GSX1400 Owners .org

Technically Speaking => Suspension => Topic started by: KoZi on Wednesday, 08 September 2021, 04:17 PM

Title: Suspension issue and infos - RaceTech + K-Tech
Post by: KoZi on Wednesday, 08 September 2021, 04:17 PM
Hello guys !

Quick topic about my experience with front suspension modyfication.
From two years I was using hyperpro progressive springs with hyperpro 20 oil. It Was better than OEM but still not enough for me... In fast corners and very dynamic ride fron wasn't as stiff as I want to.
So I talk with a guy in my contry who is servicing and modyficate suspension to sport. He told me that racetech have gold valve kits and to that we will put linear springs to my weight.
Kit arrived - Type 3 Gold Valve Combo Kit FMGV S2047C. We started to put in on and... it doesn't fit. We were in contact with guys from RaceTech a lot of messages and they told that - "Yes you are right we have mistake in our catalogue, this kit doesn't fit to GSX 1400" - BE AWARE !

https://racetech.com/ProductSearch/12/Suzuki/GSX1400/2002

Great... and now i was in dark point... what we can do, and finally we found the solution.
K-Tech are making front cartridge kit (to use with their new springs) - for special order.

https://store.ktechsuspension.com/front-fork-cartridges-20ids-suzuki-gsx1400-2001-2006-120-001-230-020.html?find=suzuki-gsx1400-2002-729222&product_list_limit=all

We orederd it and now I'm waiting for package - 2-3 weeks. I hope that all will fit.
In this topic I will describe rest of works and how suspension feels after chagnes.  :onya:
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: VladTepes on Thursday, 09 September 2021, 03:27 PM
Coo I;d like to upgrade my suspension one of these  days.
Watching.....
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: CROS on Monday, 01 September 2025, 05:03 PM
I have been informed that K-Tech no longer makes cartridge kits for the GSX1400. Leaving Nitron cartridge kits as the only remaining full cartridge I know of for the GSX1400.

Cheers CROS
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: lurch on Monday, 01 September 2025, 08:41 PM
I'm curious to hear about the K-Tech's. I personally went for Nitron TVT cartridges. The owner of the shop I bought them from is a lover of all things K-Tech so I was surprised he recommended Nitron. Unfortunately injury has kept me from riding much ever since.

I've never understood the Hyperpro "upgrade" for forks on any bike. For people who value handling over comfort a set of progressive springs and some excessively thick fork oil isn't the way to go.
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: Hooli on Monday, 01 September 2025, 08:45 PM
The one 14 I've tried with progressive springs worked well. Still comfy but when pushed a bit harder you felt it stiffen up as the suspension compressed. Might not be best for track etc but for the road speeds I'd do it worked well.

I did put normal 10w fork oil in that one when rebuilding the forks from the dangerous state a bike shop left them in.
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: SpongeBob on Tuesday, 02 September 2025, 02:05 AM
Quote from: CROS on Monday, 01 September  2025, 05:03 PMI have been informed that K-Tech no longer makes cartridge kits for the GSX1400. Leaving Nitron cartridge kits as the only remaining full cartridge I know of for the GSX1400.

Cheers CROS
I have Maxton's SD25-F3 cartridges installed for a few years, that come with (obviously) linear springs, rated to your weight, bike weight and riding expectations ("style").
Great piece of kit, and as opposed to K-tech at the time, they do not make installation by a "certified shop" mandatory. Comes with a comprehensive and detailed installation and settings manual.
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: CROS on Tuesday, 02 September 2025, 09:55 AM
Thanks SpongeBob - Looked at the website - they look good. Have bought Nitron 'race fitted' by local suspension expert.
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: grog on Tuesday, 02 September 2025, 05:44 PM
Just a question as i dont know. My forks are weight set, Wilbers springs,10w oil, all done for me by suspension bloke, work just fine.  What would i notice, find better with cartridge?
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: SpongeBob on Thursday, 04 September 2025, 02:10 AM
Quote from: grog on Tuesday, 02 September  2025, 05:44 PMJust a question as i dont know. My forks are weight set, Wilbers springs,10w oil, all done for me by suspension bloke, work just fine.  What would i notice, find better with cartridge?

