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Suspension
TUNING
Introduction
No area of machine adjustment is more critical than proper suspension tuning. An improperly tuned suspension will keep even the best rider from attaining the full benefit of his machine’s ability. Match the suspension to the rider and the course conditions.
WHILE TUNING THE SUSPENSION, KEEP THE
FOLLOWING IMPORTANT POINTS IN MIND:
•
If the machine is new, “break-in” the suspension with at least one hour of riding before making any setting evaluations or changes.
•
The three major factors which must be considered in suspension tuning are RIDER WEIGHT, RIDER
ABILITY, and TRACK CONDITIONS. Additional influences include the RIDER’S STYLE and PO-
SITIONING on the machine.
•
Before changing the suspension settings, test changing your riding posture or position to check whether it is the cause of the problem or not.
•
It is a wise practice to adjust the suspension to suit the rider’s strong points. If you are fast in the corners, adjust the suspension to allow fast cornering.
•
Make setting changes in small increments. A little bit goes a long way, and a setting is easily over adjusted.
•
The front and rear suspension should always be balanced; when the one is changed, the other one might need to be changed similarly.
•
When evaluating suspension performance, the rider must make every effort to ride consistently and to recognize the effects of his input. Such things as changes in rider position and increasing fatigue may lead to incorrect judgments about necessary adjustments.
•
When the proper settings have been determined for a particular track, they should be written down for reference when returning to the same track.
•
Lubricate the bearings in the swingarm and UNI
-TRAK® linkage after break-in and after every 3 races to prevent friction from affecting suspension performance.
Front Fork
Front Fork Air Pressure -
•
Adjust the front fork air pressure (see Front Suspension section).
Front Fork Oil Amount -
The fork oil amount in the fork tube is adjustable.
A change in the fork oil amount will not affect the air spring force much at the top of fork travel, but it will have a great effect at the bottom of it.
•
When the oil amount is raised, the air spring becomes more progressive, and the front fork action feels “harder” in the later stage of fork travel, near the bottom.
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When the oil amount is lowered, the air spring becomes less progressive, and the front fork action does not feel as “hard” in the later stage of fork travel.
Fork Oil Amount Effect on Fork Stroke
A. Weight
B. Fork Stroke
C. Increase Amount
D. Standard Oil Amount
E. Decrease Amount
Changing the fork oil amount works effectively at the end of fork travel. If fork bottoming is experienced, raise the fork oil amount by 0.5 mL (0.017
US oz.) each.
Front Fork Oil Amount Adjustment -
•
Adjust the front fork oil amount (see Front Suspension section).
Troubleshooting Improper Settings
Listed below are some symptoms of improper suspension settings and the most likely means of correcting them. The proper settings can be achieved by applying the information given in this chapter in a scientific, methodical manner. This does not mean, however, that you must be a scientist or trained technician to succeed. Simply take time to think about the changes you believe are necessary, check them against the symptoms and cures described here, make the changes in small increments, and take note of the changes and their effects.
Front Fork Improper Adjustment Symptoms -
Too Hard
Spring too stiff:
•
Rebound or compression damping improperly adjusted.
•
Fork air pressure high
•
Fork oil amount too high
Suspension stiffens at the end of the fork stroke:
•
Fork oil amount too high
•
Fork air pressure high
Spring OK, but suspension too hard:
•
Fork oil deteriorated
•
Fork air pressure high
Too Soft
The front fork dives excessively during braking and deceleration:
•
Fork oil amount too low
•
Fork air pressure low
•
Fork oil deteriorated
•
Rebound and/or compression damping improperly adjusted.
Rear Shock Absorber Improper Adjustment
Symptoms -
Too Hard
Suspension too stiff:
•
Compression damping too high
•
Spring too hard
Spring OK but suspension too hard:
•
Unbalance between the spring and the rebound damping (rebound damping too hard)
•
Spring preload too hard
Too Soft
Bottoming occurs on landing after a high jump
(otherwise OK):
•
Spring preload too soft or compression damping too soft
•
Spring too soft
•
Shock absorber oil deteriorated
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Determining the Proper Settings
Standard Settings
From the factory, the machine is set up for a medium-weight rider with intermediate riding ability.
