Author Topic: Bearing recomendations for gearbox/clutch  (Read 1637 times)

Offline GuyboA10

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Bearing recomendations for gearbox/clutch
« on: 23.05. 2008 13:15 »
G'day, just curious about the appropriate bearings for the mainshaft/clutch end (24-4065)and kickstart end(24-4217). Both were hoffman open types which were removed. Should i stick to the open style, or go the 2RS ( rubber shields) ??. I reckon there is always a chance dirt & metal fragments can affect the open type, so i feel the 2rs is more suitable, is this ok? Also, should i get both bearings with CN ( clearence normal)? I know some people have used C3 bearings on different parts.
The driveside main roller bearing is a hoffman r130 v3 and the replacement is NF206. Does this come in CN & C3? and which one is correct? i'm thinking CN.
cheers, Guy.
ps. my resto is going well, everything is apart and is being cleaned up, polished , de-rusted etc... found i've got near new pistons and nicely polished conrods, also the cylinders look newly bored..beautiful looking!!!  *smile*Step by step and slowly it will be a great bike when finished, cant wait!! But its great fun building it up. cheers..

Offline dpaddock

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Re: Bearing recomendations for gearbox/clutch
« Reply #1 on: 24.05. 2008 23:11 »
I'd stay with the open bearings and BSA oil recommendations. Drain the oil at intervals based on how much debris you find (can't be much unless you're having a problem - in which case, you're in early innings). It's not always wise to re-engineer the designers' decisions. A magnetic drain plug would be a good thing.
David
'57 Spitfire


Online Brian

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Re: Bearing recomendations for gearbox/clutch
« Reply #2 on: 25.05. 2008 02:45 »
What I do is remove the seals from both sides of the kickstart end bearing but on the drive end I only remove the inner seal. When I put the final drive sprocket on I put some grease between this seal and the proper one. This effectively gives you a double seal. I have been doing this for many years and have bikes that have done many thousands of miles and it has worked perfectly. With the bearing clearance I use SFK Explorer series bearings which are a finer tolerance bearing but unfortunately I dont know exactly how they are rated, a bearing company should be able to say. Once again I have had no problems with them. Good luck with your rebuild.  Brian.

Offline Rocket Racer

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Re: Bearing recomendations for gearbox/clutch
« Reply #3 on: 16.03. 2016 04:55 »
Having rebushed layshaft and sleeve gears, I was in the process of replacing the  SC  gearbox bearings and was quite surprised to find the old Hoffmann that came off the layshaft was a C3 clearance bearing.
The question is should I fit another  C3...  *conf*
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
New Zealand

Offline duTch

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Re: Bearing recomendations for gearbox/clutch
« Reply #4 on: 18.03. 2016 10:23 »

 I had an issue like that when I replaced my Gutzzi driveshaft bearing at the uni-joint. Can't remember all details, but I think I was inadvertently given a C2 (?) from the bearing shop.
 When it heated up, th bearing tightened up more than the interference fit factor, and the bearing spun on the uni-joint and flogged it (x2or3) out leaving me with an unnerving vibration, so 'C' factor depends on careful assessment of the application. *pull hair out*
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online chaterlea25

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Re: Bearing recomendations for gearbox/clutch
« Reply #5 on: 18.03. 2016 20:35 »
Hi
C3 for the crank and gearbox main bearings

John
1961 Super Rocket
1963 RGS (ongoing)

Online Brian

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Re: Bearing recomendations for gearbox/clutch
« Reply #6 on: 18.03. 2016 21:27 »
Just for a bit of info for those not familiar with bearings I thought a small explanation of bearing clearances might help.

C2  -  slightly less clearance than standard
CN  -  standard or normal clearance
C3  -  slightly more clearance than a CN
C4  -  slightly more clearance than a C3
C5  -  slightly more clearance than a C4

I tried to find a chart online that would give some figures in thou's but couldnt.

Dutch, I always fit C4's in Guzzi's.
In my BSA's I use CN in all applications.

The bearing that carries the uni joint in a Guzzi is a tight fit in a steel housing and have quite a lot of "crush" when fitted. The bearings in the BSA's have virtually no "crush" effect.

Offline duTch

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Re: Bearing recomendations for gearbox/clutch
« Reply #7 on: 18.03. 2016 21:51 »

 
Quote
The bearing that carries the uni joint in a Guzzi is a tight fit in a steel housing and have quite a lot of "crush" when fitted.

 Thanks Brian, I think we worked out that was what was happening- took a couple of U.J's though
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia