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Confused with progressive front springs GS1000E 1979

  • Thread starter Thread starter gs79
  • Start date Start date
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gs79

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Just purchased some Hyperpro progressive front fork springs for my 1979 Suzuki GS1000E. Have fitted new seals and filled to the correct level with fork oil. Come to put the new springs in with forks fully extended and the new springs are flush with the top of the fork tubes. The measurement of the spring is 49cm. According to the instructions you fit the original spacer, surely this cannot be correct as it would be impossible to compress the springs far enough to fit the spacer and screw on the end cap. Anyone have any ideas?
 
i have no dealing with the progressive springs. have you had the forks apart to fit the seals etc.?
have all the internals been refitted correctly so you have full extension on the fork legs?

are they DEFINATELY the correct springs for your bike?
 
Thanks for the reply, yep had the forks fully apart. Getting full extension, checking with the supplier all box marking suggests they fit the Suzuki GS1000E/S/G. Its odd but it is exactly 49cm from damper rod top to level with the fork top so you do have to compress to fit caps. This maybe a dumb question but why is the spacer there anyhow?
 
Preload, Wrestle'em in there, that's what I had to do with my Progressive springs. Goes better if you have a buddy to push while you turn...
 
Cannot understand why these springs are 490mm in length compared to the standard 421mm springs surely there should not be any difference in length should there.
 
Right, that's exactly what I said too. Remember you now have a progressive spring now and the old one after 30 years is not the same as it was when installed.
 
This could be normal:)
Don't forget that the std GS 1000 gets some preload from putting air under pressure in the forks.
The progressive springs work without air preload which means that the spring has to be compressed to fit it in the fork.
The question is how much?
I recently bought some RaceTech springs and they advise 15 to 20 mm preload.
This means that the spring must go down by that amount when the cap is tightened in place.
When you are done, you check the static sag i.e. by how much the bike goes down when on it's wheels with you on board.
It should be between 25 and 35 mm.
 
the sevice limit on the springs is 416mm so only 5mm shorter. i am surprised they still tell you to use the spacer.
clamp the fork leg in a vice with plenty of padding to stop scratching. install the spring and get a spanner on the top nut, push like hell and start turning the spanner when the threads look like they are close enough to catch
 
Thamk you for the replies guys. Just included a quick photo of the springs (apologise for the quality). This is with the forks fully extended and as you can see when the washer is put on top of the new spring it protrudes about 3mm above the top of the fork., so that when I screw on the caps it gives about 1 3/8 inch pre load. Does this sound right?
fork.jpg
 
When I installed mine I left the stock spacer in so I had about an inch and a quarter sticking out the top. When done and off the centerstand I had about 1 1/2" compression under static load versus about double that before. It started out a little stiff but I find it just about perfect now, it no longer bottoims out under heavy braking. I did however notice I needed new schocks to keep up with the front spring rate and balance the bike. Made a huge difference in the handling..

Cheers
 
Very impressive but I've been told there can be too much of a good thing.:eek: There should have been instructions included with your springs suggesting the recommended spacer length..
 
Unfortunately it does not mention anything at all about the spacer length. It just says fit the pre load bush
 
I really do not know if they are right for your bike.
I may have a solution for compressing them and tightening the cap.
!/2 inch drive socket extension with a 3/4 drive socket inverted and slipped up the extension one that you can get a really good grip on (deep-well).
Put your normal socket on the extension.
Push down force on the deep-well and tighten with other hand.
It can take a lot of force so be very careful you do not start to cross-thread.
I have used this technique on a few different bikes with great results.
 
Awaiting an email back from Holland from the manufacturers for their comments. Meanwhile I will probably fit the forks and check the static sag and go from there
 
gs79 said:
Unfortunately it does not mention anything at all about the spacer length. It just says fit the pre load bush
Click to expand...

Check the manufacturers website, might be some help there but I would put a spacer in there to preload the spring otherwise you will have too much static compression.
 
Most likely the instructions are in error. Assuming these springs are designed to work without air assist, then the springs should be roughly equal to the top of the extended legs before installing the caps. I'd try them with out any spacers then measure sag. Add a spacer as needed to get the proper amount of sag - I believe, about 25-30% with a rider sitting on the bike.
 
gs79 said:
Cannot understand why these springs are 490mm in length compared to the standard 421mm springs surely there should not be any difference in length should there.
Click to expand...
Did your stock setup have a spacer?

What was the total length of the spring (421mm) plus the spacer?

Any chance it's somewhere near the 490mm that you have now?

In other words, it probably hasn't changed much, just that it's all spring now, not spring and spacer.

The important thing to remember concerning 'preload': it is the amount of compression that you need to add to achieve the proper "sag" in the suspension.
"Sag" is the amount the suspension compresses from full extension to "ready-to-ride" height. You will need a helper to measure this, but check the length from the top of a fork tube to the bottom of the steering stem while the bike is on the centerstand and the forks are fully extended. Now have your helper measure the same area when you are on the bike, balanced on your tippy-toes, putting all of your weight on the bike. You want the suspension to compress about 20-25%. Most of our bikes have about 6 inches of fork travel, so that means 1 1/4 to 1 1/2 inches of "sag" is your target. If the bike drops more than that, add a spacer to get it back up. If it dropped 2 inches, add a 3/4 inch spacer, you will be close to that 1 1/4 inch figure.

By the way, you can do the same checks for the rear shocks to determine how much preload to add.

And, it is important to note that this assumes that you have the proper rate springs. Once you have your spring rates sorted out, it will be a simple matter of adjusting your fork oil viscosity to tune your damping, but that is for another thread.

.
 
Crankthat said:
I really do not know if they are right for your bike.
I may have a solution for compressing them and tightening the cap.
!/2 inch drive socket extension with a 3/4 drive socket inverted and slipped up the extension one that you can get a really good grip on (deep-well).
Put your normal socket on the extension.
Push down force on the deep-well and tighten with other hand.
It can take a lot of force so be very careful you do not start to cross-thread.
I have used this technique on a few different bikes with great results.
Click to expand...

they dont have a socket size nut on the fork tops, they are kind of oblong shape with the air valve screwed in. i would remove the air valve to prevent damage and you can only use a spanner to tighten them.
 
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