Penske 8900 series User manual

1
Table of Contents Motorcycle Shocks
Installation .................................................................................................. 2
Notes ........................................................................................................... 3
Ride Height Adjustment ............................................................................ 4
Adjustment Recommendations ................................................................ 5
8900 Series Shock
Parts List ............................................................................................... 6
Specifications ........................................................................................ 7
8100 Series Compression Adjuster
Parts List ............................................................................................... 8
Operational Guide ................................................................................. 9
8660 Series Compression Adjuster
Parts List ............................................................................................... 10
Operational Guide ................................................................................. 11
8760 Series Compression Adjuster
Parts List ............................................................................................... 12
Operational Guide ................................................................................. 13
8900 Series Rebound Adjuster ................................................................. 14
Disassembly / Assembly Instructions ..................................................... 15
Suggested Maintenance ........................................................................... 16
Trouble Shooting ....................................................................................... 16
Valving
General Valving Characteristics ............................................................. 17
A Guide To Damper Tuning ................................................................... 18
Basic Start-up Procedure ...................................................................... 19
Valve Stacks .......................................................................................... 20
VDP and Digressive Valving Information Options .................................. 21
VDP 55mm Linear Base Shim .............................................................. 21
Preload Shim Spacers ........................................................................... 21
Pistons
Flow Rate Through Multiple Bleed Holes .............................................. 22
Piston Selection .................................................................................... 23
Linear Piston ......................................................................................... 24
Digressive Piston ................................................................................... 25
Velocity Dependent Piston (VDP) ......................................................... 26
Damping Adjustments ........................................................................... 28
Dyno Graph Overview ............................................................................... 30
Notes ........................................................................................................... 34
Table of Contents Page
Technical Manual
Motorcycle Shocks
(8900 Series)
REV: 3/27/01
#7
Main Office Midwest West
150 Franklin St. 12666 US-12 2499 S. Stockton St.
P.O. Box 1056 P.O. Box 666 Unit #1
Reading, PA 19603 Brooklyn, MI 49230 Lodi, CA 95240
[phone]  [phone] Fax [phone]  [phone] Fax [phone]  [phone] Fax
www.penskeshocks.com
Authorized Penske Racing Shocks Worldwide Distributors
PRS - AUSTRALIA PRS - CANADA PRS - U.K./EUROPE PRS - SOUTH AMERICA
NTT Racing Competition Tire Canada SPA Design Saenz Hnos.
(618) 8362-2113 [phone] 44 1 827 288 328 54 114 669-0956
(618) 8362-8811 Fax [phone] Fax [phone] Fax [phone] Fax

2
Your new Penske Racing Shock comes pre-adjusted at baseline settings. However, you must check
your rear sag before you race! This is very important for optimum performance.
Setting the Sag*
STEP 1
1) Without a rider on the bike,
have an assistant lift the
rear of the motorcycle until
the rear wheel is off the
ground slightly.
2) Using a tape measure,
measure the distance
between the axle center line
and a convenient location
on the rear subframe
(Figure 1).
3) Record this measurement as "A".
STEP 2
1) This step requires the rider
and two additional people.
2) One person should hold the
front of the motorcycle, straddling
the front tire.
3) Have the rider, wearing all of their gear, sit on the bike in a tuck position.
4) The third person should then measure the distance between the axle center line and a convenient
location on the rear subframe (same locations used in Step 1).
5) Record this measurement as "B".
STEP 3
1) Subtract "B" from "A". This number is your sag.
The amount of sag required varies from rider to rider and from track to track.
The sag should be between 7/8" and 1 1/6".
If the sag is greater than 1 1/6", preload the spring by turning the adjustable spring collar.
If the sag is less than 7/8", remove preload by turning the adjustable spring collar.
Installation
* BUELL APPLICATIONS: Use Buell spring sag recommendations.

