Penske 8900 series Technical Manual

Motorcycle shocks

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NTT Racing

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(618) 8362-8811 Fax

Table of Contents

Installation ..................................................................................................

Notes ...........................................................................................................

Ride Height Adjustment ............................................................................

Adjustment Recommendations ................................................................

8900 Series Shock

8100 Series Compression Adjuster

8660 Series Compression Adjuster

8760 Series Compression Adjuster

8900 Series Rebound Adjuster .................................................................

Disassembly / Assembly Instructions .....................................................

Suggested Maintenance ...........................................................................

Trouble Shooting .......................................................................................

Valving

Pistons

Dyno Graph Overview ...............................................................................

Notes ...........................................................................................................

REV: 3/27/01

Technical Manual

Motorcycle Shocks

(8900 Series)

Brooklyn, MI 49230

(517) 592-6681  (517) 592-3696 Fax

www.penskeshocks.com

Authorized Penske Racing Shocks Worldwide Distributors

PRS - CANADA

Competition Tire Canada

(905) 684-7418

(905) 684-1774 Fax

Parts List ...............................................................................................

Specifications ........................................................................................

Parts List ...............................................................................................

Operational Guide .................................................................................

Parts List ...............................................................................................

Operational Guide .................................................................................

Parts List ...............................................................................................

Operational Guide .................................................................................

General Valving Characteristics .............................................................

A Guide To Damper Tuning ...................................................................

Basic Start-up Procedure ......................................................................

Valve Stacks ..........................................................................................

VDP and Digressive Valving Information Options ..................................

VDP 55mm Linear Base Shim ..............................................................

Preload Shim Spacers ...........................................................................

Flow Rate Through Multiple Bleed Holes ..............................................

Piston Selection ....................................................................................

Linear Piston .........................................................................................

Digressive Piston ...................................................................................

Velocity Dependent Piston (VDP) .........................................................

Damping Adjustments ...........................................................................

Motorcycle Shocks

Midwest

12666 US-12

P.O. Box 666

PRS - U.K./EUROPE

SPA Design

44 1 827 288 328

44 1 827 260 528 Fax

West

2499 S. Stockton St.

Unit #1

Lodi, CA 95240

(209) 368-5040  (209) 368-5119 Fax

PRS - SOUTH AMERICA

Saenz Hnos.

