Ohlins FG 670 User manual

Owners Manual
Öhlins Superbike Front Fork FG 670

Safety signals
Important information concerning safety is
distinguished in this manual by the
following notations:
This Safety alert symbol means: Caution!
Your safety is involved.
!WARNING!
Failure to follow warning instructions could
result in severe or fatal injury to anyone
working with, inspecting or using the sus-
pension, or to bystanders.
CAUTION!
Caution indicates that special precautions
must be taken to avoid damage to the
suspension.
NOTE!
This indicates information that is of impor-
tance with regard to procedures.
Introduction
All of Öhlins advanced suspension products
are adapted to the brand and model. This
means that length, travel spring action and
damping characteristics, are tested individ-
ually just for the motorcycle that you have
decided to fit with Öhlins suspension.
Before installation
Öhlins Racing AB can not be held respon-
sible for any damage whatsoever to sus-
pension or vehicle, or injury to persons, if
the instructions for fitting and maintenance
are not followed exactly. Similarly, the
warranty will become null and void if the
instructions are not adhered to.
!
!WARNING!
1. Installing a suspension, that is not ap-
proved by the vehicle manufacturer, may
affect the stability of your vehicle. Öhlins
Racing AB cannot be held responsible for
any personal injury or damage whatsoever
that may occur after fitting the suspension.
Contact an Öhlins dealer for advice.
2. Please study and make certain that you
fully understand all the mounting instructions
and the owner´s manuals before handling
this suspension kit. If you have any questions
regarding proper installation procedures,
contact an Öhlins dealer or.
3. The vehicle service manual must be
referred to when installing the Öhlins sus-
pension.
NOTE!
Öhlins products are subject to continual
improvement and development. Conse-
quently, although these instructions include
the most up-to-date information available
at the time of printing, there may be minor
differences between your suspension and
this manual. Please consult your Öhlins
dealer if you have any questions with re-
gard to the contents of the manual.
NOTE!
During storage and transportation, espe-
cial
ly at high ambient temperature, the oil
and grease used for assembling may run
out inside the packing and damage the ex-
panded polystyrene packing material. This
is not unusual and is in no way detrimental
to the suspension.
© Öhlins Racing AB.
All rights reserved.
Any reprinting or unauthorized use
without the written permission of
Öhlins Racing AB is prohibited.
Printed in Sweden.
2

Öhlins Front Fork FG 670
This Super Bike front fork is an improved
version of FG 570 with pressurised damp-
ing system. FG 670 is based on 6 years
experience from factory road racing. The
pressurised damping system improves the
front fork function at high frequency move-
ments. The immediate damping responses
improve the tyre feeling and also give more
possibilities for adjustments. Of course
the combination of spring and air-gap (oil
level*) still gives a possibility to adjust the
characteristic of the fork to suit different
tracks and riders.
For example a soft spring in combination
with a small air-gap (high oil level) gives a
more progressive action of the front forks.
NOTE!
Gas pressure should not be changed or
used as an alternative to adjust the damp-
ing.
For better understanding, please refer to
our oil level chart see page 17.
A telescopic front fork is depending on a
smooth friction-free action. Make sure your
front forks are serviced regularly and don’t
use strong solvents such as brake cleaner
to clean the front forks. This will dry out the
seals and cause friction.
Contents
Before installation
Öhlins front fork FG 670
Adjusters
Setting up your forks
Changing springs
Changing seals
Dismantling the forks
Assembly of the forks
Oil level adjustment
Troubleshooting
Guidelines
Individual adjustments
Technical information
Spare parts list
Service tools
*
Front fork 670 is equipped with an external reservoir, pressurized
with nitrogen. A dividing piston separates the oil from the gas.
3
...........................................................2
.................................................3
...........................................................................4
......................................................5
...........................................................6
...............................................................7
.....................................................8
..................................................12
......................................................17
............................................................18
.....................................................................19
.................................................20
...................................................22
.............................................................23
...............................................................26