Hence, if the actual rider weighs considerably more or less, or if his riding experience and ability are much above or below the intermediate level, it is likely that a few basic suspension adjustments will be necessary.
Basic Readjustment of the Suspension
Suspension Tuning According to Ground
Surface
Smooth
Terrain
Front Lower air pressure
Rear Softer spring
Rough Terrain
Front Higher air pressure
Rear Harder spring
Suspension Tuning According to Riding
Experience
Front
Lower air pressure with greater rebound damping
Beginner
Rear
Softer spring with greater rebound damping
Experienced
Rider
Front Higher air pressure
Rear Harder spring j
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Suspension Tuning According to Rider Weight
Front Higher air pressure
Heavy Rider
Rear Harder spring
Light Rider
Front Lower air pressure
Rear Softer spring
Suspension Tuning According the Type of
Course
Many Corners
Lower the front end slightly
(Increase the amount of fork tube protrusion above the steering stem head by 5 mm (0.20 in.).).
This accelerates steering and enhances turning ability.
Fast Course
Deep Dips or
Sandy Ground
Raise the front end slightly
(Decrease the amount of fork tube protrusion above the steering stem head by 5 mm
(0.20 in.).). This slows down steering and enhances stability at high speed.
Raise the front end slightly to gain stability.
Begin the actual on-track testing and evaluation after making these preliminary adjustments.
Bear in mind the following points when readjusting the suspension.
•
Always make changes in small steps.
•
The rider must be consistent in evaluating suspension performance.
•
A change in the front suspension might require one in the rear suspension, and vise versa.
Front and Rear Suspension Compatibility
Inspection
Use this procedure to determine if the suspension is balanced reasonably well.
•
Hold the motorcycle upright (remove the side stand.).
•
While standing next to the machine, lightly pull the brake lever, place one foot on the footpeg closest to you, and push down hard. If the motorcycle stays level as the suspension is compressed, the spring rates are well balanced.
•
Sit astride the motorcycle, take a riding posture and check that the machine is in a horizontal position. If one end drops noticeably more than the other, the front and rear are not compatible and must be readjusted to achieve a better balance.
Although this is one of the most effective adjustment procedures, suspension settings may vary depending on the conditions at the track and the rider’s preferences.
Front and Rear Suspension Troubleshooting
Front End Surges Downhill or During
Acceleration Out of Corner -
The front suspension is too soft.
•
Increase the compression damping or rebound damping.
•
Increase the air pressure.
•
Increase the fork oil amount.
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Front End “Knifes” or Oversteers in Turns
(Tends to Turn Inward) -
The front suspension is too soft.
•
Increase the compression damping or rebound damping.
•
Increase the fork oil amount.
NOTE
○
Heavier or expert riders may heighten the air pressure.
Front End Pushes or “Washes Out” in Turns
(Front Wheel Tends to Push Outward Rather than “Bite” in a Turn) -
The front suspension is too stiff.
•
Decrease the compression damping or rebound damping.
•
Decrease the air pressure.
•
Decrease the fork oil amount.
NOTE
○
Lighter or less experienced riders may lower the air pressure.
Front End Does Not Respond to Small Bumps in
Sweeping Turns -
The front suspension is too hard.
•
Decrease the compression damping or rebound damping.
•
Decrease the air pressure.
•
Decrease the fork oil amount.
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Rear End “Kicks” When Braking on Bumps -
The rear shock absorber rebound damping may be too low.
•
Increase the rebound damping.
Rear Tire Does Not “Hook Up” Out of Corners
(Lack of Traction Coming Out of Turns) -
The rear shock absorber may be too stiff.
