New Timken Clutch bearing - excess play

When I was doing my Alton estart work a while back I noticed that there was a bit of play (wobble) in the clutch bearing so I decided to get a new bearing and a new timing chain (and, what the heck - new Barnett steels and friction discs). AFAIK, the original bearing/chain were in the bike. Today I removed the old FAG Bearing and installed the new AN Timken bearing. The new Timkin bearing has more play than the old FAG and "rumbles" when spinning. Clearly the races and/or balls are brinelled or otherwise not as precisely machined as Timken bearings used to be. At first I was pleased to see "Timken" on the bearing when I removed it from the AN plastic bag but that lasted only until I installed it and discovered the greater play and the roughness.

So I removed the new AN Timken and put the old FAG back in - a waste of 25 bucks. Barnett still seems to know how to make clutch plates/steels!

Send the Timken back to AN and request a replacement and an inquiry as the apparent condition. Its important for AN and us to know these thing can happen and if it actually was out of spec.

Hello all

This Timken bearing supplied by AN.

I find it hard to believe there is manufacturing defects but I suppose it would happen now and again. A small bearing such as this in unmolested packaging would have to be severly handled and subject to a lot of vibration in transit to have brinelled before use. I have seen a bit of this in large bearings not prepared for transportation and sent thousands of miles on a semi over shocking roads.. In this case unlikely.

As for rumbling if not supplied in makers packaging, dirt, or contaminents may very likely ingressed inside.

Was the bearing sealed in a plastic packet and this packed in a small cardboard box as supplied by the bearing maker. This is to determine if it was delivered sealed and UNOPENED as the maker intended. These are garden variety bearings, surely u could get this from bearing supplier locally. Unmolested makers packaging of course.

Also I must repectfully ask if in fitting any damage was done or dropped on floor etc. for instance fitting by driving on inner race WILL damage bearing causing rumble. Brass punches are also a no no. Damage in fitting is very easy to do and must be regarded as a more likely cause than manufacturing defects.

Very keen to hear the full story.

Bradley

Hello again

forgot to mention. what clearence class was the bearing. Normal, C3, C2 . Are you replacing like with like. The differnce between normal and C3 is probably only 10 or 15 microns(metric) and would be very hard to discern. without actually measuring clearences accuratly , any claim regarding clearance is very subjective unless the bearing is completly worn out..

As for Andover Norton, the quality of parts has been such as to deter me from going anywhere else and the responses by Nick Hopkins have been outstanding in helpfulness. Other peoples opinion may differ.

Bradley

According to the factory manual it is supposed to be a tighter than standard clearance "one dot" bearing.

Hello all

Yes Mr LAB, you are correct. I had not brought this up because i assumed the bearing supplied complied to makers (norton) specifications. The weight of the clutch and applied forces may very well require a closer clearence. That isn why it is important that like is compared to like.

The whole point of my post is that if the bearing is correct specifications, and comes from a reputable manufacturer, it is more likely that incorrect fitting technique has damaged the bearing than a poorly made bearing was supplied.

here comes the howls of disagreement regarding the so called infamous Portguese lay shaft bearing.

I really doubt that a reputable bearing manufacturers quality control allows non confirming bearings to be marketed.

i still await more information being supplied by Mike.
Bradley

The bearing was sealed in the AN plastic bag with cardboard part number enclosed and the bearing was seperately wrapped in a sealed wrapper.

It was installed correctly - with the appropriate spacers/press. The old Fag bearing, after being removed and reinstalled is smooth and has less play. I can't make any other judgments re whether this was one bad bearing...I personally doubt that but I guess it is possible.

Hello Mike

Well Mike, this one is a bit of mystery to me then. Logically, if bearing un opened, and fitted correctly and no contamination the obvious is a bad bearing. I still have reservations about this but will concede u r correct.
Bradley

B.Rad said:

Yes Mr LAB, you are correct. I had not brought this up because i assumed the bearing supplied complied to makers (norton) specifications. The weight of the clutch and applied forces may very well require a closer clearence. That isn why it is important that like is compared to like.

Click to expand...

There seems to be a certain amount of confusion about what the correct current specification is regarding the clutch bearing clearance.

I did ask ZFD (Joe Seifert) for clarification of exactly which clearance bearing AN supplies, however I don't recall the question ever being answered.

clutch-bearing-clutch-centre-fit-t12490-15.html#p147730

"I still have reservations about this but will concede u r correct."