54 114 669-0956

54 114 485-3028 Fax

Page

Table of Contents

Summary of Contents for Penske 8900 series

Page 1: Table Of Contents
Lodi, CA 95240 (610) 375-6180 • (610) 375-6190 Fax (517) 592-6681 • (517) 592-3696 Fax (209) 368-5040 • (209) 368-5119 Fax www.penskeshocks.com Authorized Penske Racing Shocks Worldwide Distributors PRS - AUSTRALIA PRS - CANADA PRS - U.K./EUROPE PRS - SOUTH AMERICA...
Page 2: Installation
Installation 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. * BUELL APPLICATIONS: Use Buell spring sag recommendations. Setting the Sag* STEP 1...
Page 3: Notes
Notes...
Page 4: Ride Height Adjustment
Ride Height Adjustment 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. CAUTION!!! .470" (12mm) DO NOT EXCEED THIS LENGTH Ride Height Affects Going LONGER with rear shock length "eye to eye" will: 1.
Page 5: Adjustment Recommendations
Adjustment Recommendations 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.
Page 6: 8900 Series Shock Parts List
8900 Series Shock Parts List PART PART ITEM ITEM DESCRIPTION DESCRIPTION * Incomplete Part Number...
Page 7: Specifications
8900 Series Shock Specifications Body Cap Clocking __ 90 Fitting __ 45 Fitting __ None Body Cap Bushing Total Width: ________ Bolt Diameter: ________ Type of Adjuster ________________ Body Length Extended Length (shortest) â Reservoir Clocking Stroke â â __ 90...
Page 8: 8100 Series Compression Adjuster Parts List
8100 Series Compression Adjuster Parts List PART ITEM PART ITEM DESCRIPTION DESCRIPTION 8100 Series CD Adjuster Option Available in 5.5" and 7" Body Lengths AS-81UD Assembly, Update 8100 CD Adj with Knob (Includes Items 4, 9-13, 15-24)
Page 9: Operational Guide
8100 Series Compression Adjuster Low Speed High Speed Figure 2 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.
Page 10: 8660 Series Compression Adjuster Parts List
8660 Series Compression Adjuster Parts List PART ITEM PART ITEM DESCRIPTION DESCRIPTION 8660 Series Adjuster Option Available in 4", 5", and 6" Body Lengths...
Page 11: Operational Guide
8660 Series Compression Adjuster Fixed Low Speed Bleed Circuit High Speed Flow Circuit Compression Adjuster COMPRESSION ADJUSTMENT In the state of low shaft velocities (i.e. corner entry, exit, and power down), oil is displaced within the damper in direct proportion to the volume of the shaft entering the body. The displaced fluid passes through the compres- sion adjuster where it is metered through a fixed, low speed bleed orifice.
Page 12: 8760 Series Compression Adjuster Parts List
8760 Series Compression Adjuster Parts List PART ITEM PART DESCRIPTION ITEM DESCRIPTION 8760 Series Adjuster Option Available in 4", 5", and 6" Body Lengths...
Page 13: Operational Guide
8760 Series Compression Adjuster LOW SPEED COMPRESSION ADJUSTMENT In the state of slow shaft movement (i.e., corner entry, exit, and power down), oil is displaced into the reservoir in direct propor- tion to the area of the shaft entering the shock body. The oil passes through the compression adjuster where it is metered through an adjustable needle and jet assembly.
Page 14: 8900 Series Rebound Adjuster
When installing any jet, apply a tiny drop of blue Loctite to the threads and torque to 120 in•lbs. The rebound adjuster screw on the 8900 Series shock absorber is located in the adjustable platform at the base of the main shaft.
Page 15: Disassembly / Assembly Instructions
1) IMPORTANT: Reservoir floating piston must be repositioned before the shaft is inserted into the shock body (refer to step #11). 2) Penske Suspension Fluid (Silkolene Pro RSF 5 wt.) is recommended. Use of alternate fluids may have an adverse effect the damper's internal sealing components. (i.e., o-rings)
Page 16: Suggested Maintenance
Suggested Maintenance PRE RACE ..................... Inspect for oil leakage. Check the nitrogen pressure. EVERY 30 HOURS OF TRACK TIME OR YEARLY ......Change oil. Replace the shaft seal o-ring, wiper, shaft bearing o-ring, reservoir cap o-ring and piston o-ring, floating piston quad ring, valve shims. Trouble Shooting LOSS OF NITROGEN PRESSURE ............
Page 17: General Valving Characteristics
General Valving Characteristics High Speed Low Speed* High Speed Rebound Compression and Rebound Compression The damping characteristics of your shock are determined by the compression and rebound valve stacks located on the main piston. The valve stacks are made up of a series of high quality shims, which are made to flex under the force of oil flowing through the piston ports and then return to their original state.
Page 18: A Guide To Damper Tuning
A Guide To Damper Tuning The ultimate purpose of a shock is to work together with the spring to keep the tire on the track. In compression (bump) to help control the movement of the wheel and in rebound to help absorb the stored energy of the compressed spring.
Page 19: Basic Start-Up Procedure