Adjusters
Your Öhlins super bike front fork is pro-
vided with the following external adjusters:
• Spring pre-load adjuster
• Rebound damping adjuster.
• Two type of compression
damping adjuster:
- Reservoir valve adjuster in the
lower part of the fork leg.
- Main valve bleed circuit.
NOTE!
The rebound damping adjuster is located at
the top of the right hand fork leg. The Main
valve bleed circuit (compression adjuster) is
located at the top of the left hand fork leg.
Spring pre-load adjustment
Use a 14-mm wrench to turn the upper
adjustment screw. The adjustment range
is 0-18mm. On the adjustment screw one
turn will change 1mm in spring pre-load.
Recommended static sag is 25-30 mm.
Compression adjustment main valve.
Adjust the compression damping on the
adjustment screw positioned at the top of
the left hand fork leg. Use a hex key with
spherical head (use tool 794-01).
Adjustment range from closed valve
(clockwise) to maximum open valve
(counter clockwise) is 20 “clicks”. Recom-
mended adjustment “click”, from closed
position: See specification card.
Rebound adjustment
Adjust the rebound damping on the adjust-
ment screw positioned at the top centre of
the right hand fork leg. Use a hex key with
a spherical head (use tool 794-01).
Adjustment range from closed valve (clock-
wise) until maximum open valve (counter
clockwise) is 20 “clicks”. Recommended
adjustment “click”, from closed position:
See specification card.
Compression adjustment reservoir valve
(Base valve)
Adjust the compression damping (shaft
displacement) on the lower part of the fork
legs. Use a normal screwdriver. Adjustment
range from closed valve (clockwise) to
maximum open valve (counter clockwise)
is 20 “clicks”. Recommended adjustment
“clicks”, from closed position:
See specification card.
Top cap
Increase spring pre-load
Reduce spring pre-load
14 mm wrench
Spring pre-load adjustment
Compression adjustment
Left Hand Fork Leg
Tool 794-01
Clockwise turn
closes = increase
compression
damping
Counter clockwise
turn opens = reduce
compression damping
Rebound adjustment
Right Hand Fork Leg
Tool 794-01
Clockwise turn
closes = increase
rebound damping
Counter clockwise
turn opens = reduce
rebound damping
Compression adjusment reservoir valve (Base valve))
Clockwise turn closes =
increase compression damping
Counter clockwise turn opens =
reduce compression damping
Tool 794-01
4

Setting up your forks
Here are some basic guidelines, how to set
up your Öhlins front forks. However, you
must remember that the front forks are just
one part of your motorcycle and to get it to
work properly, the whole motorcycle has to
be set up according to your bikes manual.
1
Put your bike on a front stand and fit the
Öhlins front fork.
NOTE!
The lower triple clamp must not be tight-
ened to more than 12-15 Nm. This is also
important for the steering damper bracket,
when located around the upper front leg.
To high torque might deform the front fork
leg.
2
Set your initial pre-load of the spring, by
using a 14mm socket or wrench, until you
get a static sag of 25-30 mm. Each turn
gives 1mm in pre-load, maximum pre-load
is 18mm.
Setting the spring pre-load generally on
the bike
3
Pre-load on the spring/springs is very
important, since it affects the height of
the motorcycle and the fork angle. Con-
sequently, handling characteristics can be
changed, even negatively.
Proceed as follows (it will be much easier if
done by two persons):
1 Place the motorcycle on a stand.
2 Lift up the rear end to a fully extended upper
position.
3 Measure the distance, e.g. from the ower edge of
the rear mud guard or from a point marked by a
piece of tape, immediately above the rear whee
axle, to the wheel axle. (R1)
4 Make a similar measurement on the front axle, e.g.
from the bottom of the upper fork crown to the
front wheel axle. The fork must be fully
extended. (F1)
5 Allow the motorcycle (without rider) to apply load
on the springs and repeat the measuring proce-
dure. (R2, F2)
6 Then take the same measurements with the rider
and equipment on the motorcycle. It is important
that the rider has a correct riding posture, so that
the weight is balanced on the front and rear wheel
in the same way as when riding. (R3, F3)
4
The measurements may not differ from the
following sizes:
Without rider:
Rear: 10-20 mm (R1-R2)
Front: 20-30 mm (F1-F2)
With rider:
Rear: 25-40 mm (R1-R3)
Front: 35-50 mm (F1-F3)
Increase spring pre-load
Reduce spring pre-load
14 mm wrench
A-D. Bike on a stand E. Bike on the ground F. Bike with rider on
R1
F1
R2
F2
R3
F3
Spring pre-load adjustment
5

