November 30th, 2015, 05:01 PM
Joined: Feb 2003
From: Escondido, Ca. USA
I Ride: 2005 Fe450,2001 Fx470,1997 Fx600
A snippet from the ATK Riders Forum. Good info about these forks. Thanks to "Rot Box" for posting this info:
Hopefully this will help someone down the road but so far from what I'm seeing WP made three versions of the inverted 40mm WP 4054 forks.
-The classic non-adjustable. Used on Husqvarna, KTM, Husaberg and ATK's throughout the mid-late 80's.
-The 'multi-adjuster' with rebound adjusters on the top and compression adjusters on the bottom outer portion (small red dial) of each leg. These are what I have on my 94.
-The 'top adjuster' which are the forks posted in the link above. These have compression adjusting in one leg and rebound in the other with the adjustment screws being on the top.
From what I can find the min/max fluid level is 160mm-120mm. both 10wt and 7.5 wt is recommended (depending on the manual) across the board for the 4054 forks.
I've been running mine at 118mm (130mm bottomed out on EVERYTHING) with 7wt oil. Unfortunately my compression adjusters are maxed out on the + setting. That said I really like the performance of these forks. Maybe it has to do with ATK's custom valving? I dunno I hear a lot of complaints about them being super harsh on the KTM boards and such.. harsh is not a word I'd use to describe mine.