I don't know what other conclusion to come to other than bad bearing. I install a lot of bearings in all sorts of things from small elec motors to Detroit Diesel V71 engines/Allison transmissions. I had a similar problem recently with a new pair of bearings for a vintage Ampex studio tape machine motor that I was restoring. The new bearings (Chinese) made the motor so noisy the machine was unusable. A second pair of bearings obtained from NOS (New Departure from the 60's) were fine/quiet.

I used the appropriate sleeves for installation of the clutch bearing; at no time was there any pressure on the inner race/ball surface area. It seems as if perhaps one ball is bad. With the cultch basket in place and some ATF to lube the bearing, if I spun the basket it would spin quietly for many revs and then suddenly give a slight "rumble" then go back to smoothly spinning. So it sounds like perhaps one ball has a rough spot or tiny flat on it or something like that. If it was the race that was the problem, it would rumble as each ball got to that spot which would cause an essentially constant rumble.

I was awake half the night thinking about this. I'm going to try to examine the bearing with a 10x loup to see if I can see anything useful. I doubt I will be able to see much of the balls/race with the cage in there but maybe. I'll also thoroughly flush the bearing with solvent and then hot soapy water followed by compressed air and oil and see if it smooths out at all. Even if it does, it still has more "wobble" than the original bearing.

That bearing question- I thought I answered it at the time, I remember speaking with Nick Hopkins about it. Will come back on it.
Joe

I just read that thread referred to - I had not seen it prior and it is clear that the clutch bearing was already much discussed - at least re the play (wobble). If I'm reading/understanding that thread, the currently supplied bearing has more play than the bearing originally specified for that purpose. If so, that certainly could explain why an old bearing, despite normal wear, has less play than the new bearing.

A 6007 bearing with standard clearance will have about 5 µm more radial play than a "tight" one . ( that's .0002") , nothing you can notice without measuring.
Not saying it's not important , but if you can feel a bearing play , it's toasted , not manufactured within tolerances.

Ignoring the roughness issue...

With the new bearing installed in the clutch basket and the basket bolted to the gearbox shaft, there is .025" of play wobble) at the outer edge of the clutch basket measured with a dial indicator. Seems like an awful lot of movement. The old bearing produces .020". So clearly the Fag bearing that was in there for who knows how long, had a tighter tolerance originally than the current Timken. In any case, I'm done swapping bearings back and forth to make measurements.

The Fag bearing is readily available but maybe the current Fag is exactly the same as the Timken. I guess the only way to find out is to buy one of each and check them.

Have you also measured the main shaft sleeve bush wobble to subtract from the bearing wobble amount? To feel for brinnelling one needs to slowly dry roll and roll many rounds till damage areas line up to be felt. If bearing really questionable definitely alert maker to see what's up. They might even pay ya as less expensive to discover quality issue early than lawsuits from damage that hurts people as well as machines.

"Have you also measured the main shaft sleeve bush wobble to subtract from the bearing wobble amount?"

Yes, the wobble measurements were of the play within the bearings themselves. I locked the center section/shaft rearward with a bar clamp to ensure that there was no play between the center and shaft and between the shaft and bushing.

Ok you compensated then, but would be educational to see what main shaft itself is doing I've gotten clutches to have undetectable wobble by feel, though it don't last perfect for long but stays adequate a good while like years of sane use. Await you final install decision.

I put it back together with the original Fag bearing since it has less play than the new Timken. I ordered a new Fag bearing to see if there is any difference between it and the AN-supplied Timken re internal play (and the roughness). I didn't think to check the actual play in the tranny shaft but I'll do that when I go back in to try the new Fag. I'm getting really fast at disassembling the chain case parts! The Alton Estart does add a bit to the complexity of doing that but it's just a few extra fittings to deal with - probably doesn't add 5 minutes to the process.

This added later: I ordered a FAG 6007 Radial Bearing, Single Row, ABEC 1 Precision, Open, Steel Cage, Normal Clearance.

I had sent a message to Old Britts re the bearing, enquiring if Fred had any personal specs/preferences re the bearing play but he did not. Perhaps I'm making something out of nothing re that wobble. It just seems "wrong" to me. But as an experienced Norton rider/mechanic told me re the bearing play last night over several glasses of wine, "It's a Norton, it doesn't matter!"

But I'm still going to install the new Fag bearing when I get it and see if there is any difference in the play. I'll post what I find.