Electrical Gremlin?

[Boxer Briefs]

The Scene- A hot (107F) day in north central Montana. A rest stop is made for hydration and shade, although the lovely '03 R1150R is left in the sun on tarmac . This is the 13th riding day (ah, lucky 13!) of a Seattle to NYC round trip with essentially flawless performance by the Roadster. After about a 20 minute break it's time to continue on- bike in neutral, sidestand up, press starter button and she turns over but won't start. Again, same thing. Third try, she starts. Clutch in, first gear and she dies as I begin to let out the clutch. Clutch in, starter button- won't start. Neutral, starter button- won't start. The bike is now placed in the shade and trouble shooting begins, well, after a couple more foolish pushes on the starter button of course.

During the course of troubleshooting, the bike did actually start a couple of times, would idle briefly... and then die. An apparently intermittent electrical gremlin, we eventually determined that there was no spark. I was reluctant to get back on the highway and have it fail, but I had a suspicion that something was overheating and that if she started again and we got rolling, the cooling air would "fix" it and all would be well.

Sure enough, after waiting a spell, she fired up and away we went, off into the sunset, complete with a lovely thunderstorm.



Three days and approximately 1,500 miles later I was back home without a recurrence of the problem. Now it's seven months and 4000 miles later and all has been well, but I know it's not truly fixed. Does anyone here have any ideas about what may have caused this? Your insight would be greatly appreciated.

Thanks,

Grant

[Airman]

Grant,

My first thought was the sidestand switch. No ratiional reason of course, but you didn't have ignition and that's one of the things that would let you crank without fire. If it were really heat related it surely would have occurred again during that run. After much abuse, my sidestand has gotten sticky and no longer will retract on spring pressure alone. I have to bang it up with my foot to get ignition.

[MikeCam]

Vapor lock still happens.

[bmwr1150rbmw]

Hey Grant, Glad you were able to continue. Question: Did you ride roundtrip from NYC to Seattle in sixteen days? What was the daily average? Was your trip comprised of the northern route to and fro. I'm planning the same trip for this summer. Thanks, Patrick

[Beemeridian]

11

[Sunbeemer]

Since you determined there was no spark, I'd say vapor lock was not the issue, but it was my first thought too.
Did you happen to notice once you got it running if the tach was erratic? That would indicate Hall sensor wiring failure, but the bike probably wouldn't be running again if so. An overheated ignition coil perhaps -- once running again, did it miss at high rpm's?

Still sounds more like a fuel issue to me though, as others have suggested.

[MikeCam]

My guess is the numerous starter attempts drained the battery. So the spark test was invalid at that point. Still reads as classic vapor lock. Could also be heat induced coil failure - intermittent and self-correcting.

[Boxer Briefs]

Thanks for your help folks. Vapor lock was mentioned by my riding partner that day but we dropped that line of thinking following the spark test. After reviewing the comments here, I'm inclined to believe that vapor lock was indeed the culprit, although there is the tiniest bit of doubt. Either I botched the spark test or MikeCam is right re: the battery being too drained for a reliable test. And once we were up and running again, no issues with the tach and smooth sailing. Thanks again!

And Patrick, I'll reply to you soon.

Grant

[tkm]

Based on my own experience with something very similar I would say the primary coils are the culprit. Mine kept working some 4000 miles after the incident albeit with a high speed miss before giving out completely . Good luck.................tkm