Changing springs
12
14 mm wrench
1.
Unload the spring pre-load completely
by turning the adjustment nut counter
clockwise as far as possible. Use a 14 mm
wrench or socket.
2.
Loosen the screws that hold the fork legs
in the upper triple clamps.
3.
Remove the Top nut assembly. Use tool
797-01.
4.
Remove the top nut assembly from the
piston shaft. Use a 14 mm wrench to the
top and a 19 mm wrench to hold the nut on
the lower side of the top nut.
5.
Remove the adjustment driver and the
spring. Use a wire with a hook and care-
fully pull out the preload tube.
6.
Check the oil level according to page 17.
NOTE!
Use Öhlins Front fork oil 1311-01 only.
7.
Refit the Pre-load tube. Install the new
spring and refit the adjustment driver.
8.
Refit the top nut assembly to the piston
shaft. Tighten the jam nut to 20 Nm.
9.
Refit the top nut into the fork leg, with
the front wheel off the ground (use tool
797-01). Tighten the upper triple clamps
and adjust the preload, compression and
rebound according to above instructions.
CAUTION!
The top nut should only be tightened by
hand into the fork leg.
Tool 797-01
19 mm wrench
14 mm wrench
8 9
Preload tube
Adjustment driver
Spring
5 6
Check the oil level
1305-01
Tool 797-01
CAUTION!
20 Nm
34
6
Tool 1765-03

1800
1st, Circlip
2nd, Seal
3rd, Washer
Changing seals
1.
Remove the fork legs from the motorcycle.
Put the fork legs in upright position for
about 5 minutes to allow the oil to settle.
2.
Fasten the fork leg in a vice. Use soft jaws.
3.
Carry out instructions 1 to 5 in “Changing
springs”, page 6.
4.
Drain the cylinder tube from oil.
5.
Remove the outer tube, clean the seal and
check the condition. If the seal is in good
condition apply some red grease (146-01)
to it. A damaged seal must be replaced!
6.
First remove the circlip, then the seal and
finally the washer.
7.
Apply a thin layer of Öhlins red grease
(146-01) to the washer and to the sealing
surfaces of the fork seal. Install the seal
and the washer in the outer tube. Fit the
circlip into the groove.
NOTE!
It is important to use the correct grease in
order to achieve optimum fork function.
8.
Apply some front fork oil (1311-01) to the
inner tube surface and carefully mount the
outer tube (slide it completely down).
!WARNING!
Be careful not to damage the fork seal!
9.
Repeat instructions 6 to 9 in “Changing
springs” on page 6. Refit the front fork.
2 4
5 6
7Circlip
Washer
Seal
NOTE!
!
WARNING!
8
7
Tire Lewer

Dismantling the Forks
1.
Remove the fork legs from the motorcycle.
Put the fork legs in upright position for
about 5 minutes to allow the oil to settle.
2.
Fasten the fork leg in a vice. Use soft jaws.
3.
Unload the spring pre-load completely
by turning the adjustment nut counter
clockwise as far as possible. Use a 14 mm
wrench or socket.
NOTE!
Do not use the pre-load adjuster to tighten
or loosen the top-nut assy.
4.
Loosen the top nut assembly. Use tool
797-04.
5.
Remove the top nut assembly from the
piston shaft. Use a 14 mm wrench to the
top and a 19 mm wrench to hold the nut on
the lower side of the top nut.
6.
Remove the adjustment driver and the
spring. Use a wire with a hook and care-
fully pull out the preload tube.
7.
Remove the screw and o-ring from the
reservoir end cap.
NOTE!
Before the gas pressure is relieved the
adjuster settings must be counted and
noted. Even check that the gas pressure is
correct. Follow that, the adjusters should
be set in a fully open position.
8.
Relieve the nitrogen gas by inserting an
injection needle into the reservoir end cap
through the rubber valve.
14 mm wrench
Tool 797-04
19 mm wrench
14 mm wrench
23
4 5
6 7
8
NOTE!
!
WARNING!
Preload tube
Adjustment driver
Spring
8

