I don't understand what you mean in your first post. That bearing should be replaced with either the NJ203E roller bearing or 6203TB ball bearing B+Bogus mentioned.

andover-norton.co.uk

Andover Norton - LAYSHAFT ROLLER BEARING (18337) (B2/322) - 06.7710

LAYSHAFT ROLLER BEARING (18337) (B2/322)
andover-norton.co.uk
 
maaseyracer said:
When going to various bearing suppliers I have only found 1654 and RLS-5 bearings with plastic/nylon cages from reputable suppliers, these are not poly cages like found on roller bearings.
Click to expand...
The "cage" is the thing that separates the balls inside the bearing and in every 1654 or RLS5 I've ever seen the cage was steel. Maybe you're talking about the steel shield or plastic seal. Finding quality steel shields is hard. A shield is a "no-touch" so in a Norton gearbox does not keep oil in. A seal does touch the inner and outer races so does keep oil in.
 
marshg246 said:
The "cage" is the thing that separates the balls inside the bearing and in every 1654 or RLS5 I've ever seen the cage was steel. Maybe you're talking about the steel shield or plastic seal. Finding quality steel shields is hard. A shield is a "no-touch" so in a Norton gearbox does not keep oil in. A seal does touch the inner and outer races so does keep oil in.
Click to expand...
Not going to run and SKF that looks like this. I suspect you would not either.

Transmission Bearings



L.A.B. said:
Those? There's only one layshaft ball bearing. Are you saying you replaced the original brass cage ball bearing with another brass cage bearing? If not then I don't understand what you mean in your first post. That bearing should be replaced with either the NJ203E roller bearing or 6203TB ball bearing B+Bogus mentioned.
Click to expand...

I think there may be some miscommunication. As I mentioned earlier, I replaced the bearings 20-30K miles ago with non-factory bearings from a well-known Norton supplier. So the original Portuguese bearings are no longer in play.

To clarify, I just bought a FAG NJ203 with a poly cage. My only comment was my high quality brass cage layshaft bearing is still in good condition, but the mainshaft bearings are toast.
 
maaseyracer said:
Not going to run and SKF that looks like this. I suspect you would not either.

Transmission Bearings
Click to expand...
Correct - I would not. The balls are only in partial "cages", nothing like standard steel cages. I assume that is light duty bearing. What are all the numbers on it?
 
marshg246 said:
Correct - I would not. The balls are only in partial "cages", nothing like standard steel cages. I assume that is light duty bearing. What are all the numbers on it?
Click to expand...

That is an SKF 1654. The bearing supplier says most of the 1654 bearings are light duty these days from the major manufacturers.

I suspect that is why we see these low quality bearings on the market as they are the “best” option in these circumstances.
 
maaseyracer said:
That is an SKF 1654. The bearing supplier says most of the 1654 bearings are light duty these days from the major manufacturers.

I suspect that is why we see these low quality bearings on the market as they are the “best” option in these circumstances.
Click to expand...
When a bearing is simply marked 1654 it should be considered unusable as it is not certified to any standards and is simply more or less the right size.
If it includes ABEC-1 it is usable in most automotive applications. May not actually be certified by ABEC.
ABEC-3 is more precise in dimensions and IMHO is what the sleeve gear bearing needs to be and is tested and certified by ABEC.
Higher ABEC numbers, IMHO, are overkill.

ABEC-3 is sometimes called "electric motor quality".

See more info here: https://axisbearing.com/abec-rating-for-bearing-selection/
 
marshg246 said:
When a bearing is simply marked 1654 it should be considered unusable as it is not certified to any standards and is simply more or less the right size.
If it includes ABEC-1 it is usable in most automotive applications. May not actually be certified by ABEC.
ABEC-3 is more precise in dimensions and IMHO is what the sleeve gear bearing needs to be and is tested and certified by ABEC.
Higher ABEC numbers, IMHO, are overkill.

ABEC-3 is sometimes called "electric motor quality".

See more info here: https://axisbearing.com/abec-rating-for-bearing-selection/
Click to expand...

Those KSM bearings are ungraded Koyo bearings the made in china bearings are ungraded as well. It would be nice to get an abec 3 or higher rated bearing. Over abec 3 can be diminishing return on a stock transmission. On a low friction transmission there is more potential for reasonable friction savings with a higher abec rating.

Sounds like you are coming to the same conclusion I came to. These are low quality bearings are not a great option.
 
marinatlas said:

AXIS 1654-ZZ Bearing | ABEC 3 Shielded 1654-ZZ Ball Bearing

AXIS 1654-ZZ Bearing is a premium ABEC 3 precision shielded deep groove 1654-ZZ ball bearing. AXIS 1654-ZZ bearings use grade 10 balls and Polyrex EM bearing grease for optimal lifespan!
www.usarollerchain.com

So , here is one , is that OK ?
Click to expand...
Possibly. I reached out to them about who makes the bearings. They. Require a $300 minimum order so I want to be sure before I order. I also reached out to NTN and SKF about a custom batch order.
 
marinatlas said:

AXIS 1654-ZZ Bearing | ABEC 3 Shielded 1654-ZZ Ball Bearing

AXIS 1654-ZZ Bearing is a premium ABEC 3 precision shielded deep groove 1654-ZZ ball bearing. AXIS 1654-ZZ bearings use grade 10 balls and Polyrex EM bearing grease for optimal lifespan!
www.usarollerchain.com

So , here is one , is that OK ?
Click to expand...

Quick update on these, the bearing company that makes these cannot confirm that they are ABEC 3 rated, and US Roller Chain is not sure if they even have them in stock. I spoke to SKF this morning they are looking into if they can do a batch at a "reasonable" quantity.
 
Well, this took a turn. While cleaning out the transmission, and readying it for reassembly I found this questionable work hidden under a generous amount of what looks like bearing retainer or Loctite. While I fully admit when I screw things up, this one isn’t me. The parts sourcing is my fault as I sourced the parts, but had the local "expert" handle the work since I didn’t have the tooling or time when I got the bike. From the previous owners receipts, it looks like another well-known local expert worked on the bike in the ‘80s and ‘90s, so I’m not sure who to thank for this one. At the same while this is not pretty, it was inline with the other mainshaft bearing and perpendicular to the face of the case so I am still going to lean towards bearing failure. But when you see something like this the plot thickens.

My game play now is to convert this to a roller bearing.

If anyone knows the bore spacing between the layshaft and main shaft and can share that info that would be greatly appreciated.

Transmission Bearings
 

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