Is theis sprocket carrier bearing pooped?
 

Hi all, ive tried to get to the bottom of the clicking and grinding noise coming from my rear wheel... Is it this?
There seems to be a groove knawed out from the Inner ring of the bearing. Or is it 2 bearings butting up to each other?

Thanks
Paolo

Paolo,
I haven't looked at a 750 one recently, but the one on a 620 cushdrive is the same. If nobody gets back to you I'll have a look at a 900 ione tonight.

Cheers, Paul

PS are you sure that the noise is not caused by a worn sprocket or streched chain?

well, it sounds a bit clunky when I wheel it out of the garage... it could be the chain and spookers, tho. When I took the wheel off I nothiced the chain was like it was made out of cardboard...

Paul

suppose the best way to check now is to re-fit the rear wheel and run down the road with it without the chain...

Try spinning the bearing by hand before you put it back together. It should spin freely with no roughness and only a slight swishing sound. If you hold the bearing by the inner track you shouldn't be able to rock the outer from side to side. If it is tight, makes graunchy noises and/or you can wobble the outer about it needs replacing. The bearing code will be stamped on one side of the outer track and you should be able to get one from any reasonable motor factor or bearing specialist - look in the Yellow Pages.

ive found that the bearing IS knackered, its rougher than the wheel bearings and is quite crunchy! is it 2 bearings? or just one biggie?

There are 2 bearings side by side. Even if only one is showing signs of wear you are best to replace both because the other won't be far behind it.

OK, cheers derek... does anyone have the measurements for the bearing?

okay, I have the part number for it...
70250451a
or got to a bearing shop and ask for 6005 double seal (2 of)

Try and take the bearings to a motor factor or bearing specialist, I took mine in pieces and it didnt matter, they were still able to source the correct item for me.

electronic yellow pages is useful here:

http://www.yell.com