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lostandwandering
10-22-2007, 05:56 PM
I appologizie if this has been covered but I couldn't find a reference.
While doing a spline lube of my 87, K75S I noticed the universal joint has a definite flat spot (Kind of like steering head bearings when they've developed a notch in the race). I know if this was a drive shaft on car it'd need to be replaced but I'm not sure with the bike. Clymer only mentions that they should be replaced if there is noticeable side play (there isn't). Can anyone tell me if this is a problem? Is the universal replaceable or does the whole shaft have to be replaced if it is a problem?
Thanks for your help.
PGlaves
10-22-2007, 07:26 PM
The flat spot, sticky spot, clicky spot - is the first sign of wear. Shortly you will get that looseness and play. Maybe next week. Maybe 20K miles.

I personally replace them when they get that way - usually after about 80K or 100K miles or so. I do that because I don't want it grenading while I'm going down the road. First of all - it ruins the trip. And secondly, if it comes apart it is possible for the driveshaft to lock up in the swingarm. That can lock up the rear wheel. An interesting control problem going down the highway at speed. I have seen one case where it also fractured the swingarm casting.
mrich12000
10-22-2007, 09:15 PM
Hay "P" so do you have a replacment joint, and the procedure to do the repalcement. please share.

Drive Shaft on A&S BMW Motorcycle Parts and Accessories
http://search.ascycles.com/motorcycle/Drive%20Shaft

:clap :clap :wave Mike Rich
PGlaves
10-23-2007, 12:40 AM
Hay "P" so do you have a replacment joint, and the procedure to do the repalcement. please share.

Drive Shaft on A&S BMW Motorcycle Parts and Accessories
http://search.ascycles.com/motorcycle/Drive%20Shaft

:clap :clap :wave Mike Rich

I didn't mean to imply a replacement joint. It can be done by a good machinist with the right part, I'm pretty sure - but I've always replaced the shaft. The reason is that the rear splines wear on those shafts. Usually by the time the universal joint is bad, so is the spline.

There are places that rebuild the splines - and probably can rebuild the U joint too.
lostandwandering
10-23-2007, 06:02 AM
Thanks Paul,
Interesting this bike has 11,000 not 110,000 miles so it has been idle most of its life, the reason for the current spline lube and I can assume the reason for the flat spot.
Thanks for the link to A&S Mike, I'm hoping for the $137 shaft as opposed to the $600 one.
Larry