More Fork Questions

[DMPLATT]

Sorry guys, I haven't had the money to get a manual yet.

'83GS 750E Seems hard on bumps and road patches. I was told by the owner that the fork seals had been done, but he lied on a lot of other things as well.

I see an air vavle on the left fork, but didn't see one on the right fork. Upon further review, the right fork has it on the inside and has a hose connected to another valve on the left fork? So, the left fork essentially has 2 air valves. One to pump air into, and another to apparently send air to the right fork. Anyone heard of this before? I tried checking air pressure but got none. actually I pushed the valve in with my finger nail and just a tad of oil leaked out. (hardly noticeable) May have been moisture, couldn't tell for sure.

Also, where do I bleed the fork oil and where do I refill it so I can change the fork oil?

I don't see any signs of oil on the forks (maybe cause it's empty?) I should state that the bike handles very well. I really don't think anything is wrong, except that over bumps it's a bit rough. Thought I might change the fork oil and add a little air. Except I can't figure out how.

Thanks for the help.

Dave

[gsbill]

Oil goes in the top of your fork tubes...Its common to have the 2 fork tubes "linked" via one air fill..this was actually a mod on bikes many years ago...The air in your forks will be low PSI and will require a low pressure gauge to measure...I dont know the specs, you will have to find someone who knows...You let the oil out at the bottom of the lower fork leg, pump the forks to get the old oil out..put the plug back in and get to the refill. Dont over fill. You will have to find yuour forks capacity and recommended grade of fork oil. Have fun! Its an easy job(after the first time).

[DMPLATT]

I don't see any where at the top of the tubes to put oil? MaybeI have to take off the headlight fairing? I put in about 10psi with a bike pump, and about an hour later there is NO pressure? I'm thinking fork seals.... Problem still is that I have NO center stand.

All help is greatly appreciated.

Dave

[gsbill]

Ok...follow your tubes up, at the top, there will be a cap which unscrews. You may have to remove something to get at the cap...There are quite possibly o-ring seals(round rubber rings) on your tubes, under the triple clamps, that also are air seals...If your tubes are not leaking oil at the fork seals, they are probably OK...10 psi may be a fuzz on the high side. Dont put any more than that in until you can verify the proper amount.

[Billy Ricks]

3-8 lbs on an '83 is about what you want to run depending on load.

[DMPLATT]

What if the air leaks out after about 1/2 hour?

[gsbill]

Pump your forks up with air and spray some soapy water where ever you think there may be a leak..Look for bubbles...Around the triple trees, caps, fork seals, etc..

[Mr. Jiggles]

Be careful unscrewing those fork caps - the fork springs will pop them off pretty forcefully. Also, with the caps off, the bike will probably want to fall forward.

[oldschoolGS]

Standard fork oil is #10, capacity is 10.4 US oz each leg, and standard air pressure is 2.8psi. There are two rubber o-rings on each fork tube air clamp that seal in the air pressure on each tube, this or the connector line between fork tubes could be the source of your leak. In my attached photo, the air clamps are visable just below the top triple clamp with the air valve on the left tube. I have never run any air pressure in the stock tubes, just #15 oil and heavy duty springs with preload adjusters. If the tubes are not leaking oil, troubleshooting for the air leak could be more trouble than its worth. Good Luck, Ed.
1983 GS750ED

http://groups.msn.com/SuzukiGSGarage/gs750edbacktolife.msnw?action=ShowPhoto&PhotoID=3194

[Billy Ricks]

Put the bike on its centerstand if you have one and elevate the front wheel before taking the caps off. This will keep the springs from being too much trouble.

You can make preload adjusters out of 3/4" id PVC tubing so you can run without air. You measure the length of the fork with the bike elevated and the fork fully extended. Then measure again with the bike on the ground and your weight in the seat. The difference is called sag. If you want a plush ride use about 1 3/4" of sag. For a firmer, more agressive ride shoot for about 1 1/4" of sag. You place the PVC spacer on top of the spring with a fender washer between the spring and the spacer. You'll have to experiment a little with the length of the spacers.

[DMPLATT]

I did the soap and water test and couldn't see any leaks in the valve or hoses. After about 10 minutes I went back and checked the air valve to see if there was still air in it and some oil squirted out.

I guess my question now is, what seperates the air from the oil? Maybe my fork seals are bad. I don't see oil on the tubes after riding, but there is some markings. I always assumed this to be normal?

Also (I really am mechanically inclined) but on the top of my fork tubes are where my handlebars mount. I'm assumning then, that I would have to take both bars off to get to the caps on top of the fork tubes? Also, the only drain plug on the bottom of my forks is a small phillips head screw by the axle?

Thanks.

[earlfor]

You are correct, that is the drain screw for the fork oil.

Earl

Also, the only drain plug on the bottom of my forks is a small phillips head screw by the axle?

Thanks.

[Jeff Tate]

Also, if you do want to take off the fork caps on top you'll have to loosen the top bolts on the triple clamp to get the caps to come loose. Just don't forget to torque them up when finished.

[Anonymous]

hey there dave! I have the same problem with my bike....sort of, i dunno if you got how it works, but i might explain better.

our forks are air filled.
on a stock bike, you fill one side, then you fill the other side.
a pain to get exactly even...but do-able.
from what i read, the modification is...hey, just connect the forks with a small tube, then you just have to fill one side, and the tube will equalize them...

so on my bike, at the top of the left fork, there is a nut i can screw off, and there is a valve to fill them.

under, at the bottom of the valve there is a little nipple, a hose is attached there, and runs to the other fork, attached to another nipple.

this hose is the size of.... the inside of a bic pen....the part that holds the ink.

the other nipple...is just attached to an aluminum cap, that screws onto the right side valve. you do not see the valve cause its covered by this cap.

my little hose was leaking, so i finally go a perfect size hole....but broke the nipple.

i could not find an exact replacement, so i got bigger nipples, and a different size hose. all is well again...

BUT if you need the hose...or tubing, send me an email with your address, and i will gladly send it to you, i will even pay for the stamp!!!

the tubing cost me nothing, so ill pass the savings to you!

ebayinmontreal@sympatico.ca


Max