Engine stall at stops, "jerky" when letting off throttle at speed

[bobfately]

I now have 37K miles on my 2014 C650GT, and for the past few months (3-4K miles or so) my bike has been having this occasional issue of stalling out at a stop or not slowing down smoothly when I let off the throttle (whether at 30MPH or 90MPH - speed doesn't seem to matter).

I have had all services done by the dealer, and it was a couple of months after the 30K service that it started to happen. It first appeared one evening when I returned home at LAX on a somewhat dank evening - the bike stalled 6+ times just getting out of the parking lot. It got to the point where I had to hold the throttle to a mild rev while simultaneously applying the rear brake, just to prevent the constant stalls. Since then, however, it has not happened nearly as badly or often - I've taken it to the dealer a couple of times (and reported it at the 36K service as well) but they can't replicate the problem.

Mind you - this stalling out only happens when I'm at a complete stop - but generally, if at all, after I've ridden the bike at least a few dozen miles (highway or street).

I had always used Shell gas - the dealer said keep away from Shell, Chevron is much better - so I've been using that for the past couple of months to no effect.

My question is - has anyone else got this kind of miles on their bike - could it have to do just with that? Seems ridiculous to me that the scooter would start to have issues at only 33K miles, but has anyone gone through this at all?

TIA

Bob

 

[t6pilot]

My buddy had a similar issue with his RT, while we were on a long ride. My theory on the cause was the 10% stuff mixed with our gas (think corn)
We stopped at a NAPA auto parts store and bought a couple cans of SEAFOAM INJECTOR CLEANER
First time adding doubled the dose, then for the next couple of fuel stops added the desired amount
After the first stop problem went away, recommend regular use of SEAFOAM or TECHRON as our gas can clog injectors and interrupt spray pattern causing your problems

 

[bobfately]

My buddy had a similar issue with his RT, while we were on a long ride. My theory on the cause was the 10% stuff mixed with our gas (think corn)
We stopped at a NAPA auto parts store and bought a couple cans of SEAFOAM INJECTOR CLEANER
First time adding doubled the dose, then for the next couple of fuel stops added the desired amount
After the first stop problem went away, recommend regular use of SEAFOAM or TECHRON as our gas can clog injectors and interrupt spray pattern causing your problems

Thank you for this, t6 - another friend of mine also recommended Sea Foam this past weekend.

 

[t6pilot]

Bob
Keep us posted, curious as to the fix

Jim

 

[rangerreece]

This worked for my F650GS

http://youtu.be/uvkKpMTRI3Y

 

[bobfately]

It got better, then it's back

http://youtu.be/uvkKpMTRI3Y

First of all, thanks for that link, @rangerreece - quite interesting. Of course, there seems to be no availability of manuals or instructions as to how to get to, much less, replace the spark plug in the scooter.

Just as follow-up, I did use SeaFoam and after a few tanks-full worth of application it did improve. Brought it to a different (and more local) dealer in the San Fernando Valley (West Valley Cycle Sales) for the 42K check and was told the computer readout has to do with RF interference. Mind you, I did not mount a ham radio on the handlebars or anything... just had the same Garmin GPS mount on a RAM Mount on the left handlebar (often without the GPS unit mounted) that's been there since I got the bike, so it doesn't make logical sense to me that RF suddenly jumped out of that after 18 months of use.

Anyway, things settled down after the SeaFoam for a while but in the pst week or so the stall-at-idle and jerky-slowdown from speed issues have been recurring.

I might just bring it in again, this time citing the spark plug and computer reset ideas. Or maybe just will disconnect the battery for a couple of hours,then start the bike and leaving it at idle until the fan kicks in to see if that resets things properly.

Again, just wanted to thank you guys and let you know I will keep you apprised. I don't know if I'll be the first person to hit the 48K service mark on a C650GT, but that ought to happen around June at the rate I'm going.

 

[rangerreece]

I just rest my recently. Dropped a battery lead bolt in the guts of the 650. Had to Depannel until I found it. 15 minute project turned 2 hours. Anyways, when I reset the motronix I touch the leads together to dispate the charge. Cleared it up again. 650's are fickle creatures.