!WARNING!
Releasing high pressure gas from the front
fork can be hazardous. Do not perform any
kind of service until gas pressure is com-
pletely released.
9.
Remove the circlip.
10.
Use tool 720-03 to lift up the reservoir end
cap. Install the tool 720-02 into the gas
piston.
11.
Use tool 1797-04 and 1765-03 to unscrew
the seal head from the cartridge tube.
Remove the piston rod unit.
12.
Fasten the piston rod in a vice. Use soft
jaws (727-02). Remove the nut with a 13
mm wrench or socket. Remove the valve
from the piston rod.
Place all parts, including the shims, in their
correct position on the work bench. Clean
all parts thoroughly and dry with com-
pressed air.
NOTE!
The right hand fork leg is the rebound leg.
The left hand fork leg is the compression
leg.
910
11
Tool 1797-04 Piston rod unit
Seal head
12
Compression Valve LH-Leg
Rebound Valve RH-Leg
13 mm socket
Nut
Soft jaws
(727-02)
Notes
NOTE!
Tool 720-03
Tool 720-02
9
Tool 1765-03

13.
Remove the Piston holder. Use a 22 mm
wrench.
14.
Remove the Topout spring, the Sleeve, the
Spacer and the O-ring.
15.
Remove the Seal head. Check the O-ring
and the X-ring. Change them if necessary.
16.
Remove the needle and change the O-ring
if necessary.
17.
Drain the cylinder tube from oil.
18.
Remove the gas piston in the reservoir, use
tool 720-02.
19.
Drain the reservoir from oil.
20.
Use a 17 mm wrench to unscrew the
complete compression valve at the bottom
of the fork.
21.
Remove the piston from the compres-
sion valve. Place the shims in their correct
position on the work bench. Clean all parts
thoroughly, change O-rings if necessary
and dry all parts with compressed air.
15 16
21
17
19
18
20
O-ring
Seal head
X-ring
O-ring
Rebound neendle
Notes
22 mm Wrench
13
Piston holder
Topout spring
Sleeve
Spacer
O-ring
14
10

22 23
Upper bushing
Lower bushing
Heat air gun
22.
Remove the outer tube, clean the seal and
check the condition. If the seal is in good
condition apply some red grease (146-01)
to it. A damaged seal must be replaced!
23.
First remove the circlip, then the seal and
finally the washer.
24.
Heat the tube where the bushings are posi-
tioned. Use a heat air gun.
25.
Put the outer tube standing up on a soft
suface, seal side facing down. Remove the
bushings by pushing them out. Use attach-
ment bar (1757-01) and dismantling sleeve
(1759-07) from the top nut side.
26.
Tap gently on the attachment bar with a
heavy hammer, until the bushings are free
and can be released from the seal side of
the outer tube.
27.
Check the innertube for damages, replace
if necessary. Use a heat gun to warm up
the fork bottom and tool 786-05 to un-
screw the inner tube of the fork leg.
28.
Check the reservoir tube for damages,
replace if necessary. Use tool 786-07 to
unscrew the reservoir tube.
24 25
Attachment bar
(1757-01)
Dismantling sleeve
(1759-07)
Rubber mat
26 27
Tool 786-07
1800
1st, Circlip
2nd, Seal
3rd, Washer
28
Tool 786-05
11

Assembly of the forks
1.
Use Tool 786-07 to refit the reservoir tube.
Tighten to 45 Nm.
2.
Use Tool 786-05 to refit the inner tube of
the fork leg. Tighten to 80 Nm.
3.
Put the outer tube standing up on a soft
surface, seal side up. Fit the bushings
from the seal side of the outer leg. Install
first the upper bushing then the lower one.
Use installing sleeve (1759-08), guide ring
(1758-04) and attachment bar (1757-01)
when installing the upper bushing. Ap-
ply Loctite 601 on the seat position of the
upper bushing, use a long brush. Tap the
attachment bar until it reaches the correct
position (stop against a shoulder).
4.
When the upper bushing is in position, the
lower bushing is to be installed the same
way. Apply some red grease (146-01) to
the bushing before installation.
5.
Apply a thin layer of Öhlins red grease
(146-01) to the washer and to the sealing
surfaces of the fork seal. Install the seal
and the washer in the outer tube. Fit the
circlip into the groove.
NOTE!
It is important to use the correct grease in
order to achieve optimum fork function.
6.
Install the piston and the shims on the
base valves. Tighten the 8 mm nut with
a torque of 7 Nm. Check the piston ring
and the O-rings for damages. Replace if
necessary.
Install the base valve assembly into the
valve housing. Tighten to 20 Nm.
12
Tool 786-07 Tool 786-05
4
3
Rubber mat
Loctite 601
Lower bushing
Upper bushing
Apply Red grease (146-01), No loctite!
Installing sleeve
(1759-08)
Attachment bar
(1757-02)
Guide ring
(1758-04)
Outer tube
Circlip
Washer
Seal
8 mm Nut,
7Nm
valve assembly,
20 Nm
12
Long brush
6
5

