Here is a few more with out the rubber boots on the ends. See if those help. That u joint number is specific to brute force 650/750s rear drive shafts. I don't have one here at the shop or i would send some picts with measurements for you.

Rear drive shaft for a kawasaki brute force 750/650 IRS model. Will fit 2005-2014 IRS 650's or 750's. It is missing the middle seal,and engine side seal,redish color seal is the rear differential side and probably missing the internal spring. First link has a readable u joint for the number then other links are for sale links.

References:

https://www.ebay.com/itm/2006-Kawasaki-Brute-Force-650-IRS-4373-rear-drive-sh...

https://www.ebay.com/itm/2006-KAWASAKI-BRUTE-FORCE-KVF-650-REAR-DRIVESHAFT-DR...

https://www.ebay.com/itm/2005-2015-KAWASAKI-brute-force-650I-rear-drive-shaft...

https://www.ebay.com/itm/08-Kawasaki-Brute-Force-750-Rear-Drive-Shaft-Univers...

Reason:
Thank you for your opinion, but what we have has different ends from the links you attached. I tried to look around to compare each links but didn't find anything same to ours. Thanks again!

Here is a few more with out the rubber boots on the ends. See if those help. That u joint number is specific to brute force 650/750s rear drive shafts. I don't have one here at the shop or i would send some picts with measurements for you.

References:

https://www.ebay.com/itm/rear-drive-shaft-coupler-2005-kawasaki-brute-force-7...

https://www.ebay.com/itm/2005-KAWASAKI-BRUTE-FORCE-750-KVF-750-Rear-Drive-Sha...