"Surging" problem page

Many BMW F650GS owners worldwide have in the past reported problems with poor running of the fuel-injected engine, either completely stalling on them while riding generally at lower revs or when changing down through the box, or more commonly surging of the engine, which varies from "breathlessness" at light throttle openings as if you are just about to run out of fuel and then the motor responding with a lurch as you twist on the throttle, or constant surging between 3,000 - 4,000rpm under light load.

GS models built before about March 2001 are most likely to suffer and in previous cases the problem was solved by a change to the injector used in the 1150cc BMW, but mainly the remapping of the electronics to v9.1. (v10.1 has now been released and according to the feedback it's curing the surging and stalling completely.) This latest fix, v10.1, does not require the original injector to be replaced, so if you still have the original injector don't bother to change it, especially if you're expected to pay for it. The v10.1 update was developed to be compatible with either injector, (at least for the UK).

The injector and software upgrades are not automatically covered by BMW warranty and some dealers may charge for the modification, so your dealer will need to get 'Head Office' approval if you require the upgrade for free.

This paragraph added as a result of an email to me from BMW (UK) technical dept.
It is worth noting that the starting procedure for the F650GS is very important. It is as follows. Turn on the ignition, wait for heater light to go out and press the start button until the engine fires. DO NOT open the throttle in this process as the throttle position sensor signal is not permanently remembered by the control unit, (as with other systems). The control unit takes a reading during the first few crankshaft revolutions. If the throttle is opened, then the base throttle setting will be incorrect for the duration of the engine running.

The older injector that was suspected of causing a surging problem is numbered BMW 1354 7652159 or Bosch 0280 156026. NOTE - these do not need to be changed with v10.1 software update.

The new replacement injector which was expected to resolve the problem is numbered BMW 1371 1342366 or Bosch 0280 155788, but they didn't always solve the problem completely with the v9.1 update, as I and a number of others have found.

The BMW part number for the new injector is 13 71 1 342 366 and currently costs £50.01. If the software update v10.1 works as promised then it is not necessary to change injectors, because the v10.1 has been developed to work with both the *old* and *new* injectors. Note if a new injector is fitted the BMS unit must be reprogrammed with the latest software, as it will not work correctly with the original software.

The injector can be viewed by lifting the seat and looking forward beneath the dummy tank, (which doesn't need to be removed). It is generally a greyish colour about the size of your little finger, with wires coming from it. The numbers are quite small so you might need a magnifying glass to identify them.

In my case the new injector and the v9.1 software upgrade improved the usability and tractability of the engine immensely, but it's still wasn't perfect.

I had the v10.1 upgrade done on my F650-GS on 30 Sept 01 and I first noticed that there's less engine braking and the revs do not drop back to tick-over as quickly as before. I presume that's because a 'small' amount of fuel is still being injected into the cylinder on the overrun, to combat the 'Stalling' problem, whereas previously I understood that the fuel supply was completely shut off on the overrun until 1,800rpm was reached.

I never had a serious 3,000-4,000rpm surge so can't comment on that. The hesitation when going from off-throttle to on-throttle at around 2,000 - 2,300rpm has now gone, so trickling along in rush-hour traffic has much improved. I did find previously that different brands of petrol and weather conditions seemed to affect how problematic it was. I've put on 2,000 miles since the update I can now say that I'm very happy with the way the GS runs with the v10.1 software.

Sometimes the problem can be traced to the fuel pressure regulator/modulator which if not capable of maintaining the correct pressure can cause either stalling or surging, so if latest updates do still not resolve your problem then you need to get your Dealer to do further investigate work.

From the USA there is non-BMW electrical "black box" accessory referred to as the Techlusion "Fuel Nanny" or "Powebox" which is produced by a private company which many USA riders on the "Chain Gang" list have claimed has completely resolved their stalling and surging problems, and giving even better miles-per-gallon to boot! The website of the product is http://www.techlusion.com/Intro.htm and the claims made so far seem to be effective. Every day on the 'Chain Gang' message-board I read of more and more GS owners singing the praises of the 'Fuel Nanny'. 

Having not tried it myself I can't say if it works or not, but I understand that Techlusion are considering offering it to BMW as a device to cure the "S & S" problem.

I have recently received an email from BMW HQ (UK) requesting that owners with problems please use their local BMW dealer to resolve the "Surging & Stalling" problems, as all dealers are now aware of the problem and the v10.1 "fix".  As a last resort you can email me trevorgeorge@blueyonder.co.uk and I will give you further information for contacts at BMW (UK) if your dealer cannot or will not fix it.

My contacts at BMW (UK) and my local BMW dealer, Bath Road Motorcycles, have helped me so far in improving my GS.  It now seem to be running perfectly - as a BMW should!