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BASIC BIKE SET UP
Before the first ride on a new or used
bike, some time spent on basic bike set up will help to ensure the best
results. New bike suspension, valving and spring rate are pre-selected
by the manufacturer in order to give the widest variety of riders
adequate performance under various conditions focusing on the bike’s
intended use.
The first step we recommend is to set
the rear suspension sag. Generally, the rear suspension sag should be
1/3 of the bike’s total rear wheel travel. For motocross bikes, 4”
or 100mm; off-road bikes with slightly less total suspension travel such
as KDX 200/220 or XR 250, should start with 90mm or 3-5/8”. My
neighbor insists 3.9" is perfect! Using a hammer and long punch or
drift, follow these instructions to set your rear spring sag:
THIS IS A TWO PERSON OPERATION
Put the bike on a stand with both
wheels off of the ground.
Measure from the center of the rear
axle to a fixed point on the back of the bike, such as a muffler bolt,
fender bolt, or a specific point on the rear fender.
Mark the fixed point for future
reference.
Take the bike off the stand and sit on
it in your normal riding position. Keep your feet on the ground with
just enough weight on your feet to balance the bike.
Have the other person measure from the
center of the axle to the previously marked fixed point.
Calculate rider sag by subtracting the
smaller from the larger measurement. This is easier when measurements
are taken in metric, since you don't have to deal with fractions.
Adjust as necessary to achieve the
recommended rider sag.
Note: The rider sag recommended above
should be used as a guide. A different sag level may be appropriate due
to differing riding styles, ability levels and riding conditions.
Always consult your manual. The
manufacturers do extensive testing, and while in the end their settings
might not be perfect for your usage or riding ability, the information
is still useful and valid.
Checking Clicker Settings
The next step is to check your clicker
settings. Most manufacturer recommendations are achieved by starting
with the clickers at full maximum (fully clockwise) and counting back to
the recommended number or clicker setting. See if the manufacturer or
your suspension tuner recommends 9 clicks out shock compression; turn
the clicker all the way clockwise until it stops and turn it back
counter clockwise 9 clicks. Check your manual and make sure the clickers
match the manufacturer’s recommendation or in the case of a used bike
that has already had suspension tuning by a professional, just check and
note where the clickers are set. Some savvy riders like to note right on
the shock and fork with an indelible marker the current clicker
settings. These can easily be removed with contact cleaner.
Next check the torque spec for your
front fork pinch bolts. Standard torque with 8mm pinch bolts should be
12-14 foot pounds. It is extremely important that the lower triple clamp
pinch bolts not be over tightened when the bike is equipped with
inverted forks, as it will cause binding and poor front fork
performance.
Take all possible care when riding a
used bike to be sure the bearings in the linkage, swing arm, steering
head and shock heim(s) are in good condition and well greased. A dry or
worn out bearing will cause poor suspension action, making it impossible
to properly evaluate your fork and shock set up.
Now gear up and take your first test
ride. Use this time to let new suspension units break in at least one to
three full hours. During this time, make some general observations about
your suspension performance but avoid making harsh judgments at this
point.
Suspension Testing and Adjustment:
The best way to evaluate and set up
your front fork and rear shock is to set up a small test track which
should include: small bumps, roots, rocks, turn entrance and exit chop,
a “G” load which will use up most of your suspension travel with a
steep exit lip (this will be helpful in determining rebound adjustment),
small and large hoopdedos, drop-offs or jump landings (that you feel
comfortable with per your riding level) and a log crossing (if
appropriate). I recommend the test track be a maximum 2-1/2 miles long
since you will use these obstacles as your control and should
continually utilize the exact same bumps so that your observations about
suspension adjustment and changes reflect the changes themselves, not
random differences in bumps encountered on a trail ride or an event.
Now start to circulate the track
making changes as needed. It’s okay to go back over and over again any
obstacle where you feel there is need for improvement. However, keep in
mind that the bike has to work everywhere. It must absorb the abrupt
square edge rocks and steer precisely as well as offer adequate
stability at higher speeds. So in the end, there may be a fair amount of
compromise to achieve the best package of settings to serve you well in
the real world! Remember to be realistic. You may be hitting the
obstacles aggressively when you’re riding the small test track but
sometimes a more plush, lighter setting will really pay in rocky and
rooty conditions when riding a 2 or 3 hour hare scramble or any long day
on your bike. I always tell riders that when doing suspension testing
and set up, to “trust your own judgment.” Don’t be influenced by
what other riders say or what you read in a magazine test article, the
conditions and rider levels may not represent your personal use.
