K 75 fork oil change

[jamesking]

Attempting this for the first time on my 93 k75s.
I have the plastic caps off and the oil drained. The Clymers manual say to use a 22mm
open end to hold the (retaining?) nut while backing out the filler plug. Mine is a 17mm
and maybe the 22mm was a typo, but either way I'm having a heck of a time holding the thing with an end wrench--it's somewhat recessed-- while I try to back out the filler. I can only get the tips of the end wrench in there and I'm beginning to mangle the nuts.
Any suggestions? I thought I'd read somewhere there's a special wrench, but the Clymers only says end wrench.
Thanks in advance,
james

[PHMarvin]

Hi, James,
It's a bitch, but it can be done. I have a 17mm wrench which is bent just at the jaws, making it much easier to hold the cap while breaking loose the fill plug. When you do get it loose, you'll know not to tighten the plug to within an inch of its life!

I hope you've thought about how you are going to get the oil into the fork tubes. I have a set-up, a bottle (old gear oil bottle) with the bottom cut out and a plastic hose onto the cap. The hose fits into the fill hole and I tie the bottle up above the fork tube. I put the oil (first 220 ml, then another 200 ml) into the bottle and in a few minutes, it has run into the fork tube. Then I switch sides. Make SURE you have first replaced the drain plugs (Duh!). DO NOT overtighten the drain plugs; the threads strip easily!

[jamesking]

Phil,
Thanks for the info. Now that I know there's not some basic concept I'm missing, I'll give it a more concerted go. Is the bent 17mm a device of your own creation? Before I bend (break?) one of mine I might head over to the parts house to see if they've got something tricky. As to the re-fill, I guess I just figured to use a small funnel to get the stuff in there. If there's some reason that won't work, I'll definitely give your method a try. I love this site.
Thanks again,
james/ 1965 R50, '93 K75S

[PGlaves]

This is a bit tricky to describe but I am going to try. And, what I am going to suggest might be a bit more work than typical - but a lot less work than replacing kludged fork tube tops.

So here goes: If the top of the fork tubes is slightly lower than flush with the top of the upper triple clamp then the fork cap flats seem recessed, and it is difficult to get a wrench on them. If the actual top of the fork tube is flush with the top of the triple clamp then the wrench can lay flat across the flats on the fork cap. It sounds to me like your fork tubes may be slightly down in the triple clamps.

If so you have two choices. Find a way to make a wrench work, or loosen the clamping on the fork tubes and raise them to be flush with the triple clamp so the fork tube caps are above the triple clamp top surface.

I don't know the history of your bike but folks often lowered these by sliding the fork tubes up a bit in the clamps - and if somebody put it back after that they might have slid the fork tubes too far down.

Good luck.

[roncooper]

to the re-fill, I guess I just figured to use a small funnel to get the stuff in there. If there's some reason that won't work, I'll definitely give your method a try. I love this site.
Thanks again,
james/ 1965 R50, '93 K75S[/QUOTE]

I use a small funnel. Pour the oil in at a trickle, or it will overflow.

[bikerfish1100]

of course, there's no reason I'm aware of that would keep you from pulling the large fork caps off and pouring oil in from there. After all, you open those babies up to do a spring change, and the heavens don't come crashing down. Gives you a mighty big opening to work with- tough to spill or get things messy. Of course, sometimes recompressing the springs for cap replacement can be a bit annoying :banghead but it is an option.

[PHMarvin]

Phil,
Thanks for the info. Now that I know there's not some basic concept I'm missing, I'll give it a more concerted go. Is the bent 17mm a device of your own creation? Before I bend (break?) one of mine I might head over to the parts house to see if they've got something tricky. As to the re-fill, I guess I just figured to use a small funnel to get the stuff in there. If there's some reason that won't work, I'll definitely give your method a try. I love this site.
Thanks again,
james/ 1965 R50, '93 K75S

Hi, James,
I would advise finding a cheap 17mm wrench, heating and bending the working area so you can get the jaws onto the flats to hold the cap while loosening the fill plug. I don't know where the wrench I have originated. I've had it for many years.

