BOMBARDIER 1996 Ski-doo MX Z440 Handbook page 202

Section ENGINE PREPARATION
04
Rotary valve timing should be set with the closing edge as close to specs as possible or slightly
higher.
NOTE : Refer to chart page.
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7. The engine should be pressure-tested for air leaks. It should hold 6 PSI for 6 minutes with no
more than a 1 PSI / min. loss.
8. Lube the rewind and inspect the rope for frays or cuts.
9. Oval racing must use taillight, brake light element on continuously (jumper from taillight wire
terminal to brake light terminal on taillight assembly), regulator, tachometer, and temperature
gauge.
10. Adjust ignition timing to the advanced limits. (.010" advance from spec.)
1995 AND 1996 IGNITION TIMING (BTDC) @ 6000 RpM
454 467
1.48 mm 2.08 mm
11. Synchronize carburetors so that they open precisely together and ensure that the cutaways of
the slides clear the inlet bores of the carburetors. After carb adjustment, adjust oil injection
pump.
12. On RAVE valve-equipped engines, check for free movement of the RAVE valve mechanism.
Check the passageways between valve piston and exhaust port for any carbon buildup.
Adjust RAVE preload. It is better to have the valve open a little earlier than later.
13. Use non resistor spark plugs—B9ES, B9EV, BIOES, BIOEV of heat range required.
14. Use premium fuel 93 octane.
NOTE : Be careful not to use too much deicer or gasohol fuels. The tech inspectors fuel
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meter doesn't particularly care for alcohol in your gasoline.
15. Tie wrap ignition wire connectors together.
16. Adjust carburetors for atmospheric conditions. (See carbu retion section.)
17. Break in a new engine before racing it. Performance can be gained by getting some run time on
the engine. Ten hours of break-in is recommended.
04-100
582 583
2.18 mm
(.086 in) (.069 in)
670 779
1.93 mm 2.11 mm
(.076 in) (.083 in)
599 494
2.18 mm 1.81 mm
(.071 in)
(.086 in)