Oceania GS1000G Fork Question

[Guest]

G'day fellas, new member and first post, I hope I haven't cocked up the procedure or broken any rule.

I currently have a 1980/81 GS1000G on my lift and are seeking information on the correct oil volume for these specific forks.

All of the manuals and 'G' supplements that I have seen depict a fork with an air valve. These forks have a manual pre-load adjuster and in-line axle.

I have been able to locate a parts list but the service specifications, including fluid volume and static spring length, have evaded me.

Can anyone help shed some light on this for me?

Andy

[Steve]

I have seen many different levels, myself, and have come to adopt what I feel is a better method.

Sorry, it involves a bit more work, but is much more accurate.

Remove the fork leg from the bike. Open the top, remove the spring. With the fork leg collapsed, set the fluid level to 6" (150mm) from the top.

I do this by overfilling, then using a vacuum pump to suck out the excess. I use a rigid piece (coat hanger) to hold the suction tube straight, and have a zip-tie set to the proper distance from the end. Simple process to fill the fork tube, insert the suction tube, turn the pump ON, wait for the suction to end, turn the pump OFF and put everything back together.

.

[jsandidge]

Welcome aboard the GSR Andy. I love your videos and have been following your channel for quite a while. You won't be sorry following Steve's advice, he knows his stuff.

[Dogma]

Welcome Andy. I've been following your rebuild as well. I even posted a few comments I hope were helpful, a couple months back.

Since Suzuki can't find this configuration of the bike either, I'm suspecting that some PO swapped the forks, or swapped in the adjustable preload caps instead of the stock air caps. The fork tubes I saw in your video this week look exactly like mine, so I think it's possible the preload adjusters may be all that was swapped. I think I'd look up which 37mm forks from Suzuki (KYB, I think) had preload adjusters, then try to make some reasonable decision about oil level.

...

Remove the fork leg from the bike. Open the top, remove the spring. With the fork leg collapsed, set the fluid level to 6" (150mm) from the top.

I do this by overfilling, then using a vacuum pump to suck out the excess. I use a rigid piece (coat hanger) to hold the suction tube straight, and have a zip-tie set to the proper distance from the end. Simple process to fill the fork tube, insert the suction tube, turn the pump ON, wait for the suction to end, turn the pump OFF and put everything back together.
...

Steve, does your method account for adjustable preload? Those adjusters have their top seal in a piston below the adjuster, instead of at the top of the fork tube like our air forks. Going from what I saw in the video, that seal is maybe 60 mm lower in the tube, so air pressure with the same oil level could be much higher when bottomed out.

If RichDesmond doesn't chime in on this thread, maybe shoot him a private message here on the forum. He seems to be in charge over at Sonic Springs (recommended), and is very knowledgeable about suspension setup and our old bikes. I have his springs and Racetech emulators in my 1000G and I love 'em.

[2BRacing]

G'day fellas, new member and first post, I hope I haven't cocked up the procedure or broken any rule.

I currently have a 1980/81 GS1000G on my lift and are seeking information on the correct oil volume for these specific forks.

All of the manuals and 'G' supplements that I have seen depict a fork with an air valve. These forks have a manual pre-load adjuster and in-line axle.

I have been able to locate a parts list but the service specifications, including fluid volume and static spring length, have evaded me.

Can anyone help shed some light on this for me?

Andy

Welcome to GSR Andy!

I am also working on a 1981 GS1000G that I recently bought from my oldest brother. There were two types of forks for different geographic markets: the air forks, and 4-way spring pre-load adjustable forks.

The specifications for the spring pre-load adjustable forks are as follows:

Oil volume: 213 ml
Oil level: 203 mm
Spring free length: 459 mm

The specifications for the air forks are as follows:

Oil volume: 251 ml
Oil level: 140 mm
Spring free length: 416 mm

The oil level is measured with the spring removed, and the inner tube pushed all the way down, and measured from the top of the inner tube.

These specifications are from the OEM Suzuki Supplementary Service Manual for GS1000G. I have sent you a PM regarding the specifications.

[Steve]

Steve, does your method account for adjustable preload? Those adjusters have their top seal in a piston below the adjuster, instead of at the top of the fork tube like our air forks. Going from what I saw in the video, that seal is maybe 60 mm lower in the tube, so air pressure with the same oil level could be much higher when bottomed out.