•
Decrease the rear shock absorber spring preload.
•
Decrease the high speed/low speed compression damping.
•
Use a softer spring (lightweight rider only).
Fork Bottoms Off After a High-speed Jump (may be due to improper riding posture) -
The rebound damping is too soft or the spring is too hard.
•
•
Increase the rebound damping.
Decrease the rear shock absorber spring preload.
•
Decrease the compression damping.
Front and Rear Ends Bottom Off After a
High-speed Jump (harsh bottoming occurs once or twice per lap) -
The front suspension is too soft.
•
Increase the air pressure.
•
Increase the fork oil amount.
The rear suspension is too soft.
•
Increase the rear shock absorber spring preload or use a harder spring.
•
Increase the rear shock absorber high speed compression damping or use a harder spring.
NOTE
○
Check the front and rear suspension compatibility after making any adjustment.
•
Rear End Feels Soft at Small Jump -
Increase the spring preload up to maximum.
•
Increase the rear shock absorber low speed compression damping.
•
Rear End Feels Soft at Large Jump -
Increase the spring preload up to maximum.
•
Increase the rear shock absorber high speed compression damping.
Rear End Bottoms After 3 or 4 Successive
Jumps -
•
Decrease the rebound damping.
NOTE
○
The rear shock absorber behavior on this machine may mislead some riders.
○
The rear shock absorber bottoms (due to full stroke) when the spring and damping are overcome by the total weight of the machine and rider.
○
A bottoming sensation (even though the machine is actually not bottoming) may be caused by machine weight and the inability of the rider to overcome an overly stiff spring or excessive damping.
○
Observe the rear end jumps and try lowering the spring preload and damping if it does not approach bottoming.
Gearing
Selection of the Secondary Reduction Ratio
(Rear Sprocket)
Rear Sprocket Selection According to Course
Conditions
Fast Course Small sprocket
Many Curves or Hills
Sandy or Soft Ground
Large sprocket
•
If the course has long straight portions, the secondary reduction ratio should be reduced so that the machine speed can be increased.
•
If then the course has many corners or uphills or is wet, the secondary reduction ratio should be increased so that gear shifting and acceleration are smooth.
•
Since the speed must be changed depending on the ground condition on the day of the race, be sure to run through the circuit prior to a race and tune the machine accordingly.
•
If there is a long straight portion of the course on which the machine can be run at maximum speed, the machine should be set so that the maximum speed is developed toward the end of the straight course, but care should be taken not to over-rev the engine.
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•
Since it is difficult to set the machine so it is best suited for all portions of the circuit, determine which circuit portions will have the greatest effect on lap time, and tune the machine to these portions. Confirm your settings by recording lap times after each change. In this way the machine will deliver best performance for the entire circuit.
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Special Care According to Track
Conditions
•
In dry, dusty conditions (such a volcanic ash or fine powdery dust), special care must be given to keeping the air cleaner element clean.
•
When riding on wet, heavy clay, mud adheres to the tires and other parts of the vehicle. The mud can add significantly to the weight of the vehicle and therefore reduce performance. Take care to remove built-up mud from the tires and chassis after each ride, before drying occurs.
•
The engine works hardest in muddy conditions and the radiator can become clogged with mud.
Take care not to overheat the engine in these conditions. The engine also works very hard when riding in deep sand.
•
In muddy or sandy conditions, increase chain slack as the chain and sprockets will be packed with mud or sand, which reduces chain slack.
•
Check chain and sprocket wear frequently when riding in mud or sand, since wear is increased in these conditions.
•
Sticking muds or dusts on the front fork inner tube and rear shock absorber rod could damage to the oil seal, leading to an oil leak. Clean the sticking muds or dusts from the front fork inner tube and rear shock absorber rod after each ride.
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Key Features
- Powerful engine for exceptional performance
- Advanced suspension system for optimal handling
- Lightweight and high-performance design for racing and sporting use