Fork Notes Wp

7/21/2019 Fork Notes Wp

1/18

WP 4357 & 4860 Fork Information

Introduction

The purpose of this document is to provide information on the location of sources for gathering

information on the forks and to put into one document operation and maintenance information withnotes on common problems and their solutions not documented elsewhere.

General Information

WP 4357 & 4!" #orks are fitted to $T% & usaberg machines from '""" onwards.

The 4357() *+, 4!"() produced between '""" and '""! are an open cartridge design and share

man- common components particularl- the damping components. The ma/or variation betweenthem is the fork tube diameters and the addition of a 3rdbush to the 4!"(s.

Parts Information

The $T% spare parts manuals are 0uite detailed in the descriptions and specifications on the parts

and variations in parts between -ear models and are a good source of information. These manualsare available from a number of the $T% dealers on1line.

Repair anuals

The repair manuals are available from WP )uspension and other web sites on1line. The manuals are

detailed with one or two e2ceptions such as disassembl- of the compression valve ad/uster.

!peration anuals

The $T% owners manuals available from $T% on1line have information on fork ad/ustments and

routine maintenance.

!t"er sources of information

usaberg.org website has a ver- good page of information

httpwww.husaberg.orgwikiinde2.php#rontsuspension

Without the help of the usaberg.org site this document would not have been possible so all thanksto them for making the information available.


2/18

Fork #asics

Fork $en%t"

The 4357 & 4!" fork lengths var- from model to model. The forks fitted to the $T% )6 rangehave a length of 35 mm & '5 mm of travel. The fork length is set b- the length of the inner and

outer tubes in con/unction with the length of the damping tube and piston rod.

The length and travel of the forks can reduced b- changing the piston rod or fitting a spacer below

the rebound spring. The length of the rebound spring can also be changed for greater rebound travel.

Fork ra'el

#ork travel or stroke is also set b- the h-draulic stop. 8hanging the h-draulic stop to a different

length or fitting spacers above the h-draulic stop can ad/ust 9reduce: the stroke of the forks.

;n the 4357 forks up to element to the spring rate. The air chamber length can be ad/usted to suit

individual riders and riding conditions. When the air chamber or volume of air in the forks is toolow the forks will become harsh on smaller bumps and can suffer h-draulic lock before ma2imum

compression is reached.

The air chamber length commonl- called the =*ir ?ap> is the distance from the top of the fork

when full- compressed without springs to the oil level and varies from


3/18

)omponent ec"nical Information

Re*ound +al'e

There are 3 variations on the rebound valve and rebound needle common to both 4357 & 4!"

models. The individual part numbers dates of introduction and complete unit part numbers are

,00- ,00, ,003.05Bebound tap 4!".""'5 4!"."

1 Top edge of mm shaft for check valves & mid valve chamfered

1 Fength of shaft for rebound shims increased

+ote. Watch out for the !2 mm shims the- can be easil- lost on disassembl- & re assembl-

The !2 shims are used to increase or decrease the mid valve or rebound valve sections.*dding shims increases the mid valve area and removing them adds to the rebound valve.


4/18

)ompression +al'e

There are 3 variations on the compression valve and compression needle common to both 4357 &

4!" models. The individual part numbers dates of introduction and complete unit part numbersare

'""< '""' '""31"5

8ompression tap 4!".""'7 4!"."


5/18

Periodic aintenance 1c"edule

Gleed fork legs Begularl-

4""" kms or '"""" kms or

once a -ear ever- ' -ears

1tandard aintenance Work

8heck fork for leaks and function 6

8heck tightness triple clamps fork leg a2le nuts and screws 6

Gleed fork legs 68heck spoke tension and rim /oin 6

Recommended aintenance Work

8lean and grease steering head bearings and gasket elements 68omplete maintenance of fork 6

?rease steering head bearings 6

i%"tenin% or2ues

#olt 1ie etric Imperial "readlock

8ollar +ut front Wheel )pindle m

Grake 8aliper #ront m 2


6/18

Routine aintenance & (d/ustments

Fork (ir Pressure Release

Put the motorc-cle on a stand with the front wheel

lifted off the ground.

