skier
05-04-2010, 08:32 AM
I've been having a progressively worse problem with my '91 250x that seems to be spark related, but I've yet figure out what's wrong...
Here's what it used to do when the problem first started:
It would start just fine when it was cold. It would run fine both cool and hot, and I could ride it for hours, as long as it stayed hot, but if I stopped it for more than a minute or two and let it cool a little, then I'd have a hard time starting it, eventually wearing myself out trying to start it, so then I'd hook up a tow strap to tow start it, and after pulling in (usually) 3rd gear, and playing with the throttle a little, it would fire up and as long as I kept it running for a minute or so by keeping the engine revs from getting too low, then it would [seemingly] heat back up and keep running/idling just fine again. Likewise, if it died and started it again quickly it would start again, but not if I let it sit too long.
Here's what it does now...
It has progressively gotten worse, so where it wants to die more often when the engine revs are lower; like I might just be sitting there idling and it will die and not want to start again. If I pull the plug and check the spark, I don't get spark...
The most irritating thing is that it's an intermittent problem, so hard to troubleshoot. I've checked/changed the plug, check all the resistance checks I can find in the book (e.g. primary and main ignition coils, exciter coil, etc), and checked the AC voltage output, etc and everything seems to be pretty much in spec. When I tried to repeat the problem at home (instead of say Sand Lake) I let it idle and it die fine for a long time, never died, turned it off for a few minutes, started up, ran it more, turned it off longer, still started fine. Rode it up and down some big hills in my neighbor hood to put a load on it (in case it mattered, since it was only like 40F outside), then let it idle again until the head was up to about 400F (measured by an IR multimeter that also measures temp) and the gas in the tank was actually boiling, but it just kept running and starting fine. It also had no issues when took it back to central Oregon back in Feb, but it was only 20-38F outside when we were riding, so maybe temp has something to do with it. Went to Sandlake a month or so ago (~50F) and I had problems all day, having to be pull started each time, but the running fine for a while after each pull start and turning my idle up fairly high.
This seems to be a pretty bizarre problem that I just can't seem to figure out. Things seem in spec, but intermittent. I also disconnected and reconnected pretty much every electrical connector I could find on the outside of the bike.
Anyone have any idea on things I might do to troubleshoot this further? Thanks.
-Mike
Here's what it used to do when the problem first started:
It would start just fine when it was cold. It would run fine both cool and hot, and I could ride it for hours, as long as it stayed hot, but if I stopped it for more than a minute or two and let it cool a little, then I'd have a hard time starting it, eventually wearing myself out trying to start it, so then I'd hook up a tow strap to tow start it, and after pulling in (usually) 3rd gear, and playing with the throttle a little, it would fire up and as long as I kept it running for a minute or so by keeping the engine revs from getting too low, then it would [seemingly] heat back up and keep running/idling just fine again. Likewise, if it died and started it again quickly it would start again, but not if I let it sit too long.
Here's what it does now...
It has progressively gotten worse, so where it wants to die more often when the engine revs are lower; like I might just be sitting there idling and it will die and not want to start again. If I pull the plug and check the spark, I don't get spark...
The most irritating thing is that it's an intermittent problem, so hard to troubleshoot. I've checked/changed the plug, check all the resistance checks I can find in the book (e.g. primary and main ignition coils, exciter coil, etc), and checked the AC voltage output, etc and everything seems to be pretty much in spec. When I tried to repeat the problem at home (instead of say Sand Lake) I let it idle and it die fine for a long time, never died, turned it off for a few minutes, started up, ran it more, turned it off longer, still started fine. Rode it up and down some big hills in my neighbor hood to put a load on it (in case it mattered, since it was only like 40F outside), then let it idle again until the head was up to about 400F (measured by an IR multimeter that also measures temp) and the gas in the tank was actually boiling, but it just kept running and starting fine. It also had no issues when took it back to central Oregon back in Feb, but it was only 20-38F outside when we were riding, so maybe temp has something to do with it. Went to Sandlake a month or so ago (~50F) and I had problems all day, having to be pull started each time, but the running fine for a while after each pull start and turning my idle up fairly high.
This seems to be a pretty bizarre problem that I just can't seem to figure out. Things seem in spec, but intermittent. I also disconnected and reconnected pretty much every electrical connector I could find on the outside of the bike.
Anyone have any idea on things I might do to troubleshoot this further? Thanks.
-Mike