7.
Apply some front fork oil (1311-01) to the
inner tube surface and carefully mount the
outer tube (slide it completely down).
!WARNING!
Be careful not to damage the fork seal!
8.
Fill up with Öhlins front fork oil (1311-01) all
the way to the edge of the reservoir. Con-
tinue to fill until the oil level is the same in
both the reservoir and in the cylinder tube.
9.
Push the gas piston, with teflon band
and O-ring fitted, to the reservoir bottom
without allowing it to be pressed back over
the circlip groove, make sure that there is
no air between the piston and the oil. Use
tool 720-02.
Close the compression adjuster.
9
!
WARNING!
87
Tool 720-02
13
1675-01, Nut 1674-01, Washer Clamp Comp. Shim stack Comp. 1670-01, Piston 338-11, O-ring 530-22, Shims 1693-01, Spring 1669-01, Sleeve 1672-01, Collar 1658-01, End piece 438-02, O-ring 1242-09, Needle 1474-01, Spring 884-02 x 2, Ball 338-53, O-ring
1658-03, End piece
Basevalve RIGHT side (rebound leg)
Basevalve LEFT side (compression leg)
438-02, End piece
1672-01, Collar 1669-01, Sleeve 1693-01, Spring 530-22, Shims 338-11, O-ring 1670-01, Piston Shim stack Comp. Clamp Comp. 1674-01, Washer 1675-01, Nut 4803-11 (3 Nm , loctite 243)

10.
Grip the piston shaft with soft jaws 727-02.
Fit the O-ring on the adjustment needle.
Apply plenty of red grease on the O-ring so
that the needle slides easily into the piston
shaft.
11.
Check the X-ring and O-ring on the seal
head. Replace if necessary. Smear plenty
of white grease on the X-ring before you fit
it. Use tool 0715-01 to get the X-ring into
the right position.
10.
Wrap some teflon tape arond the thread
of the shaft to protect the seal and O-ring
from damages. Apply some red grease
(146-01) to the tape and the shaft end.
Mount the seal head and the O-ring.
11.
Use a brass wire brush to clean the piston
rod from tape. Mount Spacer, Sleeve, Top-
out spring and the Piston holder.
12.
Tighten the Piston holder to a torque of 15
Nm.
13.
Refit the Compression/Rebound valve. Use
the picture below to make it right. Tighten
the 8 mm nut with a torque of 7 Nm.
10 11
10 11
12 13
X-ring
O-ring
Piston holder
Topout spring
Sleeve
Spacer
REBOUND
LEG (RH)
COMPRESSION
LEG (LH)
8 mm Nut (7 Nm)
NOTE!
CAUTION!
530-22, Shims 525-18, Shims 1149-01, Wave Shim Stack (compression) 2061-03, Piston
Clamp (comp.)
1447-02, Piston ring Shim stack (rebound) Clamp (rebound) 1675-01, Nut
1654-09, Piston holder
1674-01, Washer
1654-09, Piston holder
Shim stack (compression) 1447-02, Pison ring 2061-03, Piston Shim stack (rebound) Clamp (rebound) 1674-01 2x, Washer 1675-01, Nut Clamp (comp.)
CAUTION!
14
15 Nm
Tool 0715-01
525-18, Shims 1674-01, Washer

CAUTION!
The Washers must be positioned correctly
(Notice that there is a difference between
the compression and the rebound valve).
Also make sure to fit the Wave washer
(1149-01) in the correct position (convex
side facing piston).
NOTE!
The right hand fork leg is the rebound leg.
The left hand fork leg is the compression
leg.
14.
Fit the Seal head tool and the Top-out
spring tool on the piston rod. Pull the Top-
out spring tool and, at the same time, push
the Seal head tool to contract the Top out
spring. Install tool 2810-01 on tool 1765-
03 to keep the contraction. Assemble the
complete piston rod into the cartridge tube
and tight it by hand (3-4 turns).
NOTE!
Make sure that the gas piston is pressed
down completely
15.
Tighten the Seal head to 20 Nm. Use Seal
head tool (1797-04 and 1765-03).
16.
Check the O-ring on the reservoir cap
assy. Replace if necessary. Apply some red
grease on the O-ring and push the reser-
voir cap assy into the chamber using tool
720-03.
17.
Fit the circlip. Make certain that it enters its
groove properly.
18.
Once again contract the top out spring
using tool 2810-01, tool 1765-03 and tool
1797-04
NOTE!
Nitrogen (N2) gas. Use pressure gauge
(1781-01)
14 Tool 1765-03
Tool 1797-04
Tool 2810-01
15 16
Tool 720-03
17
15
20 Nm
NOTE!
18