3
Notes

4
Adjusting Rear Ride Height
1. Loosen the jam nut with 1" wrench.
2. Adjust the eyelet length.
(shorter or longer)
3. Tighten the jam nut.
Ride Height Affects
Going LONGER with rear shock length "eye to eye" will:
1. Raise the rear ride height.
2. Transfer weight from the rear wheel to the front wheel.
3. Make the front turn in quicker.
4. Reduce chain torque to the rear wheel.
Going SHORTER with rear shock length "eye to eye" will:
1. Lower the rear ride height.
2. Transfer more weight to the rear wheel.
3. Make the front turn in slower.
4. Increase chain torque to the rear wheel.
CAUTION!!!
DO NOT EXCEED THIS LENGTH
Ride Height Adjustment
å
.470" (12mm)
å

5
Road Race Track Tuning: Symptoms and Suggestions
A. Change only one adjustment at a time, and send the rider out for evaluation and feedback.
B. Take notes: Keep track of rider comments, lap times, tire conditions, and current
weather conditions.
C. Be patient, go back to your original settings if you get lost.
Symptom: Tuning List:
Harsh over bumps: 1. Go softer with low speed compression, 2 to 4 clicks at a time
(counter clockwise)
2. Go softer with high speed compression, 1 to 2 clicks at a time.
3. Increase rear spring sag, -1/2 to 1 turn at a time on spring perch.
4. Change to a softer spring rate.
5. Note: Too soft on compression can bring about a harsh feeling by
allowing too much shock travel.
Excessive wheel spin
exiting corners: 1. Repeat above steps.
2. Rebound can be too fast, allowing the rear to unload and spin
the tire. Use caution when changing rebound.
Wallowing exiting corner: 1. Stiffen low speed compression (clockwise).
2. Stiffen high speed compression, 1 to 2 clicks at a time.
3. Decrease rear spring sag.
4. Slow down rebound, 1 to 2 clicks at a time (clockwise).
5. Change to a stiffer spring rate.
Slow turn-in: 1. Raise fork legs in triple clamps
2. Increase rear eyelet length, 1/2 to 1 turn at a time.
Cannot exceed 12mm of thread exposed.
3. Soften fork compression
4. Increase front fork sag
5. Speed-up rear rebound.
Mid corner push - front: 1. Stiffen rear low speed compression
2. Slow down fork rebound
Adjustment Recommendations

6
8900 Series Shock Parts List
23 BU-10DU04 Bushing, DU .625 x .250
BR-37 Bumper (Top Out Clear)
24 OR-2220-B O-Ring, 2-220, Buna 70
25 SB-89 Shaft Bearing, 8900
26 OR-2114-V O-Ring, 2-114, Viton 75
27 SL-09 Shaft Wiper, .625 Poly (Blue)
28 OR-2312-B O-Ring, 2-312, Buna 70
29 SH-_____* Shaft, Adjustable, (10.0" - 24.0")
30 NT-04J Jam Nut, 5/8" - 18
31 MR-89 Metering Rod, 8900
32 BU-04-BZ Bushing, .200 Bronze
33 SC-08 Screw, Socket Set, 8-32 x 3/8"
34 SP-14 Spring, (A109)
35 BA-125-ST Ball, Steel 1/8"
36 SM-89 Shaft Mount, 8900, Adj. Platform
37 RS-89 Rebound Screw, 8900/Slotted
38 OR-2009-B O-Ring, 2-009, Buna 70 Duro
39 NT-06J Jam Nut, 5/8" - 20
40 EY-891775 Eyelet, 8900, RHA (MO-8T20)
EY-892175A Eyelet, 8900, RHA, Aluminum (MO-8T20)
EY-892175S Eyelet, 8900, RHA, Steel (MO-8T20)
EY-893050 Eyelet, 8900, RHA (MO-8T or MO-15T)
CL--89___* Clevis
41 SR-89225 Spring Retainer, 8900, 2.25", 55mm
42 RR-06 Wire Ring, .0625 Wire Diameter x 1.900
* Incomplete Part Number
PART
NO.
1 BD-81__* Body, Aluminum Coil-over (10.0" - 24.0")
2 RH-89225 Ride Height Adjuster, 8900, 2.25"
3 OR-2221-B O-Ring, 2-221, Buna 70
4 HO-87__* Hose (4" - 36" in 1" increments)
5 FT-__* Fitting, (45oor 90o), 1/8" NPT
6 BC-81__* Body Cap, 8100, (0o, 45o, 90o, 135o)
BC-89CL Body Cap, 8900 Clearance
7 MO-8T Mono Ball, .500 ID, Teflon
MO-8T20 Mono Ball, .500 x .875 OD
MO-15T Monoball, 15mm ID x 1.00 OD
8 RR-16 Retaining Ring, 1.025 Spiroloc
RR-10 Retaining Ring, .875 Spiroloc
9 RR-05 Retaining Ring, .250 Internal
10 JT-76HAT Jet, Top Hat
11 SP-15 Spring, (FF71)
12 JT-76POP Jet, Poppet
13 JT-RDHSNG Jet, Rebound, Straight Thru
14 NE-76 Needle
15 OR-2007-B O-Ring, 2-007, Buna 70
16 MR-8100 Metering Rod
17 NT-02R Ring Nut, 1/2" - 20
18 VS-__* Valve Stack
19 PB-55 Piston Band, 55mm
20 PI-____* Piston
21 OR-2028-B O-Ring, 2-028, Buna 70
22 VW-99 Top Out Plate, 1.375 x .504
ITEM
NO. DESCRIPTION
PART
NO.
ITEM
NO. DESCRIPTION

