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Offline Forks-by-Matt

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Fork revalve results and Nitron shock test
on: October 09, 2018, 03:13:20 PM
I ripped the forks apart and was not surprised at what I found. KYB/Kaw elected to use the 'tiny' orifice version of both the compression and rebound pistons. Worse the pop-off side of the rebound piston was heavily restricted by adding shims and impinging on it's ability to open up. I continue to be mystified why KYB persists in this stupidity. You'd think they might have learned a lesson or two from the FZ09 cock-up.

Replaced both pistons with KYB's 'large' hole version (from FZ/FJ09) and revalved all around. I should have put in 0.95kg/mm springs instead of 0.9 (I'm 250lbs)  and will probably need to add a 0.15 shim but for a 'best initial guess' the results were damn good. The 'whacks' caused by hitting square-edge has softened considerably. I did manage to bottom the forks out when I deliberately hit a 1.5" recessed manhole cover at about 40mph (hence the pending changes) but also the comp adjuster was set to full open.

The Nitron NTR1 (same as for Z900) slotted in easily and I resprung it for 115N/mm with an Ohlins spring but a 120 would have been more correct. The published rate charts are too soft by at least 1 step if not 2. I was having to put too much preload into the system and bike-sag was rather less than I wanted vis-a-vis rider sag. If you want a NTR2+ you'll absolutely need a hose-mount version.

https://www.dropbox.com/s/yllqahme3f69jw2/IMG_20181008_163040.jpg?dl=0
Last Edit: October 09, 2018, 03:20:52 PM by Forks-by-Matt

Offline Forks-by-Matt

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Re: Fork revalve results and Nitron shock test
Reply #1 on: October 09, 2018, 08:56:41 PM
Also it's mighty nice to have preload at the rear of the bike which makes changes trivial. The rebound and length are up by the engine but twisting the adjuster is very easy. Length adjust with a 22mm offset wrench is tight but not impossible.

Offline taximan62

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Re: Fork revalve results and Nitron shock test
Reply #2 on: October 09, 2018, 11:30:35 PM
So Matt do you do this for a living.  Will you  do forks for members and if so what will the cost be.  I am like you but closer oto 270lbs so your setup is very appealing to me.

Offline Forks-by-Matt

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Re: Fork revalve results and Nitron shock test
Reply #3 on: October 10, 2018, 12:18:09 AM
shipping forks back and forth from Canada is not exactly cheap. Best would be to ship you a set of pistons+valving and you take it to a local suspension guy to do the actual install. Some 'generic mechanics' can do it but unless you KNOW the one you have in mind is comfortable with suspension, I wouldn't count on them doing it correctly.

No, I don't do this FT - I'm a software/DevOps engineer in real life. Yes I do have people ship me their forks from all over CONUS but I'm a bit oversubscribed ATM.

Parts only (pistons+shims) would be like $60 (re-using FZ09 pistons - limited quantity) or if you want my custom-made pistons it'd be more like $120. Compare that to K-Tech's kit for $460. But to be fair the K-Tech kit includes cartridge bodies and replacement needles (3) whereas mine does not.

I'm a pseudo-dealer for K-Tech and Nitron and can pass on savings to forum members.
Last Edit: October 10, 2018, 12:28:06 AM by Forks-by-Matt

Offline silverjoe

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Re: Fork revalve results and Nitron shock test
Reply #4 on: December 09, 2019, 11:56:01 PM
Matt I used to work on bikes but that was many years ago. What tools besides the basic would I need  to install your pistons? Do you provide instructions?

Offline halbie

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Re: Fork revalve results and Nitron shock test
Reply #5 on: December 10, 2019, 07:08:30 AM
*Originally Posted by silverjoe [+]
Matt I used to work on bikes but that was many years ago. What tools besides the basic would I need  to install your pistons? Do you provide instructions?

He hasnít been on here for a long time.  I bought a Nitron R1 from him in July, but he was in and out of communication leading up to the delivery.

Offline silverjoe

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Re: Fork revalve results and Nitron shock test
Reply #6 on: December 10, 2019, 07:45:25 AM
Halbie thanks for the info