560XP Crank Bearings

[Macpherson]

Oh well , just a thought

[wrsni]

I've never ever seen a plastic cage fail on it's own.

 

If the bearing fails first obviously that'll destroy the cage but you can't deduct that the cage failure happened first when there is no evidence or reason to support it.

[njm]

I've never ever seen a plastic cage fail on it's own.

 

If the bearing fails first obviously that'll destroy the cage but you can't deduct that the cage failure happened first when there is no evidence or reason to support it.

 

Yes you can when you have a bearing with no cage ! bearings are all still intact minus the plastic cage ,

[wrsni]

That's really odd. If the bearing is still intact then there's no load at all on the cage and it's hard to see what would annoy it.

 

Is the bearing fitted with the cage on the crank side or the seal side. I always fit them with it on the seal side so it doesn't obstruct the flow of mixture around the bearing but I doubt it should matter that much anyway.

 

Just a thought.

[njm]

That's really odd. If the bearing is still intact then there's no load at all on the cage and it's hard to see what would annoy it.

 

Is the bearing fitted with the cage on the crank side or the seal side. I always fit them with it on the seal side so it doesn't obstruct the flow of mixture around the bearing but I doubt it should matter that much anyway.

 

Just a thought.

Bearings can only be fitted one way , extension on one side for the crank seal

[Macpherson]

I've never ever seen a plastic cage fail on it's own.

 

If the bearing fails first obviously that'll destroy the cage but you can't deduct that the cage failure happened first when there is no evidence or reason to support it.

 

I take your point, in many failures there`s no way of telling what happened first but over my time i`ve replaced many bearings due to the state of the cage even

when there was no apparent excessive play, not just plastic but bronze and steel also, particularly in a crankshaft situation the cage gets it where a ballrace has been used to control endfloat for instance. cheers

[wrsni]

I take your point, in many failures there`s no way of telling what happened first but over my time i`ve replaced many bearings due to the state of the cage even

when there was no apparent excessive play, not just plastic but bronze and steel also, particularly in a crankshaft situation the cage gets it where a ballrace has been used to control endfloat for instance. cheers

 

A ball bearing can't withstand any degree of lateral load.

 

If there's any appreciable degree of end float it should be shimmed up unless the crank can move through the inner race of the bearing. But if there's lateral load on the crank and it's being transmitted through to a ball type main bearing then it'll fail prematurely.

 

In such a case the main bearing should be a roller.

[peatff]

Plastic cages are specified in a lot of applications nowadays with the plastic able to absorb lubricant to preserve the bearings. This is part of the specification, I had it explained to me at great length when I asked specifically for some metal caged ones at the local bearing supplier. The cage is only there to position the bearings in the race and with the advances in plastic technology they can withstand much higher temperatures.

[Stubby]

I remember in my push bike youth when the cage failed in the crack bearing you just cleaned out all the swarf and debris , put some new grease in and just added one extra ball . Shazam !

[adw]

I feel there is nothing wrong with the bearing, the cage is there to keep the balls apart, if the cage breaks up it is because it was the way it was fitted ie stressed and loaded up, when you rebuild and engine and do the final tighting of the crankcase screws you need to give a tap on either side of the crank ( copper hammer ) to releave any side loading.