what forks are these in my 1978 GS1000ec? and other questions

[angrypants]

hi all,

i hope you are all well, on the bright side, it's definitely an opportunity to get to those bikes in the shed!

i bought a 1978 GS1000ec some time ago. Anyway so i pulled the carbs and in process of cleaning those properly. While dipping takes some time i though id keep moving, so i start at the front to do the front brakes and put new seals and oil in the shocks. The PO did advise he replaced the front forks, he had a brief conversation with a kangaroo coming out of a corner. i assumed they would be the type/model forks etc though I did notice the different caps. He did give me a bag of spares/ bits, old triple tree, some outer tubes, cylinders, springs, homemade short metal spacers, the original caps, and what think are the long spacers. NOTE: Australia had different forks compared to the US model 51100-49830 & 51100-49840 - compared to 51100-49810 7 51104-4900, also different mainspring, inner cylinder , spacer - everything else is the noted in the parts catalogue )... but i what i need to know is what forks etc are on the bike now

i can’t be sure the outer tubes on the bike are the original ones or form the new forks.. I guess the replacement forks ? Should i worry? the difference i can see if only in shape of the front fender lug/ attachment, they appear to be the same length and width as the spares, the stamped numbers on the inside where the fender fits are different
the outer tubes in the spares box have are stamped X4081 with 1 below in a circle....
the outer tubes on the bike are 3661E and an 8 below that in a circle - see pics

the inner tubes on the bike appear to be the 37mm diameter. are they long or short? i do not know i haven't removed them yet

I’m not sure whether is worth trying to use the old air caps ? for the original look or leave it also, considering those caps seem to have an adjustable thingo inside that presses on a washer than compresses the springs, it might cause much more work to try and go back to the old caps ;-)the ones on there now look to be adjustable for pre loading the springs see pics








the main springs in the inner tube are much longer - see pic so what do i do can anyone ID the springs, is there a stamp somewhere??


the outer tubes what are they off?




not on bike on bike




any suggestions on what i should do - im not concerned about being 100% original, though i like the look of the air caps, safety and function are more important to me.

Sorry for the long post , hopefully there is enough info there for you all to provide some feedback, thank you

cheers
grant

[angrypants]

1980 gs1000g perhaps ? be trawling through the fiche (pun intended) i aussie delivery had a similar cap and same style of axle holder, doesn't have that washer though more of a cup that presses on the spring??

[Grimly]

The European market, and possibly the Aussie market by the looks of it, had the adjustable pre-load on the fork tops of the GS850G and the GS1000G.
Not sure what your bike is currently fitted with - I take it you have the forks with the pre-load caps fitted.
You'll find, as I did, that the caps don't swap over, they're just enough different to not swap, which is annoying. The way to get air forks is to fit the air fork legs, which are bent, I assume.
I'd also recommend against the air caps anyway, as I tried them and found them to be a pain in the arris. Nice ride, but a bugger to keep airtight.
I ended up making my own pre-load caps which work quite well.

[angrypants]

thanks Grimly, the air caps do screw in but of course they wont preload the shocks much if at all .. the guy i bought it off was a very tall and large fellow , so maybe i wouldn't need the same preload. will do the sag readings etc and adjust. that is not so scary

i guess ive over reacted lol.. now ive thought about it my concern is ; are the forks too long or too short, i'm struggling to find any info on how long they should be on a gs1000ec from the top of the inner tube to the bottom of the axle.
anyone out there with a 78 ec able to measure that for me ? i can always have a bit poking out the top of the triple tree if too long...not much though as it will hit the flat bars ... if too short them i could be in trouble
thanks

grant

[Grimly]

thanks Grimly, the air caps do screw in but of course they wont preload the shocks much if at all .t

Now that's interesting. On mine, which was originally fitted with factory forks as an 850G, the preload caps will not screw in to the replacement fork legs I got from a 79 GS1000C. That's why I experimented with keeping the air caps, and ended up making my own preload caps out of a pair of the air caps.
The difference in leg length is around 19mm - the 1000C legs are shorter than the 850G. That was probably done by Suzuki to give the more touring-oriented G a bit of extra suspension travel.
The lower legs (sliders) are swappable between them.
The setup I have now is - GS1000C (single disc) stanchions that were spotless, GS1000 (dual disc) lowers of very low mileage and no wear internally, DIY preload caps, and GS1100E(S) springs fitted a couple of months ago. There's also a Technofix fork brace and a GS1100E mudguard which already had a fairly substantial brace underneath it. It actually steers quite well now.

[angrypants]

Now that's interesting. On mine, which was originally fitted with factory forks as an 850G, the preload caps will not screw in to the replacement fork legs I got from a 79 GS1000C. That's why I experimented with keeping the air caps, and ended up making my own preload caps out of a pair of the air caps.
The difference in leg length is around 19mm - the 1000C legs are shorter than the 850G. That was probably done by Suzuki to give the more touring-oriented G a bit of extra suspension travel.
The lower legs (sliders) are swappable between them.
The setup I have now is - GS1000C (single disc) stanchions that were spotless, GS1000 (dual disc) lowers of very low mileage and no wear internally, DIY preload caps, and GS1100E(S) springs fitted a couple of months ago. There's also a Technofix fork brace and a GS1100E mudguard which already had a fairly substantial brace underneath it. It actually steers quite well now.

