Author Topic: Crank shaft Bearing options  (Read 612 times)

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Offline [Mossi398]

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Crank shaft Bearing options
« on: February 08, 2020, 05:00:32 AM »
Hi just wondering, has anyone used crank shaft bearings other than Koyo. I know they have pips to stop spinning but can NSK or FAG for example be used with out pips & use some loctite product. Regards Phelim.
 

Offline D Peacock

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Re: Crank shaft Bearing options
« Reply #1 on: February 08, 2020, 08:21:40 AM »
Yep, I use pegless bearings and glue the crank in place with Loctite bearing fit. Let’s just say they won’t spin....
For speed add lightness!

GSXR1100 - Away for engine rebuild
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Offline [Mossi398]

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Re: Crank shaft Bearing options
« Reply #2 on: February 08, 2020, 09:40:49 AM »
Good news.Thanks.
 

Offline doggone1

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Re: Crank shaft Bearing options
« Reply #3 on: February 08, 2020, 10:07:29 AM »
I was going to fit mine with o ring cord 1.6 mm I think I haven’t got around to doing it yet but there is a thread on here somewhere with details I think

Offline doggone1

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Re: Crank shaft Bearing options
« Reply #4 on: February 08, 2020, 10:08:54 AM »
Get my koyo bearings from George lodge find them very reasonable

Offline [Mossi398]

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Re: Crank shaft Bearing options
« Reply #5 on: February 08, 2020, 01:32:10 PM »
Hi doggone 1, did you mean Viton seals you make yourself? That would also work. Ive got 5 crank shafts that need rebuilding , rebuilt a crank shaft a few years ago with Koyo bearings so just looking at options to keep costs down some what.
 

Offline vannerman

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Re: Crank shaft Bearing options
« Reply #6 on: February 08, 2020, 04:00:35 PM »
I bought SKF 6206 NR explorer  and SKF 6305  NR explorer bearings which come complete with a snap ring, which you remove and replace with a 58mmx2mm viton o ring ,I think that is the set up used by HV cycles in america.By the way I can not say how good they would have been as in the end I had the crank rebuilt by Grampian 
Dave

Offline AndyDean42

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Re: Crank shaft Bearing options
« Reply #7 on: February 08, 2020, 07:13:12 PM »
Any brand should be OK, but remember you need a C3 grade bearing. It has a different radial clearance to standard bearings.

Andy
RD400C, RD350B (new project), GS750E

Offline doggone1

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Re: Crank shaft Bearing options
« Reply #8 on: February 08, 2020, 07:18:19 PM »
Yes thats what ive been told to use the seals you make yourself as they are not available in the correct size ive got to do mine soon so will be better placed to comment once its done i think its important to do a dry assembly to make sure everything goes together correctly

Offline doggone1

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Re: Crank shaft Bearing options
« Reply #9 on: February 08, 2020, 07:20:27 PM »
I was told 1.6 mm but this is not first hand knowledge so I will try that and 2mm as mentioned above and see what is best I think it seems to be a common use in the states instead of pips at least they wont groove the cases if they did spin
« Last Edit: February 08, 2020, 07:22:05 PM by doggone1 »

Offline [Mossi398]

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Re: Crank shaft Bearing options
« Reply #10 on: February 09, 2020, 01:25:51 AM »
AAH I see so basically all four bearings need to be NR bearings,6305NRC3 & 6306NRC3 with groove/ snap ring for seal .Thanks guys.
 

Offline 350GUY

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Re: Crank shaft Bearing options
« Reply #11 on: February 13, 2020, 05:43:32 PM »
Any brand should be OK, but remember you need a C3 grade bearing. It has a different radial clearance to standard bearings.

Andy

Howdy Andy! are C4 rated bearings considered superior or an upgrade over C3 for the RD350 crank? I have a pair and I am hesitant to use them.

Offline doggone1

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Re: Crank shaft Bearing options
« Reply #12 on: February 13, 2020, 06:47:27 PM »
C4 are looser than C3 so I would stick with the C3 thats specified for sure.
C3, C4 and C5 bearings are bearings that have an additional internal radial clearance to cope with high speed environments where excess heat is generated. They are not suited to environments where critical alignment is required from the onset e.g. Where blades and cutters are set up to each other. Applications like motorcycle wheels or bicycle wheels do not require C3 rated bearings. Unless the bearing you are replacing specifically says C3 on it then you should not replace it with a C3 bearing, C3 Bearings are loose to the feel from new and often people complain at the quality of the bearing being poor and having more movement than the one they are replacing. C4 and C5 are even looser still than C3 clearance bearings. This is the characteristic of these higher than normal clearance bearings marked C3, C4 and C5.

Offline 5port

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Re: Crank shaft Bearing options
« Reply #13 on: February 13, 2020, 08:59:34 PM »
Applications like motorcycle wheels or bicycle wheels do not require C3 rated bearings. Unless the bearing you are replacing specifically says C3 on it then you should not replace it with a C3 bearing, C3 Bearings are loose to the feel from new and often people complain at the quality of the bearing being poor and having more movement than the one they are replacing.

Some RD wheel bearings are specified C3, probably due to brake heating.

5port
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Online Bluehaze

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Re: Crank shaft Bearing options
« Reply #14 on: February 13, 2020, 10:55:50 PM »
Sometimes C3 bearings are specified for rebuilds, when the original ones had tighter clearance.
I noticed this in a repair manual for a USA made stationery engine.
No explanation was given. Perhaps a C3 is more forgiving of imperfect alignment control out in the field?