I have heard of some forks with adjustable preload, but have never experienced them, nor have I heard that they had a different configuration.

2BRacing posted specs for the two types of forks. It appears that the springs are about 60mm shorter, as is the fluid level, so it appears that my number might have to change if I do any forks with adjustable preload. The equipment will remain the same, I'll just slide the zip-tie up a bit.

[hijack]

If RichDesmond doesn't chime in on this thread, maybe shoot him a private message here on the forum. He seems to be in charge over at Sonic Springs (recommended), and is very knowledgeable about suspension setup and our old bikes. I have his springs and Racetech emulators in my 1000G and I love 'em.

What rate springs?
What weight oil?
How many turns on the emulators?

I have the 1.1 springs, 10w oil and 2 turns out. Seems to work OK, just wondering if there is something better.
[/hijack]

.

[Johno]

My June 1981 build GS1000G purchased new in Sydney Australia came with preload adjustable forks from the dealer.

My previous 1978 GS1000HC came with air over oil. The same model sold in the UK and Europe.

[eddypeck]

Sorry I can't answer you question, but I've just subscribed to your YouTube Channel :-D

[Dogma]

...
[hijack]

What rate springs?
What weight oil?
How many turns on the emulators?

I have the 1.1 springs, 10w oil and 2 turns out. Seems to work OK, just wondering if there is something better.
[/hijack]

.

I have the 1.0kg/mm springs and whatever oil and settings Racetech recommended based on my riding style. There's more to adjusting the Racetech units than the number of turns, and since I was completely happy with the recommended settings, I didn't mess with it enough to get familiar with it. Probably this spring I should dig that info out so I can replace the fork oil. It's not as fresh as it used to be. You have the MikeXS emulators right? Did they make Any recommendations?

[Steve]

Yes, I have the XS emulators. Since they are only 35mm, they require adapters. I was sent a set of adapters from another forum member, they seem to do the job well.

The settings from Mike's XS suggest starting at two turns of preload, with a minimum of one turn. If I remember correctly, the preload added controls the compression damping, the oil viscosity controls rebound.

.

[salty_monk]

With emulators you start off by adjusting the oil weight to get the REBOUND damping that you want. After that you then adjust the emulator to get the COMPRESSION damping that you want.

If you have an 83 GS1100 fork like I do you also have 4 stages of rebound adjust too so the oil weight is not as critical. They have preload adjust too. Never seen a 1000G with preload adjust on it.

In general the recommended settings work well for most with a 10w oil.

To get the 140mm oil from the top I use the top of a spray bottle (like a simple green spray bottle or something) with the straw cut to the correct length (in this case 140mm). Overfill a bit, rest the spray bottle lid on the top so the straw is now 140mm down the tube... Pump until it stops delivering oil. You can catch the excess oil in a rag.

I am using the same Emulators as Steve and yes they work great but do need an adapter. Unfortunately I don't have any more of those but happy to provide a drawing to someone if they'll make some up for the forum.

[AMO]

Welcome to GSR Andy!

I am also working on a 1981 GS1000G that I recently bought from my oldest brother. There were two types of forks for different geographic markets: the air forks, and 4-way spring pre-load adjustable forks.

The specifications for the spring pre-load adjustable forks are as follows:

Oil volume: 213 ml
Oil level: 203 mm
Spring free length: 459 mm

The specifications for the air forks are as follows:

Oil volume: 251 ml
Oil level: 140 mm
Spring free length: 416 mm

The oil level is measured with the spring removed, and the inner tube pushed all the way down, and measured from the top of the inner tube.

These specifications are from the OEM Suzuki Supplementary Service Manual for GS1000G. I have sent you a PM regarding the specifications.

Thank you so much Ben, it seems I was close, within 1ml anyway. Good enough for the girls I go out with. PM sent.

Andy

[AMO]

Thanks again Ben, https://youtu.be/4zjdsgSX26c

[2BRacing]

You're welcome Andy, glad I could help!

Good going there, pity about that broken bolt/stud - there are supposed to be studs in there (like the left fork). Total length protruding from the flat face = 30 mm, of which 11 mm is the smooth part of the stud, and 19 mm threaded part of the stud.

Looking forward to watching your progress!

Cheers
Ben