My '81 GS1000G

[Guest]

I bought this unseen from a guy on ebay, had it couriered to me due to distance.
It looked great from the ebay pics and even when it arrived, but after sitting in my garage for a couple of days I realised that it had an oil leak, split brake hose and a rusty tank







Had the tank blasted, just need to POR15 it



Fitted some braided lines on the front and replaced the fibreglass mudguard for a chrome GS750 one




I had to take the micron fork brace off and lift the fork gaiters to fit the mudguard and found a load of fork oil sitting in top of both forks




So I've ordered some new oil seals and dust seals for next week and I've found the air valves are missing from the tops of the forks
Any ideas on what the previous owner has done and do I need to rectify this problem too ?

[hjfisk]

Is that a early front end and brake calipers or is that what came on them on that side of the pond? Our bikes went to the later style calipers in "80' I believe. At least all the 1980's I have owned had the newer calipers

[GSX1000E]

You are not missing air caps on the top of your forks. They are missing the rubber caps. You have adjustable pre-load caps on your G like we got on a few models like this 1100E.
Hard to see in the fiche but it comprises of part number 23 and up to work correctly. http://www.partsoutlaw.com/oemparts/...b91/front-fork
It might take quite some effort to clean the rust from those and get them to turn again. There are three steps that adjust the fork spring pre-load similar to your rear shock absorbers.

[Brendan W]

My 81 850G, which came from Nottingham, had no air valves either. Looks very like what you have, ramp preloaders, three position, turn clockwise to increase load and the springs are about 50mm longer than stock.
How is the front brake on the CB200 ?

[mushroom]

You are not missing air caps on the top of your forks. They are missing the rubber caps. You have adjustable pre-load caps on your G like we got on a few models like this 1100E.
Hard to see in the fiche but it comprises of part number 23 and up to work correctly. http://www.partsoutlaw.com/oemparts/...b91/front-fork
It might take quite some effort to clean the rust from those and get them to turn again. There are three steps that adjust the fork spring pre-load similar to your rear shock absorbers.

Great, thanks for the info

Is that a early front end and brake calipers or is that what came on them on that side of the pond? Our bikes went to the later style calipers in "80' I believe. At least all the 1980's I have owned had the newer calipers

I've no idea this is the first GS I've owned, I only know it's an '81

My 81 850G, which came from Nottingham, had no air valves either. Looks very like what you have, ramp preloaders, three position, turn clockwise to increase load and the springs are about 50mm longer than stock.
How is the front brake on the CB200 ?

The brake on the CB200 varied to how fast you were going Round town it wasn't too bad but coming down from anything over 40 was a bit of a gamble. Those cable operated discs never caught on and I know why

[Flyboy]

Nice find, good solid base to work from, looks like someone has replaced certain bits with earlier model bits, those are the early calipers that went with the solid discs, looks like the PO has replaced the calipers at some point, the later calipers that went with the vented discs on the '81 and up, carried the rectangular pads, not the round hockey puck type.
The earlier forks had the preload adjustable top end, the '81 and up had the valves for air.
I think, this bike had a front end and everything forward was replaced, he obviously got an early model front end, probably put his original '81 discs onto the front end he got to upgrade the stopping power.
Regardless, good bike you have there, will be watching his one with interest.
Just for sh1ts and giggles, and peace of mind, remove the tank, and you will see two parallel frame tubes either side of the main spine, run your fingers along the bottom of these two tubes, if the frame is bent from a front end prang, that is where you will feel it, but I highly doubt it, these things are built like tanks.
First GS you say, you are so going to fall in love with it, welcome to the club.

[mushroom]

The earlier forks had the preload adjustable top end, the '81 and up had the valves for air.
I think, this bike had a front end and everything forward was replaced, he obviously got an early model front end, probably put his original '81 discs onto the front end he got to upgrade the stopping power.
Regardless, good bike you have there, will be watching his one with interest.
Just for sh1ts and giggles, and peace of mind, remove the tank, and you will see two parallel frame tubes either side of the main spine, run your fingers along the bottom of these two tubes, if the frame is bent from a front end prang, that is where you will feel it, but I highly doubt it, these things are built like tanks.
First GS you say, you are so going to fall in love with it, welcome to the club.

Thanks Flyboy after falling off my chair and nearly having a heart attack I ran out to the garage and ran my fingers along those tubes. Straight as a die, phew
I just checked on Robinson's Foundry for fork parts and they list those air valves for '78- '79 so I don't know how early a front end I've got on mine ?



I've got a magazine test ( motorcycle mechanics January 1981) and it looks like the same calipers as mine. I'll scan the full report it and upload it to my photobucket tomorrow
I read your rebuild on your G and was impressed with how well you documented everything, getting a reply from you has made my day
I'm searching for a decent original seat for mine as it's currently fitted with some plastic based ugly thing that wobbles when you sit on it

[Flyboy]

Yes, I thought as much, you can go to war in these things, the only frame I ever bent was on my GS850G when I T-Boned a car at 140kph, and only just a tiny kink in the one tube, wheel was buried between the header pipes.
I, needed quite a fair amount of work though.
the problem with an international forum is that bikes were speced out differently for different markets, so what may have been the norm in the USA, may not have been seen in the UK.

[landshark]

the problem with an international forum is that bikes were speced out differently for different markets, so what may have been the norm in the USA, may not have been seen in the UK.

Too true, i have an 1980 1000G and i have the newer brakes and it came with the preoload caps, not air.
How did you have the inside of the tank blasted?

[mushroom]

Too true, i have an 1980 1000G and i have the newer brakes and it came with the preoload caps, not air.
How did you have the inside of the tank blasted?

I took to a local company that specialize in classic cars.
As far as I am aware they use plastic media and rely on the ricochet of the media inside the tank to completely nuke it.
Then they coat it in zinc phosphate to stop it reacting to the moisture in the air
I used these guys as they have a good track record

[mushroom]

I think I solved the problem with the air valves on the front forks. The U.K. market didn't have them
Just dug out the owners handbook it says England and Ausrtralia only had preload caps

Also it needs less fork oil 213ml each fork instead of 251ml for air adjustable ones

[nino]

I know what you mean about the cb 200 brake, I restored one last year back to original,
it was a police bike on the Isle of Wight. Great fun to ride but that brake scary in the wet.

Cheers

[Brendan W]

Is there a mention of the fork oil level. I'm putting approx 250ml into an 850 with ramp preloaders to get a target level of 140mm from the top.

[mushroom]

Is there a mention of the fork oil level. I'm putting approx 250ml into an 850 with ramp preloaders to get a target level of 140mm from the top.

Sorry,there's no mention of levels in the handbook, just quantities.

[mushroom]

So I've got this far today and now I'm stumped



The fork cap appears to be 22mm and made of butter or something just as soft
I tried undoing it before undoing the fork clamps and the spanner just chews into the small raised castellated nut on top.
Am I missing something or is it just trial and error with a pair of vice grips ?