Foosen the breather screws a few turns in order to

relieve the pressure from the inside of the forks.

)(I! E2cessive pressure in the fork canbe the cause of oil leaks. Af the fork is leaking it isrecommended to open the breather plugs before

replacing the seals.

(d/ustin% )ompression ampin%

8ompression damping is ad/usted with screwsat the bottom of the fork legs. Turn the knob

clockwise to increase compression damping &

counterclockwise to reduce damping

(d/ustment Procedure

Turn ad/usting screw clockwise full-

Turn it back the number clicks re0uired

(d/ustin% Re*ound ampin%

Bebound damping is ad/usted with screws at

the top of the fork legs. Turn the knob

clockwise to increase rebound damping & anticlockwise to reduce damping

(d/ustment Procedure

Turn ad/usting screw clockwise full-Turn it back the number clicks re0uired

WP Model Adjustment Ranges

T-pe WP "5


7/18

)leanin% t"e ust Wipers

The dust wipers remove dust and coarse dirt

particles from the fork tubes.

,irt ma- also get in behind the wipers and candamage the fork seals

Cse a screwdriver to lever the dust wipers out ofthe outer tubes and slide them downward.

8lean dust wipers outer tubes and fork tubes

thoroughl- and oil them thoroughl- with

silicone spra- or engine oil.

Then push dust wipers into the outer tubes b-hand or with a seal driver.

ote

Bemoving the fork protectors makes cleaningeasier

)"an%in% t"e andle*ar Position

The handlebar position can be ad/usted b- '' mm.

The upper triple clamp 3 has ' bores


8/18

)"eck and (d/ust 1teerin% ead #earin%s

8heck steering head bearings for pla- periodicall-.Place the motorc-cle on stand with the front wheel

off the ground. olding the a2le mounts and tr- tomove the fork forward and backward.

Af there is an- movement in the forks read/ust thebearings.

To read/ust loosen the five pinch bolts ' of the top triple clamp and turn steering stem boltclockwise 3 until there is no more pla-. ,onIt tighten the steering stem bolt all the wa- otherwise

the bearings will be damaged. With a plastic hammer lightl- rap on the triple clamp to release

tension. Be1tighten the five pinch bolts to '" +m 9


9/18

(ssem*l & isassem*l Issues

Fork u*e (ssem*l & isassem*l

The WP %6%* maintenance manual refers to removal and assembl- of the rebound ad/uster rod

=with ;1Bing>. The pictures on both assembl- and disassembl- do not show an- ;1Bing and the

$T% parts manuals do not list an- ;1Bing. At is assumed the "1Bing was intended to center thead/ustment rod in the piston rod.

)ompression aps

The compression tap bod- is allo- and the


10/18

Inner Fork $e%s

#ork legs are known to leak and be difficult to unscrew from the a2le holders. *nal-sis shows dirt

is entering the screw threads from the top of the a2le holder.

The solution is to seal the non threaded section of the inner tube which is inside the a2le holder. Toprevent leaking use a small amount of h-draulic thread seal above the "1Bing.

An addition to the above it is possible for dirt to enter the thread area from the fork guard mounts.* small !mm plug of closed cell foam at the rear of the fork guard mounting holes will stop dirt

entering and also protect the lower fork legs from distortion if e2cessivel- long bolts are used on thefork guards.

Re*ound +al'e & Piston Rod

;n re assembl- put 3" millilitres of fork oil into the piston rod prior to inserting the reboundad/uster rod. This will assist in a number of wa-s

#irstl- it will assist in dissipating heat generated in movement of the forks.

)econdl- it will prevent rusting on the internal surface of the piston rod.Thirdl- it will lubricate the upper area of the rebound damping ad/uster.

Fastl- it will prevent an- baking of assembl- grease to the internal wall of the piston rod.