Oversteer – Understeer: How it
relates to spring selection and suspension adjustment:
Oversteer is a term which describes
too quick steering. Some symptoms of this would be lack of stability at
higher speeds and a tendency for the front wheel to tuck under in loamy
or sandy turns, a situation known as “high side.”
Understeer is a term which describes
sluggish turning. Some symptoms would be difficulty to institute a turn
or a tendency for the motorcycle to always feel it wants to go over the
berm or stay to the outside of a corner.
Ideally, we want to achieve neutral
turning and balanced suspension. Lets say your testing shows your bike
has understeer. Some possible solutions for this would be:
A. Slide fork tubes up into the triple
clamps thus shifting weight distribution onto the front wheel thereby
reducing the rake angle and quickening steering.
B. Increase tension on rear shock
spring thus shifting weight distribution onto the front wheel.
These are two simple changes that can
dramatically alter the handling, steering and suspension performance of
your motorcycle. Some clues that might help you to determine your best
course of action are:
1. REAR SHOCK:
Compare the installed length of your
shock spring with the free length of the shock spring (the shock spring
will need to be removed for this). A general rule is that the installed
shock spring should have a maximum of 20mm of tension (preload).
Excessive preload will result in poor grip on small bumps like roots and
rocks. Another way to determine proper spring selection is to put the
bike on a stand, go through a similar measuring procedure as in setting
the sag, but this time take the second measurement with no rider, only
the bike’s weight. This measurement will determine “static sag.”
While the correct static sag might vary depending on terrain, I suggest
you should have a minimum of 1” static sag.
2. FRONT FORK:
Three ways you could alter steering by
the front fork adjustment are:
A. Lower/higher oil level.
B. Reduce/increase preload on front fork springs.
C. Quicker/slower front fork clicker settings.
Any of these or a combination of same
leaves you with good steering but excessive bottoming, you will have to
keep trying other options until you get the desired result.
What to do if your still not happy:
So far we have covered some basic set
up procedures and some possible adjustments that the average rider can
do. But if you are still left scratching your head as to what to do,
some indications that you need the help of a professional suspension
tuner might be:
1. Your weight is quite a bit above
average or below average (160-170 lbs). Unfortunately, if your weight
falls 30-40 lbs above or below this level, you probably will maximize
your results using a professional suspension tuner.
2. The riding conditions in your area
are extreme. Either severe low speed and rocky terrain such as in New
England or higher speed conditions such as the desert Southwest
conditions.
3. Your bike was designed for use
other than the use you intend it for. For example, a motocross bike
converted for enduro/off-road or trail riding.
When selecting a suspension tuner make
sure the tuner’s area of expertise suits your intended usage, talk to
other riders and once you have narrowed it down, speak directly with
some tuners you have chosen. Describe the type of obstacles you feel the
need to overcome. Remember he is the expert. He may ask you questions
that will help determine the best course of action. Be realistic when
discussing your use and riding level. I think that communication is the
most important component in your getting satisfaction from your
suspension tuner. In my experience I have found that any suspension
tuner that has lasted in this business is probably quite good and you
should base a lot of your decision on the feeling that the tuner you
spoke to understands your use, your riding level and has expertise
tuning the particular bike you own.
After you have determined with your
tuner what modifications are to be made, disassemble and pack up your
front forks and rear shock. Enclose a detailed written note to your
suspension tuner highlighting the particular concerns you have with your
suspension as well as details of your telephone conversation such as
procedures to be performed and parts you have agreed to change, your
weight, your riding level, your daytime phone number and the address you
want the parts shipped back to. Remember, your suspension tuner probably
talks to many prospective customers every day, so don’t assume
anything. Write it all down in your note.
Before you ship your parts make
absolutely sure there are no worn or dry bearings in your swing arm,
shock linkage or steering head. Your motorcycle will only work correctly
if all these items are in good repair and able to work harmoniously with
a properly tuned suspension. If you find any questionable parts,
immediately order the parts. Your satisfaction will be far greater if
you do the whole job right the first time.
Make sure you have a good shipping box
and heavy sealing tape; I like the fiberglass strapping tape. You also
might consider investing in an inexpensive gun case; they are foam-lined
and can be used again and again. However, both UPS and FEDEX charge $5
additional handling for non-corrugated packages - each direction. Tag
each suspension component with your name and address and phone number.
That way in the unlikely case that your box fails, you still will be
able to get your parts back.
Happy trails……
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