Z1OwnersClub GB

Hello, I'm restoring a Z1000 engine and the bearing behind the output sprocket has two cut outs in the bearing races. What function do these cut outs perform and are they necessary as the genuine replacement bearings are over £100 each and a similar bearing without the cut outs is about £20?

Cheers, MikeJ

the groove is locate the bearing in the crank cases & there is a half moon shaped ring that prevents the bearing from moving sideways. dont use a standard bearing

Welcome to the wonderful world of restoration.

Hello,

thanks for the replies but I'm not talking about the peripheral circlip groove, rather the cut outs in the races adjacent to the bearing balls. I'm thinking that they may be there to pump oil away from the oil seal, but they seem to be on the wrong side for that and there's a spacer between the bearing and the adjacent gear so I don't think they are to lubricate the gear, maybe to lubricate the bearing itself? The bearing I've found has the circlip groove so that's not a problem,

Cheers, MikeJ

The cut outs allow more balls to be fitted into the bearing , a high load bearing . A normal bearing with circlip grooves will not have the same load capacity as the standard bearing . If you fit a normal bearing it will collapse under the load and you will have to strip the motor again . Do the job once and do it right .
fer

As Fer says.
The reliefs in the outer race were to allow insertion of the ball bearings on initial assembly.
You need to replace the bearing with one of the same load rating to avoid premature failure.
The original bearings do last a very long time under normal circumstances though so unless damaged or corroded may not need replacement just for the sake of it.

NSK BL305n is the bearing you want . I think TZ cranks use them .
fer

Many thanks for all the replies- I've ordered one of the HD bearings,

Cheers, MikeJ

chrisw1 wrote:https://www.amazon.co.uk/NSK-BL305-NRC3NSK-Radial-Bearing/dp/B076TG3PPS

looking at this bearing i dont think the groove in the bearing is is the same width as the genuine kawasaki bearing & the retainer is much thinner than the groove in the crank cases ?