Thanks for the reply -- im only guessing it was a 850g? looks like those caps also came on the 81+ 1000g in Australia too. So like a well customized set up? was it just convenience of what parts you had access to or where you trying for a specific outcome?

the caps, not 100% sure they screw all the way down, they screwed nearly all the way in before i stopped.. how do you know the fork/ leg length ? i'd like to check and see what exactly i have. if they were long should i just have the caps/ tube popping up a bit higher at the top to compensate ?

so other than trying to get correct ride height, what to do about fork oil ?) there is about 10ml diff 251ml v 241ml between the G and the E gs1000)

thanks

grant

[Grimly]

The outcome I was aiming for was just a set of leak-free working forks. When I bought the 1000 forks I was unaware of the shorter length, but it worked out ok. The trail is reduced a smidgen, which slightly lightens the steering and compensates for the extra weight of the fairing just right. It also lowers the bike by nearly an inch too, which definitely helps. The slight extra complication was tuning the centre stand. I cut the standard too short, and fitted a GS1000 stand.
All the GSxxxG forks I could find were pretty dinged and rusty, so I picked what I could find in good condition and made the best out of them.
The only way I can see to be sure of the leg length is to take them apart and measure.

[angrypants]

thanks mate,
i'll be taking them apart probably later today , im been sussing out photos in detail and assuming the out tubes i am comparing to are correct gs1000 as i have seen the G ones seem to have the 'longer / slower rise' to the guard mounting area, and the flairing to the dust seal end closer to the seal..(i.e) the i think G's are the ones above with the red mark .

I will measure.... but what do i compare the measurements against ? do you recall the measurement of the two, or just the difference in length. i dont have the bent tubes to compare (EDIT found some info on ebay sellers product detail /? might be close they say 612mm inner tube length for the G and 595mm for the 1000e


at present i've got the front master and calipers off for a full rebuild, i just missed 2 o rings in my parts order -- the parts book was wrong apparently, i needed 4 not 2. Luckily it seem the orings and seals i bought for the forks will fit either so all good there, ill get them done while waiting for the brake parts.

how much oil should i put in / wait until i measure and then see what i have.. or split the difference and go for 246ml , sonce i wont have air pressure a little more oil will be ok? or is it not worth worrying about eother way/

whats your thoughts?

thanks for assisting with this

grant

[Grimly]

As far as the oil quantity / level goes, I just put in 250ml per leg, by the book. I just used what I had at the time, an anonymous bottle of Spectro fork oil which didn't even have a viscosity rating on it, but was probably around SAE 10. I used it more to get rid of the bottle, rather than any real belief in it, as previously I'd always just used ATF, engine oil (5W40) or a mix of both.
However, nearly everyone else from tuners to spring makers recommend a level, so next time I'm renewing the seals or have the caps off I might top them up to what my spring maker (Wilbers) recommends, which iirc, is 140mm down from the top. Same for Hagon springs.

[LeT]

I agree that the level of oil measured from the top of the stanchion down to the top of the fluid, that's what counts. Do it with the springs out. Just work the stanchion in and out of the ally slider 5 to 10 times before measuring using a dipstick. That's to purge air bubbles out of the fluid. You've got two things to get right: the levels being the same both sides and that you have enough of a gap so the fork can do is full stroke without using up all the air gap, plus at least about 5cm IMHO because you'll have to allow for the springs displacing the oil when you put them in.

As a rule of thumb pour in the volume the manual says less about 30cc in both legs. Then measure oil height and adjust up the deeper to match. You could stop there or raise the levels more of you want a firmer ride. The smaller the air gap, the more resistance to movement from compressing the air. It's basically an air spring.

The grade of oil is a matter of preference and varies with ambient temperature. In the UK, I think 10w is a good choice for most folks, ok for 0 to 25 degrees Celsius.

[angrypants]

I agree that the level of oil measured from the top of the stanchion down to the top of the fluid, that's what counts. Do it with the springs out. Just work the stanchion in and out of the ally slider 5 to 10 times before measuring using a dipstick. That's to purge air bubbles out of the fluid. You've got two things to get right: the levels being the same both sides and that you have enough of a gap so the fork can do is full stroke without using up all the air gap, plus at least about 5cm IMHO because you'll have to allow for the springs displacing the oil when you put them in.

As a rule of thumb pour in the volume the manual says less about 30cc in both legs. Then measure oil height and adjust up the deeper to match. You could stop there or raise the levels more of you want a firmer ride. The smaller the air gap, the more resistance to movement from compressing the air. It's basically an air spring.

The grade of oil is a matter of preference and varies with ambient temperature. In the UK, I think 10w is a good choice for most folks, Ok for 0 to 25 degrees Celsius.

Thanks, for the advice, i appreciate it -- unfortunately work as popped its head up (how dare it lol) so haven't got to them yet. think tomorrow evening or Sunday.
cheers
gm

[angrypants]

waiting on a couple parts to get the job done - seems i miss at least one thing every time i order : ive got the forks in bits - missing an oring, carbs off waiting on 4 gaskets i missed , front calipers off - waiting on pads and orings for the pins/axles, front master off- needs a new reservoir + dust boot, rear calipers off, needs new pads and shims. So im rebuilding the cam chain tension and painting the calipers and master with VHT to keep at least some forward movement there