Clutch hub bearing

concours · Nov 24, 2023

Madnorton said:
The question has been asked many times in the past, what is the difference. 'One dot' these markings can be seen on old bearings, confusing as on some it is a dot '.' and some it is a hard to see lightly etched round 'O' This is not the whole story, bearing clearance specifications back in the 70's were not actually formalised it seems, and even today the clearance standard is still not consistent, I believe Japanese manufacturers use their own. Bearing standards that are seen usually relate to the fitting of the shaft and housing clearances in which they fit, great, but the clearance specifications can still overlap, so the bottom end of the normal clearance can also be in the loose end of the C2 clearance of a different manufacturer. That is why most bearing manufacturers insist that customers look at the data they provide for their bearings for the specific purpose, one manufacturer could differ from another.

Clutch bearings, the drawing was originally 'one dot' but then amended to C2. I like Greg have found no way to see how these compare, even our well renowned globally recognised supplier of bearings can't compare the old with the new. However, in recent days something has come to light which is seen in some of the posts above 'where do you get a C2 bearing from' considering we tried the bearing suppliers we deal with and the manufacturers of Japanese made bearings. This has indicated that there are some C2 bearings which are old stock still about, but how much!! None of the manufacturers or suppliers could provide a regular source of new C2 bearings from stock. So, if you have a C2 bearing fitted the chances are that if you paid through the nose for it then it could be a decent NOS bearing, if not then best of luck. The good news is there seems to no one jumping up and supplying knock offs (at the moment)

So what bearing to fit? back in the 70's in times of loose manufacturing tolerances a C2 most probably covered all bases in that it would fit and last. the standard bearings have been around for ages and numerous have been fitted, and the miles that have put on these suggest there is actually no issues whatsoever in using a bearing with normal clearance. The actual use the clutch bearing will see is most probably minimal compared to its service life cycle, these days they are well tested. So what if you have an original bearing and it is in good condition, simple, clean it and use it, it has most probably got more life left in it than some of us owners.

That is "assuming" all current owners dawdle about at parade speeds, and are too aloof to feel that heavy clutch assembly orbiting around, like an out of balance washing machine.

marshg246 · Nov 24, 2023

concours said:
That is "assuming" all current owners dawdle about at parade speeds, and are too aloof to feel that heavy clutch assembly orbiting around, like an out of balance washing machine.

You lost me. Only when the clutch is disengaged does the clutch bearing have anything to do.

concours · Nov 24, 2023

marshg246 said:
You lost me. Only when the clutch is disengaged does the clutch bearing have anything to do.

That is inaccurate.

marshg246 · Nov 24, 2023

concours said:
That is inaccurate.

Nope! The clutch basket is locked to the clutch center when the clutch is engaged and the bearing is not turning.

Madnorton · Nov 24, 2023

concours said:
That is "assuming" all current owners dawdle about at parade speeds, and are too aloof to feel that heavy clutch assembly orbiting around, like an out of balance washing machine.

I'll assume that the majority of all current owners do exactly that.

concours · Nov 24, 2023

marshg246 said:
Nope! The clutch basket is locked to the clutch center when the clutch is engaged and the bearing is not turning.

THAT part is accurate.

concours · Nov 24, 2023

Madnorton said:
I'll assume that the majority of all current owners do exactly that.

WHY would you assume that?

marshg246 · Nov 24, 2023

concours said:
THAT part is accurate.

What part isn't? Keep in mind that this is thread about clutch bearings and specifically the bearing clearance. Any clutch wobble when the clutch is engaged is not a function of the clutch bearing.

concours · Nov 24, 2023

marshg246 said:
What part isn't? Keep in mind that this is thread about clutch bearings and specifically the bearing clearance. Any clutch wobble when the clutch is engaged is not a function of the clutch bearing.

That is inaccurate.

Madnorton · Nov 24, 2023

concours said:
WHY would you assume that?

I suspect many don't see 80mph on their bikes, in the UK and other parts or europe on the road you would most probably end up dead, tangled up with deer, loss of licence with speeding fines, or in some countries bike confiscated and crushed.

marshg246 · Nov 24, 2023

concours said:
That is inaccurate.

You are wrong.

concours · Nov 24, 2023

concours said:
That is inaccurate.

Greg, my replies are attempting stimulate thought, and get you to consider that, you may not be fully aware of some things.

That clutch basket/sprocket, bunch of steel plates, pressure plate, diaphragm spring all orbiting about, known as runout, (nicknamed "wobble") when the clutch is disengaged.
You agree on that part.

When the clutch is engaged, that RUNOUT position is locked in place by the plates.
A random position. The heavy clutch assembly, significantly off center shakes like a whore in church. I've observed it. I can feel it through the footpegs. I regularly "adjust it" while underway to try and get a slightly better chance/random position.

