Author Topic: Crank shaft Bearing options  (Read 537 times)

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Offline [Mossi398]

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Re: Crank shaft Bearing options
« Reply #15 on: February 14, 2020, 09:46:31 AM »
If one goes down the vitron 1.6mm seal route with all four crank shaft bearings being NR type with groove, what do you do with the labyrinth seal? Umm !!!
 

Offline G Jones

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Re: Crank shaft Bearing options
« Reply #16 on: February 14, 2020, 10:33:15 AM »
If one goes down the vitron 1.6mm seal route with all four crank shaft bearings being NR type with groove, what do you do with the labyrinth seal? Umm !!!
This...

Offline 5port

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Re: Crank shaft Bearing options
« Reply #17 on: February 14, 2020, 05:24:03 PM »
Hi Gordon.  Those pics look worryingly like the pattern lab seals without the cut-outs in the outer (side) faces, that can stop the oil feeding the main bearings?  :-\

5port
5port

Offline G Jones

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Re: Crank shaft Bearing options
« Reply #18 on: February 14, 2020, 08:15:15 PM »
Hi Gordon.  Those pics look worryingly like the pattern lab seals without the cut-outs in the outer (side) faces, that can stop the oil feeding the main bearings?  :-\

5port
I can assure you these are not the seals that caused you (and me) so much trouble - I have these made for the TZ - and superb tolerances give us no trouble - I also have a way to use on the RD too - but that's another story...

Offline [Mossi398]

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Re: Crank shaft Bearing options
« Reply #19 on: February 15, 2020, 01:43:15 AM »
Thanks for the picture, nice solution would be interested to know the other story for use on RD if possible.
 

Offline 350GUY

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Re: Crank shaft Bearing options
« Reply #20 on: February 15, 2020, 04:12:01 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.

Thank you Sir for your very detailed explanation, now things are much clear. For some reason, them 2-stroke Polaris Ski-doo & Rotax crankshaft main bearings are C4 rated. So I guess those bearings are used on their cranks since they generate more heat and rev at higher RPM's? In fact I was planning to use the two 6206 C4 bearings for the center that I have on the crank I plan on recondition. For the outer bearings, I do have a pair of OEM HIC (6305N) . So I guess this combination wouldn't be recommended? Thank you for your time, much appreciated.