As you probably figured out I do all my own work.I'm sure most guys here do too .I read and look closely at stuff as I take it apart and have a good understanding how stuff works.So today I pulled the rear wheel off to mount a new tire. No big deal,a simple straight forward job.I read the service manual about the torquing of the lugs and in there they were talking about a center bolt as well as the 4 lugs.I pull off the plastic hub cap and there is no center bolt.I look with a light and I see threads in there so I pull off the wheel to look .I see that there is a threaded part of the rear drive shown in the first photo here So I go out and buy a grade 8 bolt the right size and some grade 8 washers ,put the wheel back on and realize if I use the center bolt there is no way to install the hub cap .so my question is two parts, did the 1988 K100rs not have a center bolt or was there some sort of washer that had flats leaving enough space for the hub cap mounting tabs to fit into that large center hole in the rim ?

Well,I answered my own question by looking in a different book. There is no center bolt so it wasn't missing. now I can fit the new tire and move forward to the front wheel.

Is there a spacer washer between the rear wheel and the final drive?

Yes a thin washer that the 4 lugs go thru as pictured in the book

All you need now is good weather.

I think later series paralever rear end ..like on k100 16 valves and k1100 are the only ones with the centre bolt fitted

from what I have seen none of the "bevel" rear ends ...k100 x 8 valves had them fitted at all

just the washer- spacer between wheel and drive

the cover fits all similar models

obviously the cover off the later models has issues

hope that helps

I believe Charlie to be right. There's no point in machining no-thread wheels for one run of bikes and then threading them for another type - if the wheel is the same style on both bikes, it's far more economical to make them all the same on the production line.

When I fitted a 4.5x18 inch 3 spoke rear wheel to my bike the centre wheel cap engages into a cup that is held in place by the centre bolt

John Re

Melbourne Australia