Gearbox Bearing

[PhilMill63]

Hi All, I've pulled off the outer gearbox cover behind front sprocket and I've found the gearbox bearing behind the sprocket is knackered, glad I ended up pulling it apart rather than riding it. Anyway, I found a part number 92045-021, but other then CSNL I'm struggling to find a replacement, and CSNL want 187eu which seems crazy for a bearing. Any suggestions where to source this? I'm guessing its a relatively normal bearing other than the grove for the retainer?

Phil

[z2.john]

You must get a C3 fit if you find an alternative. This is slightly looser tolerance to allow for heating up from cold to hot engine

[Skid Mark]

You must get a C3 fit if you find an alternative. This is slightly looser tolerance to allow for heating up from cold to hot engine

would you mind expanding on this please John?

[z2.john]

You must get a C3 fit if you find an alternative. This is slightly looser tolerance to allow for heating up from cold to hot engine

would you mind expanding on this please John?

To quote from a bearing manufacturer:..............

"Internal clearance being C3 means that the bearing has room for expansion if needed between the races of the bearing, whilst holding the outer ring and moving the inner ring in a radial movement you will detect a little amount of play between the two rings. All standard clearance bearings have this movement, it may only be a small amount of movement but is controlled by international standards. C3 means the bearing has more clearance than standard.


For example we may use C3 clearance on bearings where a cold start up application may cause the balls to heat up quickly, the heat needs to go somewhere. Some of the heat gets passed through the outer race to the housing and the inner race to the shaft, this causes expansion which closes up the clearance in the bearing. If you did not allow for this clearance the bearing would not have room for expansion and lead to bearing failure.


It is never advisable to replace a bearing with one having a lower initial clearance. By the same argument, it is usually safe to substitute a larger clearance when the desired clearance is not available."

[chrisu]

https://www.z-power.co.uk/z900a4-kz900b1-ltd-1975/bearing-output-shaft

not cheap

[Skid Mark]

You must get a C3 fit if you find an alternative. This is slightly looser tolerance to allow for heating up from cold to hot engine

would you mind expanding on this please John?

To quote from a bearing manufacturer:..............

"Internal clearance being C3 means that the bearing has room for expansion if needed between the races of the bearing, whilst holding the outer ring and moving the inner ring in a radial movement you will detect a little amount of play between the two rings. All standard clearance bearings have this movement, it may only be a small amount of movement but is controlled by international standards. C3 means the bearing has more clearance than standard.


For example we may use C3 clearance on bearings where a cold start up application may cause the balls to heat up quickly, the heat needs to go somewhere. Some of the heat gets passed through the outer race to the housing and the inner race to the shaft, this causes expansion which closes up the clearance in the bearing. If you did not allow for this clearance the bearing would not have room for expansion and lead to bearing failure.


It is never advisable to replace a bearing with one having a lower initial clearance. By the same argument, it is usually safe to substitute a larger clearance when the desired clearance is not available."

Another wrinkle in my arse!

[Mr Bump]

I may have a good used one if you want it. I'll have a look this evening if you like.

Olly

[Z1streetfighter71]

The full bearing set is £195 its worth the few extra pounds to be sound in the knowledge that whole area is sorted.

[PhilMill63]

Thanks all, a whole new set sorted thanks to the great members of this club.

Phil