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Vintage ski-doo Timing Specs

Special thanks to Gilles, from Quebec, for sending this in to help others.
(For information only, always check the proper engine manual to be sure)

Some 1970-1979 Rotax Single and Twin Engine Ignition Timing Specs

Engine Model Direct Timing BTDC (1) Indirect Timing BTDC (1)
245 (1976)* 0.035-0.055 in. (0.90-1.40 mm) N/A
245 (1975)* 0.037-0.057 in. (0.95-1.45 mm) N/A
247 0.147-0.167 in. (3.73-4.23 mm) N/A (2)
248, 249 0.077-0.097 in. (1.97-2.47 mm) 0.800-0.100 in. (2.04-2.54 mm)
250 0.150-0.170 in. (3.81-4.31 mm) 0.150-0.160 in. (3.81-4.06 mm)
292 (1970-1971) 0.140-0.160 in. (3.55-4.06 mm) 0.195-0.221 in. (4.95-5.61 mm)
292, 302 (1972) 0.147-0.167 in. (3.73-4.23 mm) 0.195-0.215 in. (4.95-5.46 mm)
294 0.084-0.104 in. (2.14-2.64 mm) 0.087-0.110 in. (2.19-2.79 mm)
300 0.150-0.170 in. (3.81-4.31 mm) 0.205-0.241 in. (5.20-6.12 mm)
302 0.147-0.167 in. (3.73-4.23 mm) 0.212-0.244 in. (5.38-6.20 mm)
305 0.111-0.131 in. (2.82-3.32 mm) 0.135-0.159 in. (3.43-4.03 mm)
305, 343 (3) (1978) 0.073-0.093 in. (1.86-2.36 mm) 0.087-0.107 in. (2.21-2.71 mm)
335 0.160-0.180 in. (4.06-4.57 mm) 0.220-0.250 in. (5.59-6.35 mm)
337 0.157-0.177 in. (3.99-4.49 mm) 0.229-0.249 in. (5.81-6.32 mm)
338 0.111-0.131 in. (2.82-3.32 mm) 0.132-0.154 in. (3.35-3.89 mm)
340 (1970) 0.160-0.180 in. (4.06-4.57 mm) 0.198-0.228 in. (5.02-5.79 mm)
340 (1971) 0.160-0.180 in. (4.06-4.57 mm) 0.193-0.220 in. (4.90-5.59 mm)
343 (1972) 0.137-0.157 in. (3.48-3.98 mm) 0.159-0.179 in. (4.03-4.55 mm)
343 (1973) 0.111-0.131 in. (2.82-3.32 mm) 0.131-0.154 in. (3.33-3.91 mm)
343 0.111-0.131 in. (2.82-3.32 mm) 0.135-0.159 in. (3.43-4.03 mm)
345* 0.035-0.055 in. (0.90-1.40 mm) N/A
345 (1978)* 0.034-0.054 in. (0.87-1.37 mm) N/A
346 (1973)* 0.109-0.129 in. (2.77-3.28 mm) N/A
396 (1973)* 0.060-0.080 in. (1.52-2.03 mm) N/A
346, 396 (1974)* 0..071-0.091 in. (1.82-2.32 mm) N/A
354*, 454* 0.045-0.065 in. (1.14-1.64 mm) N/A
399, 440 (1970, 1971) 0.160-0.180 in. (4.06-4.57 mm) 0.148-0.171 in. (3.76-4.34 mm)
401, 434, 435 (1972) 0.137-0.157 in. (3.48-3.98 mm) 0.146-0.166 in. (3.71-4.22 mm)
401 0.111-0.131 in. (2.82-3.32 mm) 0.135-0.159 in. (3.43-4.03 mm)
434, 440 (4) 0.111-0.131 in. (2.82-3.32 mm) 0.118-0.144 in. (2.99-3.66 mm)
435 0.111-0.131 in. (2.82-3.32 mm) 0.119-0.141 in. (3.02-3.58 mm)
436* 0.071-0.091 in. (1.82-2.32 mm) N/A
440 (1975)* 0.071-0.091 in. (1.82-2.32 mm) 0.077-0.097 in. (1.96-2.46 mm)
440 (1987, 1979) 0.111-0.131 in. (2.82-3.32 mm) 0.120-0.140 in. (3.05-3.55 mm)
444 0.082-0.102 in. (2.10-2.60 mm) N/A
503 0.068-0.088 in. (1.82-2.32 mm) N/A

* Engines equipped with CDI
(1)  Use direct timing for engines with vertical spark plug holes; indirect timing for angled holes.
(2)  On 1972 models, indirect specification is the same as direct.
(3)  On 343 engines serial number 3,019,645 to 3,020,644 direct timing is 0.147-0.167 in. (3.73-4.23 mm).
(4)  Except 1975 440 with CDI.