BRP ski-doo MACH Z 1000 SDI, Handbook

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SECTION 11 - COMPETITION PREPARATION
MMC2005-001_11A.FM
11-5
Cooling
• Install a pair of hydraulic quick couplers in the
coolant hoses at a convenient location on the
sled. Make a cooling cart using a cooler filled
with ice and several winds of copper tubing in-
side (or another type of heat exchanger) con-
nected to an electric pump and another set of
quick couplers. Connect your sled to this mobile
refrigerator between runs to circulate coolant
through the system and cool the engine down.
Cool the engine to the same temperature every
time so your runs are consistent.
Fore more drag racing and setup information con-
tact Racing Dept. by fax at (715) 847-6869, phone
(715) 848-4971.
SPEED RUNS
Generally, a speed run sled will be set up very sim-
ilar to an ice drag sled with the following differenc-
es.
• Some organizations do not allow lowering for
stock class sleds. Check your rules. Shorter
springs may be an option to try.
• Because holeshots are not important, engage-
ment speed does not have to be set at 5000
RPM. Top speed at the end of the course is the
only concern.
• Chaincase gearing can be set for high theoreti-
cal top speeds. Use the largest top and smallest
bottom sprocket available. This will keep the
belt low in the drive pulley which lowers the belt
and countershaft speed which makes the trans-
mission more efficient.
• As few studs as possible should be used. It
takes energy to push a stud into the ice and pull
it back out again. Since holeshots are not impor-
tant, use only enough studs to maintain control
at top speed.
• Use standard trail carbide runners with the
sharp edge worn down a bit. This way you will
have steering control without sacrificing speed.
• Run with a very short limiter strap and soft cen-
ter spring. This will reduce the track approach
angle which helps top speed.
OVAL RACING
Special Rules
• Rear of tunnel must be enclosed per specifica-
tions in the l.S.R. rulebook.
• Snowflap must be retained by chains or 3 mm
(1/8 in) diameter cable.
• Tail light AND brake light element must be on at
all times! Add a jumper wire inside the taillight
assembly.
• Any glass lenses must be taped over with clear
tape.
Front Suspension
• Relocate ski mount in spindle by drilling out the
predrilled hole 10 mm (.39 in) behind stock
mounting hole.
• Lower the ride height to the two inch minimum
travel requirement. Shorter springs are avail-
able.
• Valve shocks to light compression and medium
rebound
• Camber: Left = 0 degrees
Right = Negative 2 to 4 degrees
• Verify ski toe out, about 3 mm (1/8 in) at the
carbide edge.
• Steering ball joints should have as many jam
nuts added as will fit between the tie rod and
the ball joint. This helps prevent bending of the
threaded portion of the ball joint.
Center
• Use spring with soft preload and compression
and medium rebound.
Rear Suspension
• Lower the ride height to the 51 mm (2 in) mini-
mum travel requirement.
• Install a 4
th
idler wheel on the rear axle.
• Stiffer springs and firm preload may be required
to reduce weight transfer and help keep the skis
on the ice. If the handling is generally good but
the inside ski is lifting, increase the right rear
spring preload.
• Remove non guide clips and install taller track
guides on the right side of the track or use des-
ignated oval track.