Measuring fork oil

[conybeare]

Hi All,

Does anyone have a trick for measuring fork oil height/quantity with the fork tubes on the bike with springs installed?  This is for a 1990 K75S (note that from 91-on the fork fluid level differs). I installed new springs today and had a little fork oil eruption from the top of one fork tube when removing the old springs. I'm trying to get one leg back up to the proper level without draining and refilling. That leg also happens to have a JB-Welded fork slider drain plug - hence my desire to top up/measure fork fluid level without draining the fluid (which would require removing the fork tubes). I was wondering if someone might have some trick for measuring from the top of the fork tube.

If there is no trick for this, it seems the easiest solution would be to remove the wheel and just pull both fork tubes together (with brace still attached) and flip upside-down to drain.

Thanks!!

[johnny]

greetings conybeare...

look here for quantities...

what i do is use is honda ss-8-10 fork oil... fill a measuring bucket with the proper quantity... suck it out of the measuring bucket with a meat injector n fill er up...

note... the meat injector has a slack jaw needle... i cut the end off straight so the juice goes straight in hole instead of squirting out the side...

j o

[Motorandy123]

Late Info. According to Racetech you can set the oil to 140 mm down from the top
with the spring removed. This is a better way to spec it as sometimes you don't
know how much is in there!

[TimTyler]

Late Info. According to Racetech you can set the oil to (#140 mm down from the top...

That doesn't sound right to me, especially if the spring was removed. Different springs and spacers will occupy more or less space, and how much is the fork supposed to be compressed in the slider when you take that measurement??

The forks can also be drained by removing the wheel and then the large hex-bolt that screws up through the bottom of the fork slider. That won't get all the fluid because of the spacer (fiche #17) but you'll get most of it. I'm not an expert so a get a second opinion before you try that.

Additionally, with my old-style fork (March 1991) that spacer creates room to use a longer fork oil drain screw. The #17 spacer does not move in the assembled fork. About half of the threads where my fork oil drain screws go were stripped by a PO (not uncommon) and I was able to use longer screws to grip onto the threads that remained even though the new screws are a little exposed on the fork interior. That'll only work if you have that spacer though.

[mystic red]

Reminds me off when I was teaching my Dad how to reload ammo. I came back and he told me that the first load of powder filled the brass to the top so he just dipped the rest. :eek2: So I had to pull all the bullets and started over, weighing each charge. :nono

[Motorandy123]

If you go to Racetech's web site they tell you info about the stock forks on your bike.
They also spec the amount of oil to add with the springs removed and the fork fully
compressed by measuring down from the top. The 140 mm is for "S" forks. Though I
just changed my oil and the stock 280 ml gives about 200 mm.

The headspace in a fork is the important thing. It creates a progressive air spring.
Too little oil and you will bottom easily...

[BobZ(IL)]

On my airhead I've used skinny dowel rods as dip sticks to check levels. Don't know if it would work on the K.