BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

Hi Guys, while riding home from work today, approaching a traffic light (decelerating) my bike backfired and stalled. After about 30 mins on the side of the road it started normally and I ride a few more miles before repeating this process 3 more times. The last two times I was maintaining speed, not decelerating. I'm assuming something electrical is failing at temperature, the questions is what?

Any help is appreciated!


Thanks.

Were you turning slightly?

If so its probably the dreaded ignition wiring failure at the headstock.

riceburner wrote:Were you turning slightly?

If so its probably the dreaded ignition wiring failure at the headstock.

Nope and I've gone through all the wiring on the front end of the bike when I re-wraped it due to the crumbling jackets.


Now that I've had a little time to dive in further, I've got spark.I can confirm that the side stand switch is good, the hall sensor is working (replaced a few years ago so wiring is in great shape).

Single spark, right?

I'm in the midst of replacing my ignition coil. Symptoms are not quite the same as yours though. I have rough idle and it seems to be missing at low RPM's. It did cut out on my this morning while I was coming up to a stop light. That was a first. Started back up. The new coil will be here next weekend hopefully. We'll see if it resolves my issue.

When my '02 R started having similar issues, it was suggested to replace the ignition leads bike was 7 years old at the time .
Replaced the leads and the stalling rough idle went away .
I found some deep chafe marks on the leads don't know if that was the issue or not, no more issues for the last 12 years .

by "leads", do you mean the spark plug wires from the coil to the plugs? Or, something else?

Yes, spark plug wires .

Alright, the bike now dies consistently within 2 miles of start-up. It will not start until its cooled down a bit. I've been able to do some troubleshooting during the time while it won't start.

Have a good battery.
Have spark.
Have fuel flow.
Side stand switch is good.



Any ideas?

Spark maybe showing when you check with your eye. It's different under compression. Sounds like no spark to me.

Coil is heating up and failing. Like swamper said you can have spark out of the cylinder but the coil won't provide enough voltage to jump the gap under compression.

Check ignition wire resistances.
Check ignition coil resistances.
Try opening the fuel-filler cap when it stalls and listen for sucking air. If it does, your vent hoses may be swapped.

Fuel tank venting problem?
Still have the charcoal vapor recovery canister?

sweatmark wrote:Fuel tank venting problem?
Still have the charcoal vapor recovery canister?

I've been thinking the same thing. Charcoal canister has been removed as a part of troubleshooting this. I haven't had a chance to go for a ride yet.

Thank you all!


Got it to die again today and worked quickly to find out that the Hall Sensor (TDC) is bad once warmed up. 180º sensor was fine. I was also able to replicate this failure with a heat gun.

This is a newer Bosch HES with only 8,000 miles on it. Guess I'm going to try the Enduralast brand and see how it does.