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.

 

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 😉

 

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.

 

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.

 

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.

 

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!

 

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.

 

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.

 

mine is a 2014 GT-----I always noted that smoothness was not its forte----but whilst giving it a winter start-up I tried holding steady revs at both 2000 and 3000 ----it just doesn't want to know! with the throttle 'locked' it will vary 100 rpm above and below the target revs. Not sure if this is typical of the genre ---or if there is something wrong, any input would be appreciated.