just another bearing question

I would like to put a spoke wheel on my 1980 kz750 ltd.I have one of a 78 kz 650.Now the question i have is can the bearings be switched out?You know put the 15mm bearings out of the oe wheel in the 650 wheel.Anyone know if the bearings are interchangable?Has anyone tried this?Thanks guys

You should get new bearings to install in your new wheel.
The bearings are usually sized by the inner diameter X outer diameter X width. They also carry a STD (ISO ?) number on them (like 6020, etc).
When you change the axle size you would need to replace the inner diameter of the bearing with your present size needed. For example, if you have a 15 X 40 X 12 bearing in the wheel now and you are putting it on a 17mm axle, you would need to get a 17 X 40 X 12 bearing. You would also need to get an inner bearing spacer (inside the wheel) with the correct axle diameter and length.
The same can be done with the outer diameter of the bearing (for example if you need a 42 mm outer diameter for your 17 mm axle it would be 17 X 42 X 12).
Sometimes when converting bearing sizes, you may run into the problem of the bearing not being available in the width you need (10mm instead of 12). This can be over come by making a outer spacer for the wheel (this example would use outer bearing spacers 2 mm longer on each side).
The measurements for the bearings are " for example" sizes and probably not what you would need for your conversion.
It's not that hard to do, just time consuming. Most bearing suppliers list the bearings in the sizes (inner X outer X width) mentioned above. They usually carry seals needed also.
Fish

Read the page linked for some good info on bearings:

www.gizmology.net/bearings.htm

Bearing are manufactured in standard sizes, and what you want is a non-standard bearing size. The bearing manufacturers will make a bearing specifically for you, but you don't want to know how much it costs.

Some people use inch size bearings to get close to what they need, but I'm not a fan of "close" when it comes to wheel bearings.

The usual way of swapping wheels is to make adapters (sleeves) to fit a smaller axle in a larger bearing. Sometimes you can have the bearing bore in the wheel enlarged or bushed (depending on which way you need to go) to fit the new bearings to it.

ok so i can get new replacement bearings off of ebay.im waiting for the guy to send me the measurements on them.The bearings look like they have the same outside diameter.We will see.

Here is a link to the bearing list in this websites Filebase. If your 750 is the H model (i'm not sure) they use the same bearings as the 78 650, 6203-2RS.

tinyurl.com/2gvlvp