7
8900 Series Shock Specifications
Body Cap Clocking
__ 90oFitting __ 45oFitting
__ None
180o
135o
90o
45o
0o
Extended
Length
(shortest)
Stroke
Body Length
0o
315o
270o
225o
180o
45o
90o
135o
0o
315o
270o
225o
180o
45o
90o
135o
Reservoir Clocking
â
â
â
â
â â
__ 90oFitting __ 45oFitting
__ None
Type of Adjuster ________________
Eyelet Bushing
Total Width: ________ Bolt Diameter: ________
Body Cap Bushing
Total Width: ________ Bolt Diameter: ________

8
8100 Series Compression Adjuster Parts List
12 BA-250-ST Ball, Steel - 1/4"
13 SP-10 Spring, (TA2086)
14 HO-87__* Hose (4" - 36" in 1" increments)
AS-81UD Assembly, Update 8100 CD Adj with Knob
(Includes Items 4, 9-13, 15-24)
15 SC-02 Screw, Socket Set, 8/32" x 3/8"
16 KN-81 Knob, CD 8100
17 RR-02 Retaining Ring, .250 External
18 SC-08 Screw, Socket Set, 8-32 x 1/8"
19 SP-14 Spring, (A109)
20 BA-125-ST Ball, Steel - 1/8"
21 HG-81D Housing, CD 8100 Dished
22 OR-2006-B O-Ring, 2-006, Buna 70
23 DR-81 Drum, CD 8100
24 OR-2013-B O-Ring, 2-013, Buna 70
* Incomplete Part Number
PART
NO.
1 IU-22-S Air Valve, Port O-Ring, Steel
IU-04 Valve Core, 2000 psi
IU-06 Valve Cap, High Temperature
OR-2010 O-Ring, 2-010, Buna 70
2 RR-06 Wire Ring, .0625 Wire Diameter x 1.900
3 CP-81R Cap, 8100 Reservoir
4 OR-2221-B O-Ring, 2-221, Buna 70
5 PB-55 Piston Band, 55mm
6 PI-81R Piston, Reservoir 1.72 Diameter
7 OR-2323-M O-Ring, 2-323, Moly 70
8 RB-81__* Reservoir Body, 8100, (5.50" or 7.00")
9 SC-24 Screw, SHCS, 10-24 x 3/8"
10 VW-03 Washer, Valve, .635 x .015 x .191
11 DO-04 Dowel Pin, 3/32" x 3/4"
ITEM
NO. DESCRIPTION
PART
NO.
8100 Series CD Adjuster Option
Available in 5.5" and 7" Body Lengths
ITEM
NO. DESCRIPTION

