When the engine just dies

[GypsyRR]

I was out riding for a couple of hours today, going about 75 mph on a country road and the engine just died. So while coasting, I looked all around the bike and nothing seems obviously wrong, so I pulled in the clutch lever and started it again on the first try and just kept on going. It didn't do it again the rest of the ride. I had just filled it up at Shell about 10 minutes prior.

So what's up with that? The gas?

[OU812]

Vapor lock. Or it did not like the Shell. I must say, that has never happened to me, without a reason found.

[toolinalong]

hmmm. extraterrestials. no doubt about it. they do that sometimes just to confuse us.

[MikeCam]

Can you recall if you had just hit/jumped/climbed/ridden over a road shock of any kind -- even a dip in the road at speed ?

Could be a temporary engagement of your side stand kill switch.

[awagnon]

Happened to me twice. Once while cruising along around 55 mph, just died. Started right up again, even before I coasted to a stop. The second time it happened on my street and I coasted into my driveway. I opened the tank to be sure there wasn't a vacuum from a clogged breather, but it was ok. Again, the bike started right up as if nothing happened. Have jiggled all the wires in the wiring harness for a broken wire from too tight zip ties. Jiggled the clutch, side stand, and main ignition switches and can't reproduce the problem. I mentioned it to two BMW mechanics and they had no idea. It leaves you wondering if the next time it just won't start again and you'll be out in the boonies somewhere.

[Spookymonster]

I get the same thing on occasion. Invariably, it seems to happen after topping off the gas. Vapor lock sounds the most likely. Any way to avoid this, or it just something we learn to live with?

[GypsyRR]

Can you recall if you had just hit/jumped/climbed/ridden over a road shock of any kind -- even a dip in the road at speed ?

No road shock (would have made a mental note of that, especially during yesterday's ride).

I mentioned it to two BMW mechanics and they had no idea. It leaves you wondering if the next time it just won't start again and you'll be out in the boonies somewhere.

Yep - that is my concern since I ride alone and frequent the "boonies" more than the populated areas.

[ProductUser]

With the engine running, turn the wheel to a full lock. Once at a full lock, jiggle some of the wire bundles in or around the bars and see if it dies.

Just a thought.

ProductUser

[acejones]

I doubt if its vapor lock. Not likely with fuel injection.

[CycleRob]

GypsyRR and others having this problem,

The next time this happens, look at the tach as the engine is spinning down in gear with it's life gone. If the tach goes to zero, you have an electrical problem. If it continues to read the RPM, it's a fuel problem. This test requires you have some road speed and the clutch is untouched, in gear, while you are coasting down with a dead engine. As soon as you get your answer from the tach, pull in the clutch and stop.

This type of problem can have many electrical fault type causes and finding it could frustrate even experienced mechanics. I agree on suspecting the wire harness that bends with the steering. It's the most likely cause and the easiest to diagnose. Bike idling on the centerstand, turn the steering right & left. Then message the dangling harness under the headlight. When the engine dies, you found it!! A tach going to zero in gear at road speed can also be caused by a broken harness wire there.

It can also be fuzzy/corroded fuelpump or Motronic relay contacts. Inside the sealed relay, so you can't check them easily. They're those small black rectangular cubes in two groups of two in the junction box. Swap one group of two with the other group of two relays - - - - they are all identical. When the problem later shows up in the horn or headlight, you found the villian. Of course, a flickering, dimming headlight at night can be an adventure, so be ready to use your nite vision.

[GypsyRR]

Thank you very much Rob. Fortunately, I read on this board about cutting cable ties which were too tight early in my ownership of my bike. I hope I did it soon enough before the ties were able to cause damage.

I'll run through those tests you suggested tomorrow and if nothing shows up, then I'll just have to wait and see what the tach says the next time it happens. Thanks also for explaining everything so simply that even I could understand!!

[CycleRob]

There is 1 other cause that happened to me years ago when my bike was new. Riding a narrow backroad uphill thru a rural small town when all of a sudden my engine SHUTS OFF like the key was turned off. I downshifted thru 4 gears with a dead, unresponsive motor until it stopped, which was very quick as the hill was steep. As soon as I stopped I hear loud talking, laughing and cheering like their team just scored a goal. I proceeded to check the fuses and just for kicks I remove and replace the Motronic fuse to reset it. Then I notice a huge 20 foot CB antenna, the kind that looks like a peace symbol, on the house where the ruckus was coming from. Seeing that, I remember my other bike, a 1990 Suzuki VX-800 that would sometimes run on 1 cylinder always in the same spot on my way home from work. That same spot also had a house with, you guessed it, a huge 20 foot CB antenna, the kind that looks like a peace symbol. It wasn't often but it was always in the exact same spot, like it was going on to the reserve fueltap setting. It did this with a full tank so after the 4th or 5th time I put 2 + 2 together and figured it out.

You electronics guys out there know just what happened. The close proximity to the high power transmission CB radio waves foul and distort the low voltage ignition trigger's pulsations so badly that the ignition computer reading them freaks out and does nothing !!!!

Back to my dead on the roadside R1150R, after checking the fuses and resetting the Motronic it started up and ran normally.
Right then and there I connected the loud cheers and talking to 3 or 4 guys watching certain vehicles flame out just when they key the mike and yell into it.

It's a good thing those power blasts did not cause any permanent damage to my bikes. The next time a flame-out happens to your bike, look for a huge CB antenna.

[toolinalong]

my supposition about extraterrestials needs to be extended to include terrestial aliens as well...ok.

[banjo]

I had a similar problem with my Red, 2004, non-ABS R1150RA. On my first trip out with it, I was heading north on the Eye 15 from San Diego, the first day out i was north of Salt Lake. Had stopped in Salt Lake for gas. My tank bag fit very snug over gas cap and seemed to seal the tank. Bike would die, and then start up before I coasted to a stop. I changed position of tank bag so as not to completly cover up gas cap, have not had same problem again.

Interesting about the CB signal, must have been running at least 500 watts to final of CB transmitter, very much a no no per FCC )