So, the clutch basket bearing ABSOLUTELY affects the clutch runout while engaged.

Best to keep the runout as small as possible. Because it is there while underway, beating up the sleeve gear bushes, and the sleeve gear bearing.

concours · Nov 24, 2023

marshg246 said:
You are wrong.

So you say.

marshg246 · Nov 24, 2023

concours said:
Greg, my replies are attempting stimulate thought, and get you to consider that, you may not be fully aware of some things.

That clutch basket/sprocket, bunch of steel plates, pressure plate, diaphragm spring all orbiting about, known as runout, (nicknamed "wobble") when the clutch is disengaged.
You agree on that part.

When the clutch is engaged, that RUNOUT position is locked in place by the plates.
A random position. The heavy clutch assembly, significantly off center shakes like a whore in church. I've observed it. I can feel it through the footpegs. I regularly "adjust it" while underway to try and get a slightly better chance/random position.

So, the clutch basket bearing ABSOLUTELY affects the clutch runout while engaged.

Best to keep the runout as small as possible. Because it is there while underway, beating up the sleeve gear bushes, and the sleeve gear bearing.

There is slop in the plates, there is an unbalanced basket, there is an unbalanced center, there is a (probably) not perfectly straight main shaft, the other end of the mainshaft is held in place by a bearing with clearance, there is slop in the center to main shaft splines, as the clutch engages there is great force being applied by the chain, the clutch is position by a stupid circlip, and you think a few microns difference in the clearance of the clutch bearing is a big deal.

I don't.

concours · Nov 24, 2023

marshg246 said:
There is slop in the plates, there is an unbalanced basket, there is an unbalanced center, there is a (probably) not perfectly straight main shaft, the other end of the mainshaft is held in place by a bearing with clearance, there is slop in the center to main shaft splines, as the clutch engages there is great force being applied by the chain, the clutch is position by a stupid circlip, and you think a few microns difference in the clearance of the clutch bearing is a big deal.

I don't.

Wow.
Where to start...

marshg246 · Nov 24, 2023

concours said:
That clutch basket/sprocket, bunch of steel plates, pressure plate, diaphragm spring all orbiting about, known as runout, (nicknamed "wobble") when the clutch is disengaged.

Just because you have me in a contrary mindset - runout and wobble are not the same thing in this context.

If you think of truing a wheel, the runout is the "hop" or changing distance from center. Wobble is the uneven side-to-side deviation and is normally worked on after the runout is removed.

If the clutch basket forward edge to crankshaft distance is changing, you have runout. If the clutch basket is wobbling (they absolutely do) when disengaged that can and usually does happen with no noticeable runout. If you have runout, with the clutch engaged or not, you have something to fix, not a bearing clearance issue. If you have wobble with the clutch engaged, you have something to fix, not a bearing clearance issue. If you have wobble with the clutch disengaged, unless extreme - things are normal.

Tripler · Nov 24, 2023

Wow a simple question certainly grew into a great debate

Yakatak · Nov 24, 2023

I like a good debate. For the most part on this forum, debates remain reasonably civil and are usually very informative.

concours · Nov 24, 2023

marshg246 said:
Just because you have me in a contrary mindset - runout and wobble are not the same thing in this context.

If you think of truing a wheel, the runout is the "hop" or changing distance from center. Wobble is the uneven side-to-side deviation and is normally worked on after the runout is removed.

If the clutch basket forward edge to crankshaft distance is changing, you have runout. If the clutch basket is wobbling (they absolutely do) when disengaged that can and usually does happen with no noticeable runout. If you have runout, with the clutch engaged or not, you have something to fix, not a bearing clearance issue. If you have wobble with the clutch engaged, you have something to fix, not a bearing clearance issue. If you have wobble with the clutch disengaged, unless extreme - things are normal.

You're using slang, to define axial, and radial runout.

Both axi have runout.

The phenomenon I describe has been witnessed by myself in motorcycle, truck & car clutches.
Failed input shaft bearings exhibit the same symptoms.

Please, don't respond as if this is a personal, thing. It's not.
Nuts & bolts only.

marshg246 · Nov 24, 2023

concours said:
You're using slang, to define axial, and radial runout.

Both axi have runout.

The phenomenon I describe has been witnessed by myself in motorcycle, truck & car clutches.
Failed input shaft bearings exhibit the same symptoms.

Please, don't respond as if this is a personal, thing. It's not.
Nuts & bolts only.

I didn't start the thread. I didn't use wobble first.

Tired of this.

IMHO any modern C2/CN/C3 6007 bearing will do the job and I will continue to use quality CN clearance bearings for the purpose. Clearly you are the expert even without providing a single number to back you up - I'm out.

Clutch hub bearing

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