9
8100 Series Compression Adjuster
The 8100 compression adjuster is located in the remote reservoir
assembly. The remote reservoir serves as an extension of the shock
absorbers vital elements: oil and nitrogen. The remote reservoir
theory allows for the use of increased volumes of oil and nitrogen
while allowing for smaller shock packaging. Increased nitrogen
volume is essential for consistent damping forces throughout a long
race and extreme conditions.
In the compression mode of the shock absorber, fluid is forced into
the remote reservoir in direct proportion to the area of the shaft
entering the shock body. As fluid enters the reservoir, it must pass
through the compression adjuster. Inside the compression adjuster is
the CD drum. The CD drum has (6) settings, numbered (1-6), with
number one setting (the largest hole) being full soft and number six
(the smallest hole) being full firm. As fluid is forced through the CD
drum (Figure 1), it is metered through one of the preassigned orifices
in the drum; it then enters the reservoir body, moving the floating
piston. The floating piston is designed to separate the fluid and
nitrogen, eliminating any chance of aeration.
In the event of high speed shaft velocities, fluid passing through the
hole in the CD drum could pack-up, causing an increase in damping
forces, due to the fact that fluid can no longer pass through the hole.
In this event, the fluid forces open the blow-off valve (Figure 2). The
blow-off valve makes a more linear damping curve.
Note: The remote compression adjuster is a fine tuning device for the
main valving located inside the shock absorber.
Figure 1
Figure 2
Low Speed High Speed

10
8660 Series Compression Adjuster Parts List
15 SP-16 Spring, (1460)
16 OR-2222-B O-Ring, 2-222, Buna 70
17 OR-2028-B O-Ring, 2-028, Buna 70
18 HG-76____* Housing, 8760, (Side Entry or Top Entry)
19 SP-14 Spring, (A109)
20 BA-125-ST Ball, Steel - 1/8"
21 OR-2013-B O-Ring, 2-013, Buna 70
22 SC-08 Screw, Socket Set, 8/32" x 1/8"
23 OR-2010-B O-Ring, 2-010, Buna 70
24 SH-86CD Shaft, CD High Speed
25 HO-87___* Hose (4" - 36" in 1" increments)
26 RB-76___* Reservoir Body, 8760, (4.00", 5.00" or 6.00")
27 PI-76 Piston, Floating 1.75 Diameter
28 OR-4222-B Quad Ring, 4-222, Buna 70
29 SL-87 Seal, Dowty
30 SC-18 Screw, SHCS, 4 - 40 x 1/4"
31 CP-76 Cap, Reservoir Port O-Ring
32 RR-06 Wire Ring, .0625 Wire Diameter x 1.900
33 OR-2010-B O-Ring, 2-010, Buna 70
34 IU-20-A Air Valve, Port O-Ring, Aluminum
IU-04 Valve Core, 2000 psi
IU-06 Valve Cap, High Temperature
* Incomplete Part Number
PART
NO.
1 RR-12 Retaining Ring, .343 External
2 CA-92 Cage, CD Clasp .343 Diameter
3 RR-12 Retaining Ring, .343 External
4 CA-90 Cage, CD Top Hat .343 Diameter
5 VW-91 Washer, Valve, 1.475 x .010
VW-88 Washer, Valve, 1.350 x .008
VW-66 Washer, Valve, 1.200 x .006
VW-44 Washer, Valve, 1.050 x .004
VW-28 Washer, Valve, .900 x .008
VW-30 Washer, Valve, .900 x .010
VW-38 Washer, Valve, .900 x .020
6 CA-76CD Cage, Compression Adjuster
7 SC-76INS Screw, Piston Insert
8 VW-70 Washer, Valve, 1.200 x .010
9 SC-06 Screw, SHCS, 1/4" -20 x 3/4"
10 VW-01-C Crush Washer, .25 ID, Copper
11 PI-76CD Piston, Compression Adjuster
12 OR-2013-B O-Ring, 2-013, Buna 70
13 DO-06 Dowel Pin, 1/16" x 3/8"
14 BA-187-ST Ball, Steel - 3/16"
ITEM
NO. DESCRIPTION
PART
NO.
8660 Series Adjuster Option
Available in 4", 5", and 6" Body Lengths
ITEM
NO. DESCRIPTION