So i've been trying to troubleshoot a pesky 2007 M8 since Saturday afternoon. short version of symptoms: it will stall out and refuse to restart. Troubleshooting on Saturday confirmed that it has at least some spark, fuel at the rail is under pressure, and it definitely has compression. Since then, it's generally been happy to start in my garage but not in the field, and when it does die in the garage, it will idle up to about 3300k, stay there briefly, and then drop steadily to about 1200 when it dies. Unplugging the handlebar or hood harnesses don't seem to affect much. Unplugging the temp sensor let it start up when it wasn't wanting to but then resulted in a highly variable idle and the sled dieing.
Long version below:
I bought this and an 08 M8 on friday, rode from the Pilot lot into Cooke City Friday night, and used them for sled skiing Saturday morning. Around 12:30 - 1:00, snow was starting to get a bit sketchy on anything steep enough to ski, so we decided to ride around and explore a little; I got a little over-excited, hit a tree with the '08, toasted the left-side a-arms, and buried it pretty well by the time we got it disentangled from the tree. By the time we had it dug out, the '07 (which until this point had been happy) had probably been sitting about 45 minutes to an hour. My friend went to pull the '07 around with the idea of helping pull the '08 out of its hole, and it stalled out and died.
At that point, I pulled two of the more-accessible plugs, which were wet but otherwise looked good. In case of any sort of flooding or vapor lock, we pulled it over with the plugs out, confirmed it had spark, and put them back in..at which point the next pull fired it up. A couple other guys stopped by and helped pull the '08 out by hand.
My friend rode the '07 back to town, while I skied back, meeting her when things got flat and getting towed back in. It ran fine until I hopped on it at the paved end of Main st., at which point it stalled outside of Bearclaw Bob's. Got it going again a little later, made it almost to the Exxon; and then the last time was about ten feet or so. We let it sit overnight, no joy in the morning; it seemed to have at least weak spark, definitely had fuel pressure at the rail, and had compression. I pulled the belt and we towed it back to Pilot.
Sunday night in my garage, my roommate noticed the ignition trim ring was loose; we thought perhaps the key hadn't been clicking all the way to on, as the sled ran fine in the garage after tightening that. Monday night, I tried to take it out locally, and it ran on the trailer almost long enough for me to get my helmet, goggles, glove and pack on (probably 2-3 minutes) before stalling out and dieing.
With no changes since then (it had been sitting, covered, on my trailer), it didn't want to start. I unplugged the (unused) accessory wire sensor near the ignition, it started, revved high (around 2500 RPM), drops below 1800 and dies after about 45-60 seconds.
Plugged the plug on the accessory wire back in, fired it up, let it idle for two minutes during which it stayed at 1700-1800 for 2+ minutes.
Tried wiggling handlebar, no effect.
Tried hitting warmer controls, revved up near 3300, dropped low (1200ish) and died.
Pulled it over, it fired up, revved up near 3300, dropped low, and died.
Thinking something on the bars was responsible, I unplugged the handlebar harness, restarted, and let it idle for about three minutes (around 1700-1800 RPM the whole time).
I reinstalled the bar plug, pulled it over, and it idled fine for over a minute and a half.
I tried changing the heater switches, first one than the other, with no changes.
I tried turning the bars to the left and it repeated the high-idle, drop low, die routine.
I turned off the heaters again, revved high and died.
Then I unplugged the handlebar harness...and again, it started up, revved to around 3k, dropped below idle and died.
Any thoughts? I'm planning to start checking resistance on coils and the like, but this seems a lot more wonky and intermittent than a simple ignition fault.
Long version below:
I bought this and an 08 M8 on friday, rode from the Pilot lot into Cooke City Friday night, and used them for sled skiing Saturday morning. Around 12:30 - 1:00, snow was starting to get a bit sketchy on anything steep enough to ski, so we decided to ride around and explore a little; I got a little over-excited, hit a tree with the '08, toasted the left-side a-arms, and buried it pretty well by the time we got it disentangled from the tree. By the time we had it dug out, the '07 (which until this point had been happy) had probably been sitting about 45 minutes to an hour. My friend went to pull the '07 around with the idea of helping pull the '08 out of its hole, and it stalled out and died.
At that point, I pulled two of the more-accessible plugs, which were wet but otherwise looked good. In case of any sort of flooding or vapor lock, we pulled it over with the plugs out, confirmed it had spark, and put them back in..at which point the next pull fired it up. A couple other guys stopped by and helped pull the '08 out by hand.
My friend rode the '07 back to town, while I skied back, meeting her when things got flat and getting towed back in. It ran fine until I hopped on it at the paved end of Main st., at which point it stalled outside of Bearclaw Bob's. Got it going again a little later, made it almost to the Exxon; and then the last time was about ten feet or so. We let it sit overnight, no joy in the morning; it seemed to have at least weak spark, definitely had fuel pressure at the rail, and had compression. I pulled the belt and we towed it back to Pilot.
Sunday night in my garage, my roommate noticed the ignition trim ring was loose; we thought perhaps the key hadn't been clicking all the way to on, as the sled ran fine in the garage after tightening that. Monday night, I tried to take it out locally, and it ran on the trailer almost long enough for me to get my helmet, goggles, glove and pack on (probably 2-3 minutes) before stalling out and dieing.
With no changes since then (it had been sitting, covered, on my trailer), it didn't want to start. I unplugged the (unused) accessory wire sensor near the ignition, it started, revved high (around 2500 RPM), drops below 1800 and dies after about 45-60 seconds.
Plugged the plug on the accessory wire back in, fired it up, let it idle for two minutes during which it stayed at 1700-1800 for 2+ minutes.
Tried wiggling handlebar, no effect.
Tried hitting warmer controls, revved up near 3300, dropped low (1200ish) and died.
Pulled it over, it fired up, revved up near 3300, dropped low, and died.
Thinking something on the bars was responsible, I unplugged the handlebar harness, restarted, and let it idle for about three minutes (around 1700-1800 RPM the whole time).
I reinstalled the bar plug, pulled it over, and it idled fine for over a minute and a half.
I tried changing the heater switches, first one than the other, with no changes.
I tried turning the bars to the left and it repeated the high-idle, drop low, die routine.
I turned off the heaters again, revved high and died.
Then I unplugged the handlebar harness...and again, it started up, revved to around 3k, dropped below idle and died.
Any thoughts? I'm planning to start checking resistance on coils and the like, but this seems a lot more wonky and intermittent than a simple ignition fault.
Last edited: