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New Owner, surging erratic idle issue

jasper650

New member
Hi all,

Just recently bought a 2014 g650gs Sertao w/4400 miles on it from a private seller. Ran great when I checked it out. Ran great for about 100 miles, then I noticed it surging a bit and idling erratically--varies between about 1,000 and 2,200 rpm when sitting at a stop. A few times I've downshifted and gone into corners in 3rd or 4th and it just loses all power, then takes off. I've done quite a bit of online reading and researching over the past few weeks and I'm seeing others with these single cylinder bikes having similar issues, with all sorts of recommendations on fixes. Everything from starting procedure (no throttle, wait for all lights to go out, hold button in for three seconds -- I've been doing this), turning on key, not starting, open throttle up and close twice, disconnecting battery for awhile to reset the ecu (did this, left it unhooked for about an hour), changing to extended tips iridium plugs (I've worked on older 80's Japanese bikes, this is my first "new" bike and this process seems kind of complex and made moreso by the lack of repair manuals for this bike. I also have stumbled across info about a recall on these bikes for stalling issues--the fix is a software update, but I've read a number of folks who've said this didn't solve their issue. Anyway, I wound up taking to my BMW dealer, fifty miles away, for a state inspection and check over. The software now at the current version, and they thought that wire routing for some aftermarket Denali driving lights was interfering with the throttle rotor. Picked the bike up, rode it about a hundred miles without issue, the next day went for a ride and it started doing the same thing again.

Is this just a quirk of these bikes that I have to live with or does anyone have any thoughts on what else might be going on here? Very frustrating to buy my first modern bike and be dealing with issues right out of the gate on a bike with such low mileage. Thanks in advance for any thoughts/advice.
 
I had issues with my 2013 650 GS that may or may not be similar to yours.

My bike would not surge at idle as you discussed but it would cut out while riding. The tach would indicate a rise in RPM to red line - even though the RPMs were not actually rising. At the indicated red line the engine would drop all power.

The dealership changed out the fuel pump which is pretty expensive because the OEM pump comes with the pump carrier. Solved the problem for a while then the problem started again. Service department did not have an answer and BMW NA did not help.

I bought a used ECU, used fuel filter and pressure regulator, used stick coils and a cheap E-bay fuel pump (something like $20.00 - without the carrier). I started switching parts to see if I could eliminate the issue. When I got to the fuel pump the problem went away. The fuel pump can be swapped out in the OEM carrier. BMW makes a special wrench to remove the collar from the tank. I have one and bought another spare e-bay pump but have not had the problem again. You do not necessarily need the special tool but it makes it easier than trying to unscrew the collar otherwise.

Another possible issue could be that the tank was overfilled and the charcoal filter to capture fumes is saturated and the venting of the fuel tank is not working. It seems like there is a separate vent. If it is surging at idle, open up the gas cap and see if it stops surging.

Love to hear what you find out on this.

Maybe you could tell us where you are in your profile so if someone close to you wants to help they can.

Its a great bike.

Welcome to the forum.

Wayne Koppa
Grayling, MI
#71,449
 
Thanks, Wayne. I’m up in Vermont and will update my profile shortly!

As for the bike, I took it up to the dealer last night and while it wasn’t doing it’s idling problem when I dropped it off, the guy did say that having sold lots of these bikes he could tell that something just wasn’t right with it. He also said it might be a headache to try and find the culprit, so fingers crossed. Thanks for the info on all that you did, that could be helpful if I wind up having to dig into on my own instead of letting the shop try and find it—that’ll get pricey pretty quick I think.

Can you recommend a manual for these bikes? I’ve seen a few folks saying the Haynes manual for the F series are similar enough, but I’m not familiar enough with BMW’s in general to feel confident in that.

Thanks again,
Josh
 
Thanks all. Update on this. Bike spent two full weeks at the dealer. They found no smoking gun, but, they went through and tested all sensors, checked the charcoal canister and all vacuum hoses, new air filter, new spark plugs, and just gave it a full going through. I've since put on about 400 miles, a mix of short to the store and back runs and a couple 100+ mile rides and it's running perfectly. Posting this in case anyone else has similar issues, though again, there was nothing conclusive found. Thanks again for the thoughts.
 
Hi all, I was having the same problem this week with the 2015 g650gs I bought recently. Every time I pulled in the clutch, the bike was stalling. The technique mentioned in this thread worked perfectly:

1. Turn off bike if running
2. Turn key to on position but do not start
3. Twist throttle three times
4. Press start button without touching throttle

Worked for me. Idle reset to normal, and no stalls at stop lights.
 
Update on this

Just posting this as an update in case someone else has this issue or similar. After the mechanics went through the whole bike and checked everything it ran fine for the rest of last season. This year it ran fine for the first 1,000 miles, then started to do the same thing. Given the price tag to have it fixed and the fact that they never found anything, I didn't want to go that route. After lots and lots of research I found some info through this site: https://www.f650gs.crossroadz.com.au that led me to a piece of info about a faulty BMS/ECU on some of these bikes. However, the "fix" here is simply unplugging the computer itself, letting it sit for a few minutes, then plugging back in. This past season I had to do this twice, once in the garage after the bike started acting up, and once on the side of the road miles from home. Both times this has immediately solved the problem and it ran fine for 1,000 or so miles. So, that's my fix. Quirky little bike, but I love it!
 
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