Front Fork Spring Question?

[Rsk141]

Going Back Over Old Ground:



Front Forks



Stripped the forks down again for further investigation in to what can be done to improve / totally wreck front suspension.



made a few phone call been on the web, came up with some info:


500lbs bike + 200lbs rider   for road use 


Racetech spring calculator come out at Recommended Fork Spring Rate: 1.092 kg/mm = 10 kg /cm ish



Hagon Progressive are 5 Kg/cm rising to 7 Kg/cm as they are progressive



i was told that 10 Kg / cm is quite hard



!?



Also found out that my springs are over sized Progressive Springs coming in at a 515 mm as apposed to 460 mm



i think due to the fact it had a 17" front wheel and a 18" back wheel to jack up the front end a bit?


Replaced rear with 17" wheel so looks like i will need to chop a bit off or replace the springs but which rate?
or don't replace? dunno!?


Please advise what your springs are: Type / Rate / Length, this would be most helpful.


Any advise on this subject would be great.

[jaydee]

Might be better off getting in touch with a suspension specialist. A lot of tweeks going on there. I had some machining on parts done by a fella called Gareth who did a top class job in no time. I'm sure a call to him might get you on the right track.
Check out his website (phone no. on the top of page)

www.reactivesuspension.com/index.php

[oilyspanner]

If you fit the 1kg springs you would need to fit cartridge emulators too, even if you firmed it up a bit below this. The old damper rod forks are normally run on the soft side because the damper rod isn't able to flow sudden compressions at all well (would go solid too easily). The emulators work on the compression damping side and separate the compression and rebound, allowing some adjustability too. I saw some YSS emulators on e-bay recently, not sure if the 1100's were on there, but they would be okay if  they are, only £65 from memory. If you do anything that alters the front a good deal you'll need to alter the rear too.

The Hagon fork springs seem far too long from what you say, 20 mm or so isn't a problem - if  slightly long you can just play around with the pre-load until you get the right amount of sag. You would need to cut the spring or the spacer to make it work properly. I guess there's a leaflet that comes with the progressive springs.

All early GSXR's like extra rear ride height, a longer shock would be ideal. You could use an 18 inch rear rim to lift the rear, but it would only be around 15mm, which is better than nothing.

Setting suspension up can be a pain, but very worth it - as Jaydee says, you could get a local specialist do the work. Or you could service the forks, add decent progressive springs, or slightly firmer linear springs - emulators would be a good idea if you are able (they aren't that bad to fit). Check that the shock still has decent damping, set sag on it -or  for best results a replacement shock - loads of choices Bud !

Or fit later cartridge forks etc etc  . . .

[Rsk141]

Yeah totally get what your saying about Emulators
But that will increase the overall front end by the amount of the emulators around 17mm that PLUS the 460 springs length if this is correct takes it up to 480mm spring length which again leaves me with the issue of correct spring length / Rate. and if they are happier a bit nose down still no further forward.

old-skool-suzuki.proboards.com/thread/4385

as i say it a bit of a rethink just need some info on what people are using:

Rear seems sorted for now will Check it when i get it running

old-skool-suzuki.proboards.com/post/19027

[Rsk141]

it this post about the rear shock

old-skool-suzuki.proboards.com/post/19118

[oilyspanner]

You've been busy Rsk !
I haven't had 1st gen forks apart, so don't know the length of spacer etc Have you asked for details for fitment of the springs ? You can't fit springs that muck longer, the forks will be topped out.
If you can find out what the std spring rate is for the forks, you could then find some firmer linear springs - not too much, or the front and rear won't work together very well (I think you kept std spring). If you do that you could fit the emulators.

[Rsk141]

Thanks for your Input Oily

Done some measuring i've got 140mm from seal to bottom triple clamp
20mm static and 30mm Rider sag full travel is 70mm
just bouncing on the front brake will get better measure when on the road.

with no Comparison form people who have done this, I will have to suck it and see,

Got to Look at the damping now, Emulator would be the way to go, but we'll see what i can think up.

What this Space.

Thanks again!

[rusty]

Handy thread as I'm looking at changing the springs in my usd forks but have no idea what ones to get:-/

Saw the race tech springs on ebay with different weights and ive seen hyperpro progressive springs (twice the price...but does come with stickers)

Not sure which way to go:-/

[oilyspanner]

I had a thought Rsk, progressive springs are often a little longer because the initial section is a softer rate (I thought only 20ish mm longer)and is used up more than a linear. If you take measurements etc as you go along you won't go too far wrong. Even giving the forks a good service makes them feel a lot better, so you should get decent results.
Let us know how you get on - Oily