Nicely put, politically correct question, @Grog :-) You managed to avoid the word 'bling' ;-)

I see that Wilbers do linear springs, so considering this together with the fact that your forks have been properly set up, most probably one won't notice big improvement with Maxton cartridges, as 14's OEM KYB forks look not bad, if not quite good, especially considering the whole bike construction,  having all necessary preload and compression/rebound damping adjusters and of a reasonable diameter. And linear springs as standard -- albeit a bit too soft.

Why I've installed Maxton SD25 cartridges, then?
Initially because I was looking for stiffer springs. I could simply change springs, for sure. But then:
I was very pleased with more recent technology with forks' damping, as experienced with the MVAgusta that shares my garage with the '14, that has completely separated damping elements for compression and rebound -- one leg handles compression, the other rebound. The two dampers are then different and each 'specialized' in it's duty, instead of do-it-all OEM dampers. That makes setup seemingly easier, and that proves to be efficient. The nice side effect is that you don't have to ensure that settings are identical on both legs, obviously, except for pre-load.
Finally, having a K2 with old style compression damping adjusters that are not (easily) serviceable, removable, etc. did make me nervous that one may seize at some point.

At the end of the day, I cannot really say there is a big difference, especially as I haven't tested the bike with OEM dampers back on it, or even tried another '14 since I switched dampers. But I can say that the front do behave nicely with those cartridges, and that any setup even slight change can be felt right away. For instance when I installed clip-ons, that then required to work on suspensions a bit.

Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: grog on Thursday, 04 September 2025, 02:24 PM
Thanks Spongey, great reply. When mine were done most i noticed was smoother over bumps, no dip on gear changes as it did stock.Maybe just my crappy gear changes😂 Im not changing just interested.When i first got 14, i tried every setting possible,wasted lots of time, annoyed me,shop settings one of the best mods done, have never touched since.Thanks Mate.
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: Andre on Thursday, 04 September 2025, 04:58 PM
Quote from: SpongeBob on Thursday, 04 September  2025, 02:10 AMI see that Wilbers do linear springs

As I have Wilbers springs in my 14, I can assure you that they only make progressive springs for the 14.

I don't use their oil. I use Liqui Moly 7.5W whith cSt 22 @ 40°C.

They work very well for me together with YSS 362 shocks.
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: grog on Thursday, 04 September 2025, 05:07 PM
Id forgotten Andre,what sort. Been a long time.I might even try 7.5, our roads are getting rougher.
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: Andre on Thursday, 04 September 2025, 05:11 PM
Quote from: grog on Thursday, 04 September  2025, 05:07 PMId forgotten Andre,what sort.

I don't understand what you mean by "what sort".
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: grog on Thursday, 04 September 2025, 05:17 PM
What sort, what kind meaning progressive or linear springs fitted.
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: Andre on Thursday, 04 September 2025, 05:19 PM
Progressive, as Wilbers makes NO LINEAR for the 14.

cSt values @ 40°C for Wilbers Fork oils:

2,5W    Wilbers TF Fork Oil    6,74
5W    Wilbers TF Fork Oil    22,50
7,5W    Wilbers TF Fork Oil    32,10
10W    Wilbers TF Fork Oil    50,10
15W    Wilbers TF Fork Oil    66,80
20W    Wilbers TF Fork Oil    99,40

From https://motoiservices.com/en/suspension-oil-equivalence-chart/
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: grog on Thursday, 04 September 2025, 05:41 PM
Thanks Andre, thats a really good chart. Champion as usual👍
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: Eric GSX1400K3 on Thursday, 04 September 2025, 05:51 PM
Interesting that the Wilbers 5W oil is closer to the LM7.5
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: grog on Thursday, 04 September 2025, 06:15 PM
Agree Eric, been thru all this b4 but never needed so never worried. The oils sure vary brand to brand. Think my old body telling me to go down , touch lighter. Will service forks, check with suspension bloke, he can fit just a touch lighter oil. Just a bit more compliance, not a lot.
Title: Re: Suspension issue and infos - RaceTech + K-Tech
Post by: Andre on Thursday, 04 September 2025, 06:20 PM
The (x)W designation of any suspension fluid brand is pulled out of the ass. There is no standard for this as in engine oil. You can't go by the (x)W labeling.  It is unfortunate that Wilbers (and many others) don't publish the data. Their current oils have a different name than the one in the above table. If you want to know what the current value is, contact them (or measure yourself).