Hi,
I'm attempting to restore a 1980 Z1R D3. I have now separated the cases but have found that the crankcase is damaged where the output shaft bearing sits. I knew that the bearing had failed at some stage but underestimated the amount of damage that had been caused. See photo.
My local engineering shop says that the only way he can fix it is to rebore the the opening for the output shaft a couple of millimeters larger and fit a larger bearing. He would then have to cut the groove for the bearing setting ring. I can source the larger bearing but it wouldn't have the groove for the setting ring which would then have to be machined into it. I'm not sure if he would be willing to undertake this. This bearing would also not be rated as highly as the one that has failed, which could be a concern.
Another option would be to source another set of crankcases, not an easy task given the rarity of the D3 model bikes.
So I have two questions:
1. Has anyone undertaken a crankcase repair of this nature and, if so, how was it done?
2. If I can't locate a set of D3 crankcases, what other ones would be suitable? I know that the later model J series are not compatible but what about late 1970s KZ models? There are a few on Ebay with engine numbers starting with KZT00AEnnnnnn. Would the D3 barrels, gearbox and crank slot straight in?