11/18

1tandard ools Re2uired


12/18

WP 1pecial ools

!uter u*e )lamp

*lternative

Timber Tube olders

54 57 mm

54 !" mm

T5"


13/18

#W F650G1 )on'ersion Information

1teerin% ead & :okes

The #!5"?) has '< mm offset in the -okes less than this offset is reported to reduce steering locksignificantl-. The $T% )6 & E68 models have '"mm offset -okes standard & the forward edge

of the upper -oke from these machines is straight and has 3 2 !mm threaded holes suitable for

mounting the #!5"?) ignition switch & steering lock.

The )6 lower -okes have threaded steering stop mountings on their upper edge which an be usedfor mounting both steering stops & the G%W =)plash ?uard> with a little ingenuit-

Fork $e% Positionin% in :okes

When 4357 forks & $T% )6 -okes are fitted to the #!5"?) steering head the shape of the forkuppers provides


14/18

1tandard WP (ir )"am*er $en%t"s

* sample of standard WP air chamber lengths for 4357 & 4!" forks are below

WP 4357

WP 4357 %achines Travel Preload *ir ?ap

2000 - 250/300/380 SX, MXC, EXC '5 !


15/18

,ia Part +o ,escription )tandard !4" *dv !4"*dv %od )td %-

+o '""' '""3 '""5 "' "3 #!5" #!5"

r! M"#$%ne &e%'$t ()'*+ 154 158 158 154 158 1,, 1,,

-%tted R%der &e%'$t ()'*+ 91 86 90

.ue &e%'$t (0,5L%tre*+ 21 21 18,5 21 21 12,5 12,5

Total Weight 175 179 176.75 266 265 279.75 189.75

Spr%n'* .%tted 044 044 046 05 05 048 048

reo"d (+ 4 5 5 5

% &e%'$t 5 5 5 5 5 5 5

A%r "p (+ 120 100 100 100 100

Reound/Cop C%#)er* M%d M%d

45 4!".""'5 Bebound Tap 9K )pring: X X

45 4!"."

4 4!".""!' 8heck Halve 2'4 ".< 4 4 4 3 3 3

8heck Halve 2'4 ".

5" 4"54."4"' )him !2

5" 4"54."4"5 )him !2


16/18

+otes

The f!5" shim stacks are a starting point onl- and should be varied according to rider weight

loaded machine weight and the t-pe of riding envisaged

E2ternal sub tanks can be considered to 0uickl- stiffen up the suspension for road use

The valving should be the same on both 4357 and 4!" forks as the damping components are

common the 4357(s however have a different air volume and so air gaps will change

Compreion Valve

!3 4!"."

7" 4!".""!< 8heck Halve 2'4 ".4 1 1 1 1 1 1 1

7< 4!".""47 8ompression Piston X X X X X X X

Halve )haft Fength 135 135

Halve Thickness 89 89

8heck Halve *rea Fength 2 2

8heck Halve =float> 16 16

)him )tack Fength *vailable 26 16

)tack )i@e 15 13 11 09 09 085 09

5" 4!".""!3 )him !2'4 ".< 6 6 5 2 2 2 2

5" 4"54."4"" )him !2

5" 4"54."4"< )him !2


17/18

#W Front Guard & orn ountin%

There are a number of options on the choice of front guard ranging from after market guards $T%

guard or the G%W guard. The G%W guard is 0uite heav- at ". kg.

The G%W guard is < to ' mm too wide to fit

into the $T% lower -oke. The choices are usinga little heat to seat the guard into the -oke or to

take a little out of the -oke & the guard.

The horn can be mounted from the spare bolt

position in the front of the guard.

%ount dimensions are " 2


18/18

#rem*o Front #rake )aliper

The Grembo front brake caliper on the #!5"?) and the $T% !4"5" are the same. At is a standard

''.5552 3'3" mm piston caliper with a caliper bracket specific to each of the machines.

The combined caliper and bracket are shown as one part +o on the G%W on1line fiche.

The G%W caliper can be re used with $T% caliper bracket !"

Fork Notes Wp

Documents

Transcript of Fork Notes Wp