Front Forks 78 GS1000

[Guest]

My front forks are in need of attention. The front end feels like it is bouncing over bumps, even the small ones, instead of absorbing them. I decided to change the fork oil in them, not knowing what the PO had put in them, he was a big guy, and the bike had a Vetter fairing on it when I bought it last summer. He also advised me that the fork seals had been recently replaced...Put the bike on the center stand, released the air in them, and removed the drain screws. The fluid came out real slow so I let it drain all night. Looked a litle thick. So the next morning, I pulled the fork caps off and removed the springs. I kind of expected the caps to have some spring force behind them as they came off, but it was uneventful. I measured the free lenght of the springs and they checked good. Then I realized that the bike, on the center stand, had not dropped down in the front. I gave it a little push and it went all the way to the bottom. I then leaned on the back, raising the front wheel, and the forks remained bottomed, with the wheel hanging in the air. I have a feeling that the seals are not OEM and that they are too tight on the tubes. I suspect that whoever did the seals did not clean the corrosion from the seal land on the sliders and this is the end result. So my questions are, am I on the right track??...Should I stick with OEM on the seals, and would glass beading the seal lands on the slider give me the results I am looking for??...I tried straight ATF in the forks as I only weigh 125 lbs but now the forks bottom too easily under braking with 12 lbs. of air in them... The ride is still bumpy...Isn't this called too much "stiction" between the slider and the tube ??.......Thanks........BadBillyB

[Dink]

Billy you have a series of problems there,yes replace the seals, I prefer genuine, ATF is 10w30, try a straight 20.
set your static sag, dont use any air!!!! measure the sag and add a spacer on top of the spring to set the sag correctly to start with. Dont forget to fully dis-assemble the forks and replace the other bushes as well as they will cause your stichon more than oil or weak springs will.
Dink

[SqDancerLynn1]

Their should be at a minimum 1/2" of preload on the cap You should have to push down hard to screw the caps on

[JayH]

Don't bead blast the seals w/ them installed on the fork. You will damage the seals and those beads can get stuck in places you won't believe possible.

You mentioned you had 78 GS 1000 forks. How much fork oil and what weight oil did you use?

[Sandy]

You didn't mention whether you had the stock spring preload tubes on top of the springs. These are about a 3" long metal tube that sits on top of the spring. If you didn't have this tube then you already have aftermarket springs like Progressive. This is good as most of the old GS1000 springs really suck big time. The stiction could be coming from the forks tubes being bent or misaligned. Easy enough to check, when you have it apart to change the seals pull the front axle after you've pulled the springs and see if the sliders work freely or not, do this again after you change the seals. If they slide freely but bind after reinstalling the front wheel then you have a misalignment problem. There should only a minimum amount of stiction from the seals. The 20W fork oil seems to work best for me, although I've got about 75lbs. on you. If the PO was a big guy and had the Vetter on it maybe he had extra stiff springs installed.

[BadBillyB]

Thanks for the input fellas,

Dink, Checking for sag would be hard to do as the forks are sticking. If I just sit on the bike the forks dont move. If I push down on them, they go down and stay wherever they stop. What is the correct method/setting for sag?? This can be useful when I get them sorted out.

SqDancerLynn, there is a slight preload on the caps, but they were easy to install. The free length checked good.

JayH, I was talking about bead blasting just the area where the O.D. of the seal contacts the top of the slider. Of course the forks will have to be completely disassembled and the slider masked off inside and out. I used ATF and set the level by the method in Clymer's

Sandy, I was hoping to find something other than stock springs in the bike, but apparently they are factory with the stock preload tube on top. Good point about the front axle possibly being a factor. I doubt it as I installed the front tire myself. I am human though (and not as sharp as I used to be) so I will definitely check that.

If you guy's were going to stay with stock forks and stock springs and weighed 125 lbs (soaking wet) what weight oil would you use?????
Thanks......BadBillyB

[Sandy]

Thanks for the input fellas,
Sandy, I was hoping to find something other than stock springs in the bike, but apparently they are factory with the stock preload tube on top. Good point about the front axle possibly being a factor. I doubt it as I installed the front tire myself. I am human though (and not as sharp as I used to be) so I will definitely check that.

