1981 exciter 440 refuses to come back to life! - Snowmobile Forum: Your #1 Snowmobile Forum

JP250RV · 12-14-2012, 08:46 AM

HI i just joined this forum after reading through thousands of forum based search results over the years of fixing my many snowmobiles odd issues.

what i am dealing with now is my beloved 81 exciter 440. this sled was restored three years ago and was in tip top shape until i sunk with it in the middle of a blizzard by myself in the middle of my home lake, i nearly died in the accident, im an eagle scout and thats the only reason i was able to survive the ordeal. unfortunately the sled stayed at the bottom for about 3 months. after getting it back to land with the help of divers and the fire dpt i completely disassembled it and cleaned and oiled and rebuilt the whole thing again. when i fired it up it would run erratically like it had a rev limiter right when the clutch engaged. or it wouldnt run at all. i figured the stator was messed up mabe the cdi? so i purchased a stator, cdi, wiring, and coil from a guy in utah that had a crashed but running 81, got the parts and found that they were different from what i had. my cdi was a big aluminum box and the stator had two pulsor coils, long story short all i could figure out was that at some point my sled got a motor and components from a 79. so when i started it it would only run on the pto cly. figured out that the 79 flywheel has one set of grooves for the dual pulsar coils, so i got the flywheel from the same guy in utah. now when i started it yesterday it runs on the mag side cyl. ??? it has great spark on both plugs. which plugs should i be using. there br8es right now i read that some use br9ev and some use br9ev it ran great before with the 8s. also it use to have a retrofitted mikuni round slide, i got the original keihn carb and when it runs it has to be at full choke when you turn off the choke its like it runs out of gas and it will back fire pretty good before it dies, the fuel line is going to the black plastic inlet right at the bowl, and i noticed there is another inlet above that, what is that for? should it be blocked? thats al much info as ive got right now any help would be appreciated

JP250RV · 12-14-2012, 09:40 AM

I just went to napa this morning and got two br9es plugs, and just as i was about to start pulling it back apart to look for an issue i figured id try the plugs first. it started and ran on one cyl for a few seconds then it smoothed out and the second cyl lit up so i put it on the jack stand and gave it a blast of throttle and it was so nice to hear it scream like it never had been destroyed and rebuilt. what a relief, im assuming i had a dead plug before, i cant see just one heat range making that big of a differance. next question is what is that other inlet on the carb and should i pull a head off to get the timing perfect? i set the stator where there was marks from the washers its gotta be close. but is close close enough?

Yamaha440 · 12-14-2012, 11:30 AM

The stator changed from two pulsar coils to one in 1980. They are NOT interchangeable. This is what the supplemental service manual says. With all of the parts from a '79 on it, it will probably run correct now. Another change that could affect it is of the key switch in 1980 from a 3 position off on light to a 2 position off light. I don't know if it will cause repercussions with the '79 cdi, but they are listed as NOT interchangeable.

If you continue to use the '79 stator, you will have to pull both heads to time it, due to the 2 pulsar coils (one per cylinder). If you use an 1980 or later startor (cdi and flywheel required to be 1980 too) you only have to pull one head. Not timing it correctly could lead to it running rough, like the symptoms you described.

JP250RV · 12-14-2012, 12:35 PM

The stator that is installed is the single pulsar coil one. Im going to pull the mag side head and time it. I disconnected the killswitch for now. The key turns it on and off. Any ideas about the upper inlet on the carb?

Yamaha440 · 12-14-2012, 01:26 PM

Are you talking about the mikuni or the kehin? On the kehin, the upper inlet isn't supposed to have a line on it. It serves as a vent.

You may want to look into the fuel pump. Is the pulse line connected? How are the diaphragms?

JP250RV · 12-14-2012, 08:32 PM

Im talking about the keihn. That makes sence, i had a line on it today with a plug in it ill leave the line and remove the plug is it supose to connect to the airbox?

yamadad4 · 12-14-2012, 09:05 PM

your getting some top notch advice from yamaha440.

carb vent lines on that should be to free air, not to airbox. i have found that the amount of "dangle" is directly proportionate to running quality. in other words, dont drape a 6" tube off of that. just about enough to get you slighly past the bottom of the float bowl. makes for better bowl pressures.

JP250RV · 12-15-2012, 03:31 PM

Im very apprieciative for the info, i will put a line on it just like you said i think i remember an enticer i had having a vent tube like that, gotta time it though, should i loosen and slide rhe pulsar coul or loosen and clock the whole stator? Whats the approx adustment on the idle mix screw?

yamadad4 · 12-15-2012, 06:50 PM

couple of different ways to achieve proper timing. in my opinion, the best is using the dial indicator and comparing readings to the markings on the stator plate.

hopefully yamaha440 will chime back in and save me from digging out that crusty old book, wherever i put it.

in a nutshell, your going to roll the engine over to either bdc or tdc(bdc i think) on the mag cylinder, measure the distance and compare the timing marks on the mag flywheel and the case, or the stator plate and the case.

from there you can rotate either the plate and/or the pickup to be within certain given specs compared to piston location.

been awhile since i messed with one of those.

Yamaha440 · 12-16-2012, 06:08 PM

You will measure B.T.D.C. (before top dead center) 1.6 mm +- 0.1 mm (0.060 in +- 0.004 in). This can be done using the specific gauge, or by pulling the head, and using a depth micrometer.

Make sure that you have the stator roughly centered on the adjustments. Next, secure the fly wheel. loosen the pulsar coil(s). Next fix the mag cylinder at the timing spec B.T.D.C, and align the metal tab in the center of the pulsar coil with the hash mark on the flywheel. If it is aligned correctly, tighten the pulsar coil. If it doesn't quite line up, remove the flywheel, and adjust the stator in the direction it needs to go. Then start over.

Repeat the above steps if if you have two pulsar coils, only measuring the PTO side.

The timing mark is at the edge of the pulsar coil access hole.

yamadad4 · 12-16-2012, 06:33 PM

Quote:

Originally Posted by Yamaha440

You will measure B.T.D.C. (before top dead center) 1.6 mm +- 0.1 mm (0.060 in +- 0.004 in). This can be done using the specific gauge, or by pulling the head, and using a depth micrometer.

Make sure that you have the stator roughly centered on the adjustments. Next, secure the fly wheel. loosen the pulsar coil(s). Next fix the mag cylinder at the timing spec B.T.D.C, and align the metal tab in the center of the pulsar coil with the hash mark on the flywheel. If it is aligned correctly, tighten the pulsar coil. If it doesn't quite line up, remove the flywheel, and adjust the stator in the direction it needs to go. Then start over.

Repeat the above steps if if you have two pulsar coils, only measuring the PTO side.

The timing mark is at the edge of the pulsar coil access hole.

you are good! thanks. i will make note of this info for future reference. dont get much opportunity on the old iron.

whats your theory on head removal? better access or better measurement?

Yamaha440 · 12-16-2012, 07:10 PM

I use the head removal method out of improvisation. I don't have the gauge, and I haven't found a place to buy one. Personally, I feel that removing the head gives a better measurement, since you can double check your result with another caliper. Plus, if you've run it awhile, it's nice to decarbonize the heads as the manual says to do every season.

JP250RV · 12-20-2012, 08:34 AM

thank you very much for the info. as it is right now its got a wicked bog from idle to clutch engagement, after that its pretty good but i will confirm proper timing before i run it like i normally do.

Yamaha440 · 12-20-2012, 01:15 PM

If timing doesn't fix the issue, try cleaning your carb, focusing on the pilot jet. Then make sure the mixture screw is at 1 5/8 turns out from lightly seated.