Driveshaft spring breaking
 

This summer, very shortly after replacing the motor on my '86 300 Bayou, I had the spring in the driveshaft break (#92081 in this pic). Kawasaki Klf300-a2 Bayou300 1987 United Kingdom As Drive Shaft/final Gear (lf300a-010034~) - schematic partsfiche .
Recently, my nephew changed the rear differential in my brother's '04 Bayou 250 and he had the same spring fail shortly afterwards.
Could there be something we did when we had them apart that caused this or is it just an unlucky coincidence? I'm asking because I'm getting ready to change my brother's drive shaft and want to make sure not to mess it up this time. I'm guessing it is a coincidence though since I've put several miles on the used driveshaft I replaced my broken one with.

I don't know about Kawasakis, but on many of the Hondas I work on, the shaft springs are broken. You don't usually know about it until you remove the shaft for some other reason.

Thanks. I'll make sure to check the spring on the one I'm going to put on my brother's then. I see they're still available online.