BRP ski-doo MACH Z 1000 SDI, Handbook

Page: 325 / 493

SECTION 06 - DRIVE SYSTEM
MMC2005-001_06A.FM
06-63
TRANSMISSION CALIBRATION
PROCEDURE
1. A new vehicle should be broken-in before fine
tuning the transmission. 200 — 300 miles will
allow things like bearings and the track to loos-
en-up. This will allow the sled to roll much freer
which may slightly change the clutch calibration.
2. Set up the chassis configuration (lowering, weight
transfer, traction).
3. Adjust the carburetor calibration to match the
condition of the day.
4. Pick the chain case ratio.
5. Define the driven pulley calibration. Stock is a
good starting point. Drag racers may consider
trying a larger cam angle. Use multi-angle cams
only for fine tuning after working with the drive
clutch.
6. Choose the drive belt (compound, length, width).
7. Define the TRA calibration.
• Start with the stock ramp in position #3.
• For most forms of racing, a higher engage-
ment RPM can be utilized. The better the
traction, the higher the engagement that can
be used. Most stock grass drag rules limit en-
gagement to 5500 RPM. That’s 5500 RPM on
the technical inspector’s tachometer and it
may not agree with your dash tachometer. If
in doubt, get the tech. man to verify your en-
gagement. The easiest way to raise engage-
ment is to use a spring with a higher start load
and a similar finish load. Remember, the stiffer
spring at start will also affect the shift curve
at 0 to 1/2 ratio.
• If the stiffer spring slowed down the shift at
low ratios, try more roller pin weight. The pin
weight will not change engagement much
but will shift faster. Utilize the threaded roller
pins to achieve pin weights in between the
hollow steel and solid steel pin.
• Fine tune the shift curve by trying different
adjuster positions. Use the lowest adjuster
number that still allows you to maintain RPM.
• Pin weight and ramp angle are interrelated,
but can be varied to achieve certain results.
A 16.5 gram pin and the adjuster set in #5
may produce the same full throttle RPM as a
14.5 gram pin with the adjuster set in #3, but
the lighter pin will be revving higher at part
throttle setting at low ratios. This may work
better for snowcross or woods racing where-
as the heavier pin may be better in a drag
race. Some ramp profiles will achieve better
top speed with the adjusters set in lower
numbers (1-4). If you are in position 5 or 6, try
a slightly lighter pin weight (1.5 to 2 grams)
and lower the adjuster position.
NOTE: Never use adjuster position #6 with the FZ
ramp. The tip of the ramp may touch the lever arm.
• If your shift curve is perfect but the engage-
ment is too low, a flat or notch can be ground
in the ramp right where the roller sits at neu-
tral position. This is a touchy procedure and
should only be attempted as a last resort. Be
prepared to scrap some ramps during the
learning procedure.
8. The best way to test clutching is with a set of
timing lights or side by side comparison with
a similar vehicle. Leave one machine as a base
line reference while tuning the test vehicle.
Don’t change things on both vehicles at the
same time or you won’t know if you are gain-
ing or losing. Also, only change one parameter
at time on your test vehicle so you know ex-
actly what results from the change.
9. For drag racers, try running the engine down
to several hundred RPM below the stated
power peak. When the exhaust is cold, the
peak power RPM drops. How much lower de-
pends on the engine type, exhaust type, jet-
ting and underhood temperature. Summer and
fall grass draggers should especially try lower
RPM.
10. This is where the winners become winners.
Test, test, test and then go test some more.
11. KEEP DETAILED NOTES OF ALL YOUR
TESTINGS!!!
No matter how good you think
your memory is, after you test your hundredth
combination, things can get overwhelming.