fork air pressure tubing?

[mvalenti]

My 1980 GS850 has a plastic airline that connects to both Schrader valves atop the fork tubes. Do they sell replacement kits for this? it just started leaking. All the connections are compressions style brass, and I think are fine, the tube is pretty beat up and would like to just replace that. Not sure of the material.

Thanks,
Mark

[Burque73]

How are the springs? If you go with Sonic fork springs you won't need air anymore and can cap that valve off.

[bwringer]

The "balance tube" is some sort of aftermarket or homemade kit; it's not something your bike came with from the factory.

The 1983 model had a similar arrangement, but it involved sealed collars just above the lower triple. I guess there was some inexplicable craze in the '80s for using air pressure in forks. Maybe Suzuki needed to use up a train load of incredibly weak springs. Just a terrible, doomed idea all around; the air pressure wears out seals sooner, and is highly prone to failure. The best way to go is as Burque noted; straight-rate Sonic springs in the correct rate with no added air pressure.

Anyway, your best route by far is to just get rid of the air tube system. Since it isn't stock, we have no idea exactly how to accomplish this without pictures.

Your stock forks have those weird angled aluminum caps, with brass fittings screwed into them and standard Schrader air valves (as used on a tire). There was also originally a chromed cap that screwed onto the air valve bit.

Depending on how the balance tube kit worked, it could be as simple as replacing the valve cores. If it replaced the brass fitting screwed into the fork cap, then you might need to scare up some on fleaBay, or post a "parts wanted" ad here.

Here's an example from fleaBay:

https://www.ebay.com/itm/78-83-SUZUKI-GS850-GS1000-FORK-CAP-ASSEMBLY/224385784082?epid=1211816616&hash=item343e6f5912:g:180AAOSwzQhgTg8e

[Nessism]

I agree with ditching the air, but if you must... McMaster-Carr sells all kinds of tubing. I suspect some FEP tubing would be good. Use calipers to measure the OD and then order accordingly.

https://www.mcmaster.com/tubing/plastic-and-rubber-tubing-for-flow/connection-style~compression/uv-resistant-hard-plastic-tubing-for-chemicals/

[mvalenti]

Thank you all for the responses. I may need to bite the bullet and get springs.

[mvalenti]

Thank you, yes I was fine with finding the size, just wasnt sure the material to hold up to the fork oil.

[Rob S.]

Whatever you do, DON'T use a regular air pump on your forks, even though it may be a standard air valve. That would blow out the fork seals. I'll post a picture of the proper air pump.

[Gorminrider]

My 1980 GS850 has a plastic airline that connects to both Schrader valves atop the fork tubes. Do they sell replacement kits for this? it just started leaking. All the connections are compressions style brass, and I think are fine, the tube is pretty beat up and would like to just replace that. Not sure of the material.

Thanks,
Mark

That sounds like a Honda setup I had on a GL500....you might look toward them.... I don't like the air setups on Suzuki much- kind of tricky getting both sides the same(which the Honda setup cures)..a bicycle pump and A SPECIAL LOW PRESSURE AIR GAUGE are wanted carried in the tool kit if you haven't had the bike long enough to know that.

.....If you were to simply ignore it, or even put some spacers in to pretension the springs or even fiddling with fork oil weight (meh), before you go for the stiffer springs....

I will mention too that lifting the front wheel off the road, cracking the valves, will equalise the pressure. You might even hear a little "phhht" ! The same thought applies to all bike because they all have airspace and are supposed to be sealed airtight...but pressurised forks require even better seals...

[Rob S.]

image.jpg

The proper pump for a fork air system, such as came on my 11EZ. I don't run any air in it, though, as I installed new straight rate springs.

[Gorminrider]

Nice! but a small portable bicycle pump works too. Though indeed, removing a bicycle pump always gives a little "whisht", which is about 2# of the pressure so carefully applied and is awkward.

[bwringer]

Whatever you do, it's important to get this sealed up; even without added pressure, the air trapped inside the forks acts as a secondary spring as the forks compress. And if the balance tube is broken, it's probably making a mess.