If you guy's were going to stay with stock forks and stock springs and weighed 125 lbs (soaking wet) what weight oil would you use?????
Thanks......BadBillyB

I didn't mean to suggest the axle was improperly installed, although a possibily, but to allow each fork leg to be checked for binds independently of each other to see if there is possibly a bent tube, triple tree or maybe they are misaligned in the triple tree. I know a number of people that have settled on the 20W fork oil. Also you can just add a spacer tube that is an inch longer or add a handed full of larger washer on top of the tube to increase the preload.

[BadBillyB]

I didn't mean to suggest the axle was improperly installed, although a possibily, but to allow each fork leg to be checked for binds independently of each other to see if there is possibly a bent tube, triple tree or maybe they are misaligned in the triple tree.

Good point, I hadn't thought of that, Thanks Sandy, I will check them independently.........BadBillyB

[mkaczmarek]

Front Fork Questions from a newbie...

Hi all,

I'm fairly new to this forum as well as to owning a motorcycle. I have ridden to a limited extent in the past but never owned one myself.

I got a 1979 GS1000E with a Cafe Fairing in very decent shape a few months back (this bike had been standing in a garage for the past 3-4 years). I have been slowly trying to get it back to road worthy status, this brings me to the front air/oil forks.

I was wondering what precautions (if any) I should be aware of/should take when checking the front forks. I picked up an original Suzuki Front Fork Air Pressure Gauge recently. I weigh about ~190lbs (~85kg) in case that might make a difference as to the type of fork oil I should use etc. I have tried to read up on some related threads and there are many various types of oils people like to use, but few of them actually give their reasoning as to why they like to use those oils.

Will I be ok just to check the Air pressure (adjust if necessary) and check the Oil level in the forks? Or should the old oil be replaced with fresh oil?

Any help in this regard would be greatly appreciated and also, does anyone here know of a Guide similar to the "Carb Cleaning Guide" which is really good, especially for people as "green" as myself in this regard.
================================================== ========
"The less you know, the more you believe."
"We thought that we had the answers, it was the questions we had wrong."

[gekkechef]

In my opinion and experience I should forget about the air, first take the forks out and remove the drain-plug and let the old oil get out as good as possible, press the fork inner tube inside, this will help, let it rest 5 min and do it again.
Make sure that the top cap, the spacer (collar) ,the spring seat and the spring, are not in the inner tube, then fill the inner tube with 10-30 fork oil
( don't forget to put back the drain-plug:-D ) until the level is 13 cm from the top of the tube, jerk the tube couple of times to make sure the oil went everywhere.
Using 13 cm instead of 14 cm as advise an using no air at all... Since I did this to my gs 1000 L it behaves far better than using 10-20 oil and air pressure. Gives more confidence when cornering and makes the front end feel stronger at high speeds.
This a quick cheap fix that you can try before think about replacing things.

[BadBillyB]

Finally got around to replacing my fork seals with genuine suzuki parts. Also put new progressive springs in. I am still getting around an inch of stiction, which is unacceptable to me as the ride is horrible. There are no replaceable bushings in these sliders. The fork tubes appear to be straight. I have tried leaving axle nut and spacers and fender loose to no avail. I loosened the lower triple tree pinch bolts and jounced the forks a few times but no luck. These forks are very nice looking for their age except for some minor pitting on the tubes (on the outside of seal) and I would really like to keep them. If I hold the front brake tightly and rock the bike back and forth I can see and feel the lower sliders rocking back and forth. I think this is probably normal but wondered if this may be part of my high speed (90mph) head shake/weave. Am I being anal and just expecting too much from these old units ?? Has anyone else measured the stiction on their forks?? I cant even set my sag as the forks dont even move when I sit all 125 lbs on it. If I push them down they stay down. Bahh.......BadBillyB