!WARNING!
Use of inflammable gas for pressurising
the soch absorber can be hazardous. Use
nitrogen gas (N2) only!
19.
Check the gas pressure stipulated in the
spec. card. Dip the needle of the gas tool
(1781-01) in red grease and insert the nee-
dle through the gas filler valve.
Charge with gas to the correct pressure,
according to the spec. card.
NOTE!
Ensure that there is no leakage of gas or
fluid.
20.
Screw the gas filler screw with O-ring.
Remove tool 2810-01 and tool 1797-04 to
release the top-out spring.
21.
Push tool 1765-03 to a stop and check the
oil level according to page 17.
NOTE!
Use Öhlins Front fork oil 1311-01 only.
22.
Refit the Pre-load tube. Install the spring
and refit the adjustment driver.
23
Refit the top nut assembly to the piston
shaft. Tighten the jam nut to 20 Nm.
24.
Refit the top nut into the fork leg (use tool
797-01). Adjust the preload, compression
and rebound.
CAUTION!
The top nut should only be tightened by
hand into the fork leg. The tightening force
of the triple clamp will hold it in locked
position.
24
Tool 797-01
CAUTION!
21
Check the oil level
1311-01
NOTE!
22
23
20 Nm
19
!
WARNING!
20
16
3 Nm
Tool 1765-03

Oil level adjustment
Compared with conventional type of front
forks, the upside down front forks are very
sensitive to variations in oil level. Therefore,
adjust the oil level with special care.
A change in the fork oil level will not affect
the spring force at the beginning of the fork
travel, but will have a great effect at the
end of the travel.
When the oil level is raised:
The air spring in the later half stage of
travel is stronger, and make the front forks
more progressive.
When the oil level is lowered:
The air spring of the travel is lessened, and
thus the front fork less progressive. The
oil level works most efficient at the end of
the fork travel. Air spring characteristics
shown, is a general card description to un-
derstand the difference when the oil level is
changed.
NOTE!
Adjust the oil level in mm according to the
figure with the fork leg fully compressed.
For the right oil-level, please see the speci-
fication card.
Air spring characteristics
Air inside the front fork works as a spring.
The graph at the bottom of the page shows
the spring force related to stroke when the
oil level is changed between 140 mm and
200 mm. Standard oil level is 180 mm.
Check the oil level
Öhlins front fork fluid 1311-01
17
Push to a stop,
use tool 1765-03

Troubleshooting
Below are a few examples of how to adjust
for the most common road holding prob-
lems in Road Racing driving.
1.
The front wheel “chatters” entering a
corner, the problem goes away, as soon as
you let the brakes off, or when you get on
the power.
• This is caused by the fact that the fork is working
too low in the travel and reaches the progressive,
hard part at the end of the travel.
• Put on more pre-load.
• Change to a harder spring.
• If a lot of stroke remains after riding, drop the oil
level. See oil level chart.
• Make sure the front forks have no friction.
• Rear ride height is to high, too much rear spring
pre-load.
• Lower the rear end by taking off pre-loadfrom rear
shock spring.
2.
The front wheel is jumping during the last
part of braking.
• If a lot of stroke remains, the oil level is too high.
Lower the oil level.
• If the fork is bottoming, put in harder springs and
keep the oil level.
3.
The front end feels unpredictable and un-
safe in the middle of the corner (between
braking and getting on power).
• Not enough rebound damping. Put on more
damping.
• Too much rebound damping. If it at the same time
feels harsh, take off some rebound damping.
• Too much compression damping. Also gives a
harsh feeling. Take off some compression
damping.
4.
The front end loses grip coming out of a
corner.
• Not enough rebound damping. Put on some more
rebound damping.
• Too much pre-load. Take off some pre-load.
• Rear end is too soft. Put on a harder rear spring.
• Front end is too high. Lower the front end by
pulling the fork legs through the triple clamps.
As mentioned in the beginning, the whole
bike setup affects the front forks. Try to
understand the feelings and work step by
step.
NOTE!
Our advice is to change only one thing at a
time and do everything step by step.
1
4
18

