final k75s suspension questions

thanks again for all the previous help, patience, and indulgence as i get
this bike into shape for the long haul. with a little luck, this'll be
my last plea for help and i won't have to bother anyone further with
remedial mechanical issues.

to bring you up to date, i wanted to change leaky fork seals, so:

i drained the forks, took the fender, fork brace, brake calipers, and
wheel off. then i unbolted the fork sliders at the bottom, and they slid
right off with the damper rod sticking out about ten inches from the
bottom of the fork tube.

(question #1: should it be sticking that far out? some of the stuff
i've read makes me wonder about that.)

to my surprise, i had none of the parts that the clymer's manual said i
should have inside the slider. no bushings, no washers. the only things
in the slider were the seal at the top and a ~1-inch tall spacer at the
bottom. when i compared the new seals with the old, i noticed a big
difference and called the parts guy. he said he'd given me the seals for
the bmw made forks, and that unfortunately my forks are actually showa
forks. i thought this might account for the difference between the
clymer guide fork description and the real life situation i have before
me.

i then looked for info on the showa forks and found Tom Coradeschi's
showa fork rebuild page on the ibmwr site
(http://www.ibmwr.org/ktech/showa-fork-rebuild.shtml .) not having
taking apart the upper end of the forks, i don't have the firmest grasp
of all the info in his explanation. i do, however, understand that
according to his showa fork diagram (at http://www.ibmwr.org/ktech/showa-
fork-rebuild.gif ) i should still have some washers and bushings in the
sliders. as i mentioned, i don't have any such parts in the sliders.

question #2: i can't tell from the diagram whether the washer and
bushing should fit in the fat part of the opening at the top of the
slider. it doesn't appear that there is room for much more than the oil
seal and the circlip. so should the washer and bushing sit inside the
slider? that doesn't seem quite right either.

question #3: i can't seem to find an authoritative statement on the
proper assembly of the showa forks. what is the danger of forgoing the
washer and bushing, as my bike's previous technician evidently did?
would this contribute to the leaky seals and/or the soft ride? would it
cause handling problems?

question #4: once i decide how to proceed with respect to the innards,
i'm planning on putting everything back together in the order i took it
off. since i haven't moved the fork tubes, this should keep the front
end properly aligned, right?

question #5: somewhat unrelated: i figured i might as well do an oil
change while i'm doing all this. i noticed a couple oily spots on the
bottom of the oil pan, so i'm going to reseal that too. but with what?
i've got a silicone sealant for motorcycles, but i don't know if it'll
handle the heat that an oil pan gets. it doesn't have a temperature
rating, but it's called permatex motoseal 1 ("ultimate gasket maker -
gray.) what would a smart person use?

i welcome and thank you for answers to any of these questions. much
appreciated!

 

"...I had none of the parts that the Clymer's manual said..."

"...the difference between the Clymer ... description and ... real life"

The common thread to all of your questions up to this point is, you
don't have the correct and complete information you need. These
questions (and many more to come) will be definitively answered when
you buy the genuine BMW service manual.

Nothing. If the sump is like any other bike sump I've seen, it will
use an O-ring between the sump and the engine cases, and doesn't need
any sort of sealant. Adding sealant will only screw things up, find
out what the real problem is and don't make things worse. I could be
wrong about the O-ring, but I'd be very surprised if I was. If the
leak is from a drain plug, renew the soft crush washer and torque it
to the correct value.

 

Unfortunately he does not know what he is doing. Unless you did
not tell him that you had an 'S' (and he should have asked anyway)
there is no excuse for providing the wrong parts.

Well... You've found the best online source for information for your
bike. You should check recent archives and perhaps subscribe because
there is some discussion right now about K75 fork rebuild. (Idon;t
recall if it was Showa or BMW forks, though.) Ask your questions there
and you will get as close to authoritative answers as you will find
this side of the factory. In addition to some highly knowledgeable
amateurs, there are also professionals who participate. They do tend
to run a bit low on political content though.

There is a weep hole between the water pump and oil pan. It is
a frequent source of leaks. (Check the IBMWR tech pages for water
pump rebuild.) Best recommendation I've heard is to clean the engine
well enough to remove existing oil, ride a few miles and dust with
talc to identify the source.

Silicone seal is used on the valve cover so I don't know why it
would not work on the oil pan.