kz650-d4 16" with kz550-b2 rear wheel swap, help!

Hello everyone, I'm always reading and learning lots of stuff from you guys. Today I need some help on swaping my 1981 kz650sr d4 16" rear wheel with a kz550b (b2 1981?) 18".

The things is that I'm in Argentina and it's a pita to import used parts, so we must to take advantage of local used parts when are available. A forum friend offers me an 18" rear wheel from a kz550 and the only data that I have is some pictures he sent to me. Doing a research with the frame number he sent me and looking at "Model_Recognition_1979-1981.pdf" I can establish that the kz550 is a B2 model but I can't find the rim part number.

According to partzilla 1981 KZ550-D1 the rim (41073-1140-21) and axle (41068-1086) could be used in kz550/kz650/kz750
rim
www.partzilla.com/parts/detail/kawasaki/KP-41073-1140-21.html
axle
www.partzilla.com/parts/detail/kawasaki/KP-41068-1086.html

It could be posible to do a direct swap (using caliper and rotor from my bike) with the rim that tehy are offerong me? What about the tyre size?

Any help would be appreciated. Cheers, Charlie.

Some pictures to clarify the things.

That wheel will fit your 17mm axle but the disk from your 650 will not bolt on to the 550 wheel. The 550 disk has 7 bolts the SR disk has 4. I would see if he would give you the disk, caliper, and master cylinder from the 550 as well. You will likely need to make spacers to center the 550 wheel.

also if you get the 550 disk make sure you get the mounting bolts. they would be hard to find elsewhere.

DoctoRot thank you for your input. Looking at the parts catalog of my D4 model, I can see that the rotor has 7 bolts as the one on the kz550 rear wheel, Googled the rotor part number 41080-1031 (41080-1131) and I found at Partzilla that the list compatbilty ítems includes kz750 and the kz550 (D1 from 1981).

www.partzilla.com/parts/detail/kawasaki/KP-41080-1131.html

The D4 was not sold in US is quite difficult to find information. Your valuable comments made me look for better compatibility, having the same rotor I feel more close to do the transaction.

Cheers, Charlie.

Interesting, i thought the D4 was actually a typo because i couldn't find it listed as a model. Looking at the picture of your SR closer i can see you do have the same front wheel/rotor as the 750. So i think you are correct in thinking your rotor will fit the 550 wheel. Good luck with your swap.

Thank you DoctRot... when I finish with this I'll post some pictures. Cheers, Charlie

Swap is done. It was a direct one. Changed bearings and tyres (also front tyre to match the rear one, Metzeler Lasertec)

Very nice. looks much better than the 16"