Stalled on freeway after 25 mins of stop n go...overheated or carb issues?

[118811]

I was on the freeway today in stop n go traffic for about 25 mins...then I noticed my idle started increasing to about 1400, usually at about 1100.
Then bike started sputtering.
Got off to the side just before it died.

Waited 30 mins for Police assist to get bike to side street.

Bike started right up, and has been fine since.

Question....was this a "overheating" situation?
Is this typical of carbed M900's?

Thanks

[Howie]

Possible vapor lock, collapsing fuel line to the carb, fuel pump or vacuum fuel shut off failure due to heat. 

[118811]

Thanks Howie

Is that common for carbie bikes?

[Howie]

Over the internet I have no idea of how hot was hot.  The FI Monsters have a temperature gauge, yours doesn't.  If you weren't moving enough things can get real hot since you need airflow to cool things down.  At this point I would probably not worry much unless it happens again.

[motoxmann]

I've never had a stalling issue, but on hot days when sitting in stop and go traffic for long periods of time my carbed m750 does start idling really high, 1400-1500, then soon as I get moving and it cools back down again everything goes back to normal

[Timmy Tucker]

Mine does it all the time too. 15-20 mins in stop and go traffic and she'll start sputtering. Have to let her cool down for 30 mins or so before she'll run again.

[118811]

Well bike died again yesterday....it was moving and not in an "over heating" situation.

I hate intermittent issues.

I have noticed the last few months that my bike backfires occasionally on start up.  Then every now and then will  pop while running....

The PO and a mechanic, is thinking that it could be the ignition coils...?

Any thoughts....scared to take it out of the neighborhood now

[Howie]

Unlikely both coils are going at the same time.  The problem is more than likely everything will test good when the bike is running.  First check for spark, as it is quick and easy.  Carefully remove the spark plug wire, insert a thin screwdriver with a plastic handle or other suitable instrument into the wire cap, hold it about .030" from ground and crank. You should see a nice blue spark.  Now move on to fuel.  If the carb float bowl do not have enough fuel in them you have a fuel supply problem.  Carry a container and an 8mm. wrench with you.  On the right side the engine there two plastic lines.  If you follow them up you will see the float bowl drains.





Crack the lines open.  You should see a decent fuel coming out of the lines.  How much?  I don't know. 

Possible causes:
    Ducpainter's favorite part, the vacuum fuel shut off.  Replacing it with a manual petcock is a good idea.
    Fuel pump, they do get tired over time and the first symptoms are what you are experiencing.
    Weak (collapsing) hose from fuel pump to carb.
    Screen in fuel inlet to the carbs clogged (unlikely)
    Deteriorated vacuum line to fuel pump and/or fuel cut off.
    Fuel filter, if it older than one year or 6K miles, change it

[118811]

Howie,
Thanks for the ideas!!

I just rebuilt the fuel pump, and added a manual fuel shut off valve.  Fuel lines are all new within last year...I have had issues with my FCR's the past couple of years with dirt, debree clogging the floats.  Might be time to replace plug wires???
I think I will replace fuel filter too.

[ducpainter]

Howie,
Thanks for the ideas!!

I just rebuilt the fuel pump, and added a manual fuel shut off valve.  Fuel lines are all new within last year...I have had issues with my FCR's the past couple of years with dirt, debree clogging the floats.  Might be time to replace plug wires???
I think I will replace fuel filter too.

Did you use genuine Mikuni parts for the pump rebuild?

[118811]

Ducpainter.
yes, Mikuni rebuild kit 4 months ago

[118811]

S. T!!!
Stalled 3x in the last two days....traffic/accidents here in Honolulu

Towing to the Dealer Monday