Be advised, the oil runs very slowly into the fork tube. You will spend a LONG time with a small funnel. My method is similar (tube from the funnel-shaped cap), but I don't have to be there to hold it; I can tie it up above the fork tube and let gravity do the work.

[Ted]

I use a horse syringe, I think from a group buy off the IBMWR list many years back, that works like a champ. Stick it in the hole, squeeze the plunger, done - no mess, no fuss. I think the guy who organized the buy got them at a Tack Shop or maybe a Vet's office? I do know fork oil is much different than the intended use (think animal husbandry ;) )

[PGlaves]

I just went out and looked at Voni's 1991 K75s and my 1995 K75RT.

In my post #4 above I very neatly described the top of the Marzochi (sp?) forks on the 1991 and earlier K75s. These take a 22mm open end wrench on two flats on the top cap. The Showa forks used on the 1992 or thereabouts and later K75s indeed do have a 17mm hex which is recessed below the top of the fork tube.

My tool of choice would be a quality box end wrench that isn't over beefy in section at the head of the wrench so it would go into the recess. I'm sure there is a special tool - 17mm "socket sort-of" with a handle and hollow, so the Allen driver can slip down inside even with the "socket sort-of" placed over the 17mm hex on the cap.

I made such a tool once from a 13mm socket to fit the lock nut on the bottom end of /5 forks so I could hold the damper rod with an Allen wrench while loosening or tightening the locknut. Just had to weld a handle onto the socket and stick the Allen wrench through the hole in the middle. On the bottom of these forks I never did find a box end that would fit into the recess so gave up and made one.

[TinyTrains]

It is a piece of cake on my 88, but I can see your dilemma.

How about a crow-foot wrench? It looks like an open end wrench, but has a 3/8 socket hole next to the opening for an extension and ratchet. Made to tighten bolts that are under flanges.

http://ecx.images-amazon.com/images/I/51xG8niXSzL._AA280_.jpg

If you have a funnel that will reach the fill holes great. If not, I just cut the top off of a gear oil bottle and use that. Fits perfectly on my C model.

Scott

[tpbyrum]

I have a 92 and the plug is recessed at Paul noted. Several years ago I went to the bargain basement tool shop and bought a cheap open end wrench that fit. I then spent time on the grinder, grinding away the tip of each "ear" of the open end wrench so it would fit down into that recess. The end result is I can get a pretty good hold on the cap while I work the fill plug. You don't need a drawing, just poke the wrench in the recess and start grinding away anything that interferes with it sliding down into the recess. I suppose mine fits into the recess at about a 45 deg angle. It gets a pretty good bite on two flats which is enough.

Single purpose wrench but invaluable when I need it.

[RUDYJO]

I put the measured amount of fork oil into a clear squirt bottle and pushed a
clear plastic tube onto the nozzle with the other end down into the fork. It took
awhile to squirt it in, but I never lost a drop doing it this way.

[jamesking]

Thanks for all the suggestions, most of which would likely work, but I think I'll try the grinding-of-the-cheap-end-wrench routine first, as I think I have a spare 17 to donate to the cause. I got pretty charged with Paul's sort-of-socket idea, until I recalled that the cap isn't actually hex-shaped. I hope to get after it this weekend and post what method worked (!) for me. I'm pretty convinced there's something bio-rythmic about wrenching (and not just because I'm from northern CA), as some days it goes smoothly and other days I wonder if there's any hope for whatever I'm working on. Or me.
But these forums help a person to not feel completely at loose ends.
Thanks, james
About an hour later: I got enthused and went out to the garage after my last post. The first plug came with a little perseverance using the regular 17mm. The second wouldn't follow suit, so I'm a bit embarrassed to say I resorted to a cheap set of vice-grips. Ended up doing less damage, actually, than I was wreaking with the 17, and I'm presently celebrating with a glass of some not-so-cheap sipping whiskey.
Cheers!
james