• 4 Stroke Husqvarna Motorcycles Made In Austria - About 2014 & Newer
     FE = 4st Enduro & FC = 4st Cross

  • Hi everyone,

    As you all know, Coffee (Dean) passed away a couple of years ago. I am Dean's ex-wife's husband and happen to have spent my career in tech. Over the years, I occasionally helped Dean with various tech issues.

    When he passed, I worked with his kids to gather the necessary credentials to keep this site running. Since then (and for however long they worked with Coffee), Woodschick and Dirtdame have been maintaining the site and covering the costs. Without their hard work and financial support, CafeHusky would have been lost.

    Over the past couple of weeks, I’ve been working to migrate the site to a free cloud compute instance so that Woodschick and Dirtdame no longer have to fund it. At the same time, I’ve updated the site to a current version of XenForo (the discussion software it runs on). The previous version was outdated and no longer supported.

    Unfortunately, the new software version doesn’t support importing the old site’s styles, so for now, you’ll see the XenForo default style. This may change over time.

    Coffee didn’t document the work he did on the site, so I’ve been digging through the old setup to understand how everything was running. There may still be things I’ve missed. One known issue is that email functionality is not yet working on the new site, but I hope to resolve this over time.

    Thanks for your patience and support!

FE/FC 4CS FORK STICTION

Tetley

Tetley

Husqvarna
AA Class
I've been noticing recently my 2016 TE300 forks are suffering from really bad stiction. They compress a bit when putting the bike's sag weight on the forks, but when sitting down on the bike, they don't move at all. Also when riding on the tarmac, they are locked solid, and don't move at all unless hitting a pot hole.

This all became extremely apparrent when trying out a mates 2017 FE501 yesterday, the forks were super smooth with very little stiction. Even though this has Explor forks, the base parts are exactly the same as 4CS, ie top tubes, seals, bushes etc.

So first thing was to check fork alignment and installation, then checked to make sure nothing was bent, then removed the forks.
One side had huge amounts of preload on it, needing about 5KG more 'push' to get the fork moving, and both forks were very noisy and graunchy from 1/3 travel onwards.

I then removed the springs, and found both damper rods to be under 'spring loaded' extension, one side a lot more than the other, (which explains the preload). I pushed in the damper rods, and they got stiffer, and started noisily graunching and sticking towards full compression. The rods returned to fully extended under 'spring' return.

I then dropped the fork oil from the bottom chamber and put the base cap back on, now the damper rods moved easily with no 'spring' compresion, and sat fully compressed under gravity, all graunching and sticking now gone.

Next I reassembled the forks with no oil in, now they moved smoothly with no horrible noises.

I'm guessing there is air in the bottom chambers, which should/shouldn't be there, and an uneven amount per leg giving odd preload. As far as I know, all the air should be in the top chamber, and none at all in the bottom chambers?

The forks have had oil changes, one leg has new top and bottom tubes and seals (accident damaged) The dampers have never been apart or revalved, bushes are OEM, and I'm using Putoline 4wt oil.

Anyone shed any light on this please?
 
Everything is clean, straight and undamaged. The oil I dropped out of them was fairly clean too.
I've watched a lot of videos today, (Slavens Stillwell and WP etc) about 4CS, and found that when fully purged of air the damper rods do raise up under spring loading, as there is a spring loaded oil reservoir in the damper.
I'm starting to wonder whether Putoline oil is no good in these forks, and should try the very expensive proper WP oil, as was in them from new. Even when there is no oil in the damper, so siction in the damper is eliminated, the fork tube stiction is more than expected.
A freind remarked on how little stiction they had when new, and they only have 70 hours on them now.
 
Everything apart from the oil is OEM, so off to buy 5 Litres of WP oil tomorrow, and see what happens.

I originally posted this on the UK KTM forum, which is very busy, and has some suspension experts on there. Absolutely no one has replied to this! Normally a 4CS, or a jetting thread goes beserk, and runs to hundreds of posts.
 
Problem solved! :D
Putolene HPX R SAE4 oil is a load of shite in 4CS forks.
Just spent £91.08 on 5L of the proper WP oil, and forks are back to normal. Also serviced my mates XC300 frorks, and they all now feel the same and good.
Seems the Putolene has little lubricity, so causing sticking of the bushes, and juddering of the damper shims and oil reservoir pistons.
Surprised no one has had this before, as Putolene seems to be the easiest after market SAE4 oil out there. Shame Motorex don't do SAE4, as I've used Motorex for years on my other bikes with no problems.
 
bowser said:
I have successfully used Motorex 2.5W, 5W and 7.5W in my 4cs with no stiction issues
Click to expand...
How did using the 'wrong' weight of oil affect damping, or did you compensate by dialling the clickers in or out? I assume using an SAE 5 is very similar to the correct SAE 4?
 
accomodate with clickers.

You should compare suspension oils based off viscosity centistokes rather than weight. You can have the same weight oil but vastly different viscosities which effects damping. Far better off sticking with one oil that works for you and is easily available to you.
 
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