Guidelines
The settings on this pressurised Front
Fork are based on what currently is being
used in Moto GP racing, furthermore the
delivery spec is something we like to refer
to as a “balanced setting”. This means that
the pressure drop over the bottom valves
(base valves) and the top pistons (ø25mm)
are matched.
In order to avoid an unnecessary high in-
ternal pressure or risk of cavitation, please
use the following guide lines when adjust-
ing the front fork.
The FG 670 front fork can be divided into
two parts. One being the so-called
rebound leg (right leg), and one the
compression leg (left leg).
Start click position in this example:
Rebound (Top right) = 10 clicks open,
Rebound base (bottom right) = 16, never
adjust
Compression (top left) = 12
Compression base (bottom left) = 12
Rebound damping adjustment.
The rebound damping is adjusted on the
top of the right leg. Standard click position
is 10 clicks open from fully closed position.
The recommended range of adjustment
with this setting is 6-16 clicks open from
fully closed position.
Compression damping adjustment.
As said earlier the compression damp-
ing on this Front fork (FG 570) has been
checked for balance at the factory be-
fore delivery. In order not to change this
matched pressure balance between the
25mm valves (main piston) and the base
valves (bottom left and right leg), please
use the following guidelines.
By changing both the top and bottom
compression adjusters at the same time
you have a greater chance of keeping the
pressure balance between these adjusters
more constant.
For individual adjustments, see next page.
Compression adjustment
Left Hand Fork Leg
Tool 794-01
Clockwise turn
closes = increase
compression
damping
Counter clockwise
turn opens = reduce
compression damping
Rebound adjustment
Right Hand Fork Leg
Tool 794-01
Clockwise turn
closes = increase
rebound damping
Counter clockwise
turn opens = reduce
rebound damping
19
Compression adjusment reservoir valve (Base valve))
Clockwise turn closes =
increase compression damping
Counter clockwise turn opens =
reduce compression damping
Tool 794-01

Individual adjustments
Individual adjustments
Below you can find the recommended ad-
justment range for the top left compression
leg adjuster, with different positions on the
bottom base valve. From soft to hard:
Base 19 clicks, top 17-20 clicks
Base 16 clicks, top 14-18 clicks
Base 12 clicks, top 11-14 clicks
Base 10 clicks, top 10-12 clicks
Base valve:
The left bottom base valve can be ad-
justed from 8- 13 clicks, if top compression
is set at 12 clicks open.
Other tips and tricks
For on track adjustments and satisfying
your riders needs we could also look at the
adjuster from this angle:
1.
The compression damping from your left
base valve can be adjusted when you need
more compression damping, but you don’t
want the damping to react too quick! Let’s
say the rider needs more damping during
braking, then close the bottom adjuster 1-3
clicks since this adjustment will have time
to react during braking, but will allow the
front fork to go smoothly over bumps at
hard cornering.
2.
If the rider complains about lack of ”tire
feel” you can improve this by closing the
top left compression adjuster (2-3 clicks)
since these adjustments will give a quicker
response. This could also improve the
rider’s initial dive of the front fork when he
is applying the front brake NB! By closing
this adjuster too much, can also remove
some comfort and make the fork feel hard
and harsh.
Should the above instructions not be
enough or the standard setting somehow
not meeting the needs for you riders, then
please contact Öhlins racing AB Sweden
for setting information rather than attempt-
ing to modify the setting yourself. We have
a vast setting bank for this front fork with
balanced and matched settings to choose
from.
20
Compression adjustment
Left Hand Fork Leg
Tool 794-01
Clockwise turn
closes = increase
compression
damping
Counter clockwise
turn opens = reduce
compression damping
Rebound adjustment
Right Hand Fork Leg
Tool 794-01
Clockwise turn
closes = increase
rebound damping
Counter clockwise
turn opens = reduce
rebound damping
SOFT
HARD
Compression adjusment reservoir valve (Base valve))
Clockwise turn closes =
increase compression damping
Counter clockwise turn opens =
reduce compression damping
Tool 794-01