80G Fork question

[GLoweVA]

Okay, so i've owned my bike for over 7 years now and just now got around to really look at my fork caps.
It seems that the right one has an air valve while the right one does not.
My right fork has had a leaky seal for a while now and next week I plan on replacing both seals.
I've been trying to read up on the fork seal change in the tech tips and such.

Tonight I checked and the air one had a little bit of pressure. (~1-2psi)

Tommorow I'm changing out the front tire.

Time for the questions:
Which bikes are supposed to have the air forks?
I know some have swapped forkas around and such.

Is it really bad for me to have one each?
Obviously I should run the air one with no pressure.

Has anyone tried a different air valve in there?
the one that in there looks different then the ones on my SG.

Thanks for any input.

[crazy steve]

Your G is supposed to have the air-assisted forks, so hopefully one of them is right. Where the problem might enter is if you actually have a mixed set; a '80-81 on one side, a '78-79 on the other. These used two different springs, with the late springs being about 1/2" longer @ 20.31" but with a softer spring rate.

It's not good to have two different spring rates, so that's something you should correct if that's what you find. If you have the late springs in both, try adding about 15cc more fork oil and maybe a 1/2-3/4" preload spacer then don't run any air in the one.

Make sure both fork caps are the same length into the fork tube as that will affect spring preload too.

A pic of the two caps would be helpful...

[GLoweVA]

Thanks for the input Steve.

I went out and looked at my manual and the pic in there for the G shows the exact pic of what my air valve looks like.
So the question is, is my right fork still an 80 or something else.
I guess next week when I get around to do the seal change, then I'll know for sure when I can measure the springs side by side.

Tommorow morning I take some pics and post them up.
I guess I should search for an air valve/cap in case I do have the correct fork.
I'm thinking that way in the past, a PO may have had an air leak or something like that and instead of replacing the valve, a plug was installed instead.
It's probably not a coincindence that this is the fork that the seal has gone bad in.

[Crazy Damian]

something to check

Something you might want to check before getting parts and stuff, or getting too worried is, if a PO had installed progressive springs then you wouldn;t use the air at all anyways and the difference in the forks wouldn't matter, since they are the same except for the air assist.
When you install progressive springs on a set of forks that have the air assist, you no longer use the air assist, and I think 1-2 psi could just be the weight of the bike showing.

Damian

[jwhughes3]

How can u tell if a spring is Progressive....

Are they pink?

John

[Crazy Damian]

I want to know too!

How can u tell if a spring is Progressive....

Are they pink?

John

thats a question I would like to find out the answer to as well.

Damian

[bikerphil]

The Progressives have a thicker winding than the stock springs and they are dual rate wound. The factory heavy duty ones for the fairing bikes might look like that too. Some of the air fork bikes came with straight wound springs IIRC.

[motoman]

The Progressives have a thicker winding than the stock springs and they are dual rate wound. The factory heavy duty ones for the fairing bikes might look like that too. Some of the air fork bikes came with straight wound springs IIRC.

The 81H being a factory dresser came with progressive wound springs and of course the air assist.

[CaptonZap]

thats a question I would like to find out the answer to as well.

Damian

When you look at the spring, the progressive will will have the space BETWEEN the coils vary from one end to the other.
The space will be small on one end, and get wider as you get to the other end. cz

[GLoweVA]

Thanks for the tips fellas, I knew what to look for to see if they're progressive or not, but I've got to wait to get the fork apart. Currently the Monster is my daily rider/commuter so It'll have to wait until next weekend. I've got the following week off, so I'll time to play with it.

Just got done putting the new front tire on. I had to take the tire down to the tire place down the street, my little compressor didn't have enough umph to seat the beads.

[GLoweVA]

pics

Here's a pic of the right side with the air valve:



Here's a pic of the left side with no valve:



Here's one with the cap/plug removed:



On a pic of what the air valve on the SG:

[crazy steve]

Well, the good news is the two fork assemblies are probably matching. The bad news is that air valve is discontinued; not even NW Vintage has it. You can't use the one off the Special fork because for some obsure reason Yamaha used a different fitting/thread size.

You might be able to find a similar valve at a A/C supply, or there's always this: http://www.airridefittings.com/store...products_id=24 You would have to re-tap the hole for 1/8" pipe but this may be a possibility...

[skids]

The air-assist is bunk anyway. You don't need it. This was another fad like oil coolers for air-cooled engines.

[HobbyMan]

That air valve is discontiunued but there are ways to find it. You are probably going to need the whole cap as the threads are probably no good. If I were you, I would start checking out salvage yard as many other metric bikes us the same parts. I believe they were all made by the same people. When the brass valve sheared off on my G model, I found a replacement and cap on an old kawasaki. My neghbors '82 GS1100 uses the same brass valve piece as well but has a completely different air system. Perhaps you may just get lucky if you look in the right places.

[Rasputin]

That air valve is discontiunued but there are ways to find it. You are probably going to need the whole cap as the threads are probably no good. If I were you, I would start checking out salvage yard as many other metric bikes us the same parts. I believe they were all made by the same people. When the brass valve sheared off on my G model, I found a replacement and cap on an old kawasaki. My neghbors '82 GS1100 uses the same brass valve piece as well but has a completely different air system. Perhaps you may just get lucky if you look in the right places.

+1 on that as my buddies GS has the same air valve as I do on my specials.
I may have a set or two lying around here but I would have to check. I have some MNS forks and some supposedly off an XJ and a few single forks that I have no idea what bike they came of off other than they are Yamaha 78-84.