The following setup procedures are basic recommendations for reaching an initial starting point using double adjustable Penske Racing Shocks. This procedure is ideal for use on an open test schedule. A race weekend may not allow enough time. Start by making the compression adjustments as de- scribed below, until it feels right, then move to the rebound adjustments.
Page 20: Valve Stacks
Valving Constant Compression Valve Stack Rebound Valve Stack Constant When refering to shock valving, (example: A/B), (A) refers to the compression valve stack and (B) refers to the rebound valve stack. Valve Stacks Standard Digressive Valve Stack 1.350 O.D. 1.200 O.D. 1.050 O.D.
Page 21: Vdp And Digressive Valving Information Options
VDP and Digressive Valving Information Options 2 Notch 5 Notch 8 Notch 1.350 O.D. 1.350 O.D. 1.350 O.D. Part # Part # Part# .004 VW-2NX.004 .004 VW-5NX.004 .004 VW-8NX.004 .006 VW-2NX.006 .006 VW-5NX.006 .006 VW-8NX.006 .008 VW-2NX.008 .008 VW-5NX.008 .008 VW-8NX.008 Flow Rate Through Slotted Shims These flow rate values are dimensionless Equivalent...
Page 22: Flow Rate Through Multiple Bleed Holes
Flow Rate Through Multiple Bleed Holes Hole Diameter Hole Holes Holes Holes Holes Holes Holes Holes Holes 0.010 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 0.012 0.14 0.29 0.43 0.58 0.72 0.86 1.01 1.15 1.30 0.015 0.23 0.45 0.68 0.90 1.13...
Page 23: Piston Selection
Piston Selection This two stage piston combines the low shaft speed characteristics of a linear piston with the blow off characteristic of a digressive piston at higher shaft speeds. Both parts of the curve are independently tunable. PART NO. PART NO. DESCRIPTION DESCRIPTION...
Page 24: Linear Piston
Linear Piston Each piston face has a dished surface, to preload the valve shims flat against the piston face. The standard dishing is 1° on both the compression and rebound sides of the piston. By increasing the compression side dishing to 2°, the shims become increasingly preloaded, causing a slight delay in opening during compression movement.
Page 25: Digressive Piston
Digressive Piston Digressive Piston The “high flow” design incorporates larger ports on the face of the piston to increase the flow of oil throughout the shocks high speed action. When the shim stack opens, oil is “dumped” through the piston in large capacities. The increased flow of oil reduces the progressive damping characteristics of the linear side of the piston.
Page 26: Velocity Dependent Piston (Vdp)
Velocity Dependent Piston (VDP) O.D. Base Shim 01.235” for 55mm shocks 01.200” for 45mm shocks Compression Rebound Rebound Flow HIGH á HIGH Compression Flow This graph illustrates the way in which the two This graph illustrates the way in which the two different circuits operate on compression.
Page 27 Velocity Dependent Piston (VDP) The Velocity Dependent Piston (VDP) has the unique ability to be valved to duplicate the curves of either linear or digressive pistons. Varying the inner, outer and preload stacks in conjunction with various bleed combinations can duplicate virtually any type of force value. Also the velocity where forces come in or out can be varied by altering the shims and preload/bleed combinations.
Page 28: Damping Adjustments
Damping Adjustments There are three major ways in which you can vary the damping produced by the main piston: Shim stiffness, shim pre-load and the amount of bleed past the shims. These graphs help to visualize the way in which the damping is affected by each of these changes. Figure 1 shows the effect of changing the pre-load (on digressive or VDP pistons) or dish (on linear pistons).
Page 29 Damping Adjustments Figure 2 Figure 3...
Page 30: Dyno Graph Overview
Dyno Graph Overview +750 +600 +450 +300 Quadrant 1 Quadrant 2 +150 -150 Quadrant 4 Quadrant 3 -300 -450 -600 -750 -1.20 -1.00 -.80 -.60 -.40 -.20 +.20 +.40 +.60 +.80 +1.00 +1.20 Displacement (Inches) This section of the manual illustrates different valving combinations in the form of graphs. The graph shown is force vs.
Page 31 Dyno Graph Overview QUADRANT #1 QUADRANT #2 QUADRANT #3 QUADRANT #4 An easy way to help picture what is going on here is to relate the graph’s shape to what the dyno is doing to the shock. The dyno uses a scotch yoke system (shown above), where the motor turns a crank and the sliding yoke allows the main dyno shaft to make the up and down movement at the preset stroke.
Page 32 Penske Racing Shocks uses SPA Dynamometers because of its versatility and low speed metering and sample rates. Penske Shocks primarily uses the Force Average display, but SPA offers Decelerating CD/Accelerating RD and Accelerating CD/Decelerating RD viewing options for all its graph displays.
Page 33 Dyno Graph Overview Low Speed Bleed Bypass (nose) Bleed Chokes Off / Shims Activate (knee) Compression Rebound -100 -200 -300 -400 -500 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 Shaft Velocity (In/Sec) Note: Remember that low speed damping characteristics are controlled by bleed through the low speed adjuster and the bleed hole in the piston, not the valve stacks.
Page 34: Notes
Notes...