Low speed surging - BMW F800 Riders Forum & Registry



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  1. #1
    Right Hand Drive's Avatar
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    Two days ago I popped the bike in dynamic mode and noticed it surging when trying to hold a steady 30 mph through town. Changed it back to road mode and the surging, while still there was considerably reduced. Anyone notice surging on the fly by wire GT at low speeds? The bike was recently serviced (basically oil and filter change), had a fresh tank of gas and outside air temp was about 11 degrees. I was riding at around 200 ft above sea level. Bike is a 2018 GT with 2000 miles on the clock.
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  3. #2
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    Is this the year/update when the GT got a ride by wire throttle? I don't know if the TPS reset still works on the GT/this set up but probably worth a try to see if it cures the issue.
    BMW F800ST, 2010, Black, Fuzeblock, Sat Nav, BMW Tank Bag, Givi Touring Screen, Denali Spotlights, Denali CANSmart, Wunderlich Crash Bars, 55K Miles & counting 

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    Shouldn’t happen. Maybe change to Road, give it an Italian tune up. Change back to Dynamic, give it another Italian tune up and see if the problem is still there.

    I use Dynamic all the time, even when it rains. Those few days when it was snowing, I switched to Road 😉

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  6. #4
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    Quote Originally Posted by Right Hand Drive View Post
    Two days ago I popped the bike in dynamic mode and noticed it surging when trying to hold a steady 30 mph through town. Changed it back to road mode and the surging, while still there was considerably reduced. Anyone notice surging on the fly by wire GT at low speeds? The bike was recently serviced (basically oil and filter change), had a fresh tank of gas and outside air temp was about 11 degrees. I was riding at around 200 ft above sea level. Bike is a 2018 GT with 2000 miles on the clock.
    Rich,
    In Oct'19 I traded my 2013 for a new GT [one of the last].
    Thanks to a foot problem followed by Covid lockdowns, I have only ridden new bike 3,700 miles but enough to rate the throttle control far better than 2013 GT and a previous 2007 ST. I have not experienced the surging you report. As a 2018 bike it may still be within BMW UK 3 year warranty ---- if so, don't waste any time, take it to a dealer for check out.
    Please let us know how it is resolved.
    Last edited by chris f; 03-24-21 at 04:12 AM.

  7. #5
    Dalesman's Avatar
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    Could it not just be the increased sensitivity to the slightest movement of the throttle in D mode?
    I find fuelling at slow speeds to be a bit lumpy in road mode even with fly-by-wire. I also find 30 mph to be a speed at which 1st feels a tad too low a gear and 2nd feels a little too high. I have no experience of previous versions of GT/ST.
    I'll have a go in Dynamic mode at 30 next time I'm out and see what it does.

  8. #6
    Right Hand Drive's Avatar
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    Thanks for all the replies. I agree with Chris that the throttle response on my 2018 (fly by wire) seems generally much better than it was on my previous GT and ST (both with cable throttles), apart from this surging which only appeared recently. I had thought about the TPS reset procedure which I'll try, though no idea if it will work on the fly by wire. I also wondered about the sensitivity of the throttle in D mode as suggested by Phil. It is quite pronounced in D mode. Much less surging in Road mode but still noticeable. The bike has hardly done any miles over the winter so an Italian tune up might wake it up. Think I'll try that as well. It did have its service at a dealer back in December, so I imagine any problems would have been detected. However, as a last resort I may take it back to them since the warranty is still active. Over the winter I kept a full tank of gas and added some fuel preserver to stop the system gumming up, but I recently ran the tank down to empty and then refilled with fresh fuel so I doubt the fuel is an issue. Be interesting to see how you find yours in Dynamic mode at a constant 30 mph Phil.
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  9. #7
    Dalesman's Avatar
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    Had a go today. 2019 GT. Constant 30 mph in 1st gear @ 4.5K revs and constant 30 mph in second gear at 3K revs. There was no noticeable surging in either Dynamic or Road modes. It felt just as smooth as it does maintaining constant speeds at higher speed in higher gears. 'Smooth' of course is relative - this is a twin cylinder motor and maintaining a perfectly constant speed on anything but perfectly smooth surfaces (hard to come by in the UK) is not especially easy. But no discernible surging.

  10. #8
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    Quote Originally Posted by Dalesman View Post
    Had a go today. 2019 GT. Constant 30 mph in 1st gear @ 4.5K revs and constant 30 mph in second gear at 3K revs. There was no noticeable surging in either Dynamic or Road modes. It felt just as smooth as it does maintaining constant speeds at higher speed in higher gears. 'Smooth' of course is relative - this is a twin cylinder motor and maintaining a perfectly constant speed on anything but perfectly smooth surfaces (hard to come by in the UK) is not especially easy. But no discernible surging.
    I think the good clean northern air helps!

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  12. #9
    Dalesman's Avatar
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    Quote Originally Posted by chris f View Post
    I think the good clean northern air helps!
    Well. Good clean Yorkshire air anyway. Not so sure about the stuff on the other side of them hills.

  13. #10
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    Rich. This may sound a little odd but an over tight drive belt will make the throttle very sensitive. You mentioned that you've recently had it serviced by a dealer, did they re-tension the belt (without telling you)? Might be worth a check.

  14. #11
    Right Hand Drive's Avatar
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    Dave. That's an interesting thought. Yes, on the face of it seems a little odd but thinking about it some more, it makes a lot of sense. I'll check it out. The surge has only started recently, so it could be something to do with the service.
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  15. #12
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    Quote Originally Posted by Right Hand Drive View Post
    Dave. That's an interesting thought. Yes, on the face of it seems a little odd but thinking about it some more, it makes a lot of sense. I'll check it out. The surge has only started recently, so it could be something to do with the service.
    Perhaps the dealer updated your bike's firmware with the latest new and improved BMW lean-burn EU emissions and environment-friendly FI programming.
    Richard - Current bikes: 2016 BMW R1200RS, 2018 16.6 kWh Zero S, 2011 Royal Enfield Bullet 500 Classic, 2009 BMW F650GS, 2020 KTM 390 Duke, 2002 Yamaha FZ1 (FZS1000N) and a 1978 Honda Kick 'N Go Senior. 

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