K75 Fork Spring Spacers

[TimTyler]

The first real maintenance I ever did on my K75 was to rebuild the forks with Progressive springs. Now I'm wondering if I may have included too much spacer length.

If you have a <1991 K75 (not Showa forks) I'd be grateful if you could measure the distance from the ground to the lower fork bridge clamping bolt head center with the bike on the center stand and the front wheel straight forward.

Mine is 33.5". If that is higher than normal than I have too much spacer tubing in the forks.

If you don't have a fairing in the way, you could measure from the top of the fork tube to the wheel axle. Mine is 32-1/8".

Thanks in advance!

[johnny]

greetings...

dont know...

butts on my old 94 k1100rs... i installed works performance front spring and used the long spacer... it was perfect...

on my present 96 k1100rs... i installed works performance front spring and used the long spacer... couldnt ride it fast or far... the front was too stiff... every imperfection in the road transferred to the handle bars and seat... it was miserable... replace them with one size smaller and it was perfect...

2 rs motobricks with same part number maraschino fork tubes and innards... 2 different spacers needed for the perfect ride... 

so it goes...

j o

[TimTyler]

Thanks, JO.

I just put a level on the valve cover (off center stand with both wheels on the ground) and I can see that my bike points up in the front. Surely the Germans would not have designed a bike that was not level! :)

My OCD self is now pulling the spacer from the forks. The one that's in there is 2.75" long. According to some BMWMOA threads I found 2.75" is the recommended default. I'm going to cut it down to 2".

[TimTyler]

FWIW, if there's no fairing in the way, getting the springs out is fairly easy.

Support the bike on the center stand and with something under the engine.

Remove the instrument cluster, then un-clamp the handlebars and slide them back a few inches onto a towel over the tank.

Use a gear puller to depress the spring retainer (you can almost tighten the screw by hand) then pry the snap ring from the top of the tube.

Remove the gear puller. The spring retainer will not shoot out, but it might pop out enough to fall to the floor. Mine was stuck and had to be coerced with a wiggled wrench and some down-tapping with a screwdriver.

[johnny]

the oem special tool is known as the wiggled wrench... it can only be ordered at your local dealer... butts only by bmw master technicians and occasionally obsessive compulsive motobrickers...

just a note... timtyler gotts the k75 forks... the maraschino k1100 forks are different...
 
j o

[TX brick]

33.25 or so on mine. With the fairing in place it is hard to see. Mine are F&S "S" forks that are untouched as far as I know. I know the history of the bike from '93 and 5000 miles. Top of upper fork bridge to axle center is 31 and 15/16ths.

[TimTyler]

Thanks, Ron.

We have matching bikes; both 91 RT's. My sn ends in 6199774.

[TX brick]

6199732 here.

[TimTyler]

Following up....

My front end feels a little more comfortable now, and the bike a tad lower.  :clap:

[mack75]

Hi, I have replaced the rear shock which was in very good condition but useless with a new KSS rear shock which transformed the rear end, this has I feel shown up the  front end now. The bike is a K75s with 26,800 miles. Looking back through its service history the last owner had the fork oil replaced and new seals fitted at 20,000 miles. The forks to me feel too hard, fine on smooth fast highways but on other less used roads it is not so good.
My local MOT testing station tested the bikes fork function as part of the annual test required and said it was fine. The bike now has new Avon Road Rider tyres fitted.  I have found out that the 75S has "sport" springs fitted by BMW and that they use a lighter fork oil than normal 10wt oil. Is the 75s a stiffer fork action for it's sportier role ?  I suspect the garage has put 10wt fork oil in at the last oil change. Any ideas please.
Thanks Mac