Interrupted engine breaking

[GSgirl]

After the 6K service my 12GS (2012) has started to ‘burp’ when engine braking on longish descends. Along with that comes a ‘fart’ which is normal for this bike, but the burp causes an acceleration because while burping the engine braking stops. Thus making for a shove forward which is unexpected and not pleasant. It’s as if I’ve quickly engaged and released the clutch, which I haven’t.

With such a new bike and because it suddenly started after the 6K service I doubt it could be a slipping clutch. I worry this is motor management (ghost in the machine). Could it be the throttle sensor or the throttle motor valve? (Not sure about these technical names in English..) So far dealer has reset the valve inside the exhaust, but that has made no difference. Can anybody suggest what might cause this? Thanks

 

[JerseyNeil]

I asked a similar question recently regarding a surge during deceleration on my 2010 GS.

This is the reply I received;

http://www.ukgser.com/forums/showthread.php?t=339029&highlight=deceleration

However it does not explain why your did not do it prior to your service.

Neil

 

[Bendy toy]

My Mk2 with aftermarket exhaust does not do this though it does pop and bang on engine overrun. Its not remapped so I dont drive it slower than 2000 revs and keep the revs above 1500 as a I slow down. Both well above tickover speed.

Can a sticking flap valve cause or hide this issue? If its flipping open/shut (hunting) too much the exhaust back pressure will change and affect the engine braking.

Maybe the valve