New Yamaha Suspension Set Up
Another site with information on Suspension setup with Pictures
Article taken from American Snowmobiler
Yamaha's New Suspenders (Article from American Snowmobiler Magazine)
Custom Setup For Yammie's
Front and Rear Suspension
Pre-season sales on Yamaha's new independent suspensions shot
beyond dealer expectations. But if you have been a loyal
Yamaha pilot for years, setting up and driving a trailing arm
front and long-travel rear suspension will be, let's say,
different, than TSS (Telescopic Strut Suspension) and short-travel
rear suspensions. Let's take a look at the do-it-yourself
adjustments for Yamaha's ProAction Plus, ProAction Plus X and
ProAction Plus SX suspensions.
Front Suspension Alignment
Positive and Negative Camber
Picture two vertical posts with the top ends slightly tipped
toward each other. This is negative camber, or vertical tip
in. Ends tipped away from each other indicate positive camber.
Parallel posts would indicate zero camber. Which works best
for the Yam aha front suspension? Zero to one-half degree
camber. Zero for the obvious reason - neutrality - for
neither aggressive, nor passive ski runner bite. One to one-half
degree positive camber forces a ski's outside edge down
slightly, creating aggressive rig ht and left-hand cornering
and sidehilling capabilities.
To make camber adjustments:
1. Rest the snowmobile on a flat, level (concrete or asphalt)surface.
2. Place an angle finder (carpenter's "bubble"
level) horizontally, at the bottom of the bellypan, and level
the machine by placing shims under the skis.
3. Next, place the angle finder horizontally on the trailing
arm's flat surface directly behind the spindle, and record
the amount of negative or positive camber.
4. Make the necessary adjustment by removing the radius rod
and turning the hiem joint in or out to achieve zero to one-half
degree positive camber. Repeat for the other side. Add Loc-Tite
to the hiem joint when re-installing the radius rods.
Toe-In, Toe-Out
Both posts are lying on a flat surface, parallel to each
other. Push in the front ends and you have toe-in. Push them
out and you have toe-out. The best setting here is 0 to 15mm
toe-out, at the most. Too much of either will result in
darting, pull and wa ndering. Toe-in, specifically, will
cause the snowmobile to push to the right or left. Large
amounts of toe-out will cause severe right and left pull. Ski-alignment
is easy to do, even for the novice rider.
To ensure your skis are evenly spaced for straight tracking:
1. With the snowmobile on a hard, flat surface and using the
handlebars, position the skis straight.
2. Connect the two ski hoops together with a bungee cord or
rope. Do not force the skis together; the rope or cord should
only take the slack away from the steering mechanism.
3. Lay a 10-foot pipe, straight edge or two-by-four along the
track edge with the length running next to the ski's inside
edge and extending beyond the ski hoop.
4. Using a tape measure, check the distance between the
straight edge and the ski's inside edge. Take these
measurements at the front and rear of the ski, approximately
10 inches in front of or back of the spindle, not at the
pivot point.
5. Following the owner's or service manual, adjust the
appropriate steering tie-rod until the ski's inside front and
rear edge measurements are evenly spaced or at a maximum 15mm
toe-out as measured against the straight-edge. Optimum
setting is 6 to 8mm t oe-out, as this will allow the skis to
scrub a hard-packed trail groove, and prevent the front from
hunting for a line of travel.
6. Repeat process on opposite ski, if needed.
7. If you notice that when the handlebar is straight, the
skis turn to the right or left (or if the skis are straight
and the handlebar is turned right or left), repeat steps 1-6
until both skis are pulled in or pushed out to the proper
distance.
Front Suspension Load
Yamaha uses a suspension term called set-in. Working with set-in,
you adjust front-end pre-load (ride height minus the amount
of suspension sag with rider) for your body weight and
handling needs. Depending on the model, set-in measurements
will be different. For example, Yamaha's Independent Front
Suspension offers nine inches of front travel on the XT and
XTC models, seven inches on the SX models and 6.7 inches on
the Mountain Max 600 and 700. Ya maha recommends set-in, with
driver weight, at 10 to 15 percent. If you were setting up an
XTC with 9 inches of travel, for example, 10 percent set-in
would be nine-tenths of an inch; 15 percent would be 1.35
inches set-in. Aggressive riders will want their suspension
dialed to 10 percent set-in or less. More conservative riders,
will want to extend beyond 10 percent and move to the 15
percent set-in level. Additionally, light riders (160 pounds
or less) may want a soft ride (more set-in), but big boys may
want little set-in. You will need the assistance of one other
person to make set-in adjustments:
1. With no rider on the sled,
lift the front of the snowmobile until the suspension is
fully extended, without lifting the skis off the ground. Then
gently and slowly set it back down.
2. Measure the distance between the front bumper and the
ground and record the distance.
3. With someone sitting on the seat, lift the front of the
snowmobile until the suspension is fully extended, without
lifting the skis off the ground, and then slowly and gently
set it back down.
4. Take a second bumper-to-ground measurement and record the
difference. This amount is your suspension set-in.
5. Following the owner's service manual, adjust the coil over
shock spring to set the pre-load at the appropriate setting.
Rear Suspension Rear Shock
Set-In
When setting up the rear suspension's set-in, or pre-load,
the set-in measurements for the rear suspension are the same
as for the front. Again, measurements are taken from the
bumper to ground.
1. After lifting the snowmobile's rear until the suspension
is fully extended, without lifting the track off the ground,
set the snowmobile back down slowly and gently.
2. Measure the distance from rear bumper to the ground and
record the measured distance.
3. With the driver sitting on the snowmobile, lift the
snowmobile's rear until the suspension is fully extended,
without lifting the track off the ground, and let the
snowmobile settle back down.
4. Measure rear bumper travel. If compression is more than 10
to 15 percent of total travel, make the necessary adjustment
to increase the pre-load. Adjustments can be made up to 15
percent of the total rear-travel distance.
5. Make the pre-load adjustment by changing the rear shock's
coil-over spring pre-load. ProAction Plus X and SX
suspensions use nuts rather than the cam used on the
ProAction Plus. The nuts provide a wider adjustment range.
Rear Shock Adjustment
Adjustments are made first on the rear shock's three-position
linkage. Repositioning the shock on the linkage will change
the shock's geometry. If the shock is moved to a lower
linkage setting the shock will act stiffer. The opposite is
true for a softer- acting shock.
Rear Traction Control Rod
The rear traction control rod couples the rear suspension's
front and rear shock and assists in weight transfer. Yamaha
delivers the snowmobiles to its dealers with the traction
control rod at an average setting for all riding conditions
and styles. The traction control rod is engineered with
adjustable top and bottom clearances. To increase weight
transfer, increase the rod's clearance at the sliding joint's
top side. This will also soften the rear suspension's overall
spring settings. Decreasing th e control rod's clearance at
the sliding joint's top side will reduce weight transfer,
make the suspension act stiffer and increase ski pressure.
Just remember: for more rock-back (weight transfer) lessen
the shock-to-shock coupling; for more ski pressure and less
rock-back, increase the coupling.
Front Torque Arm and
Limiter Strap
The front torque arm has two handling adjustments. Increasing
pre-load tension causes a stiffer-acting shock; decreasing
the pre-load delivers a softer feel. Increasing pre-load also
increases the weight transfer. Minimal pre-load means reduced
weight tra nsfer. As you may already know, lengthening the
limiter strap forces more weight to transfer to the rear,
shortening the limiter strap keeps weight planted on the skis.
When the limiter strap is increased, the rear suspension's
front shock pre-load must also be increased. By knowing your
needs, you can make an infinite number of adjustments, using
one or a combination of the traction control rod, rear shock
pre-load; front shock pre-load, and limiter strap.
BY MATT ALLRED
If you find your Yamaha SX or SRX to be too stiff even after adjusting the shocks and spring preload. Try putting a smaller spacer on the lower control rod. It's really easy to do. Put on the spacer that is used on the Vmax XT or XTC. I've put the 2.5mm ones on my SRX and found it will actually pull the ski's now! I'm going to try the 7.5mm and see if that will soften it up and keep the skis in the snow.
| SPACER THICKNESS (mm) | PART NUMBER |
| 2.5 (XTC) | 90202-16229-00 |
| 5.0 | 90202-16230-00 |
| 7.5 (XT) | 90202-16231-00 |
| 10.0 | 90202-16232-00 |
| 15.0 | 90202-16233-00 |
Check this site for more descriptions and diagrams. Also see Ronnies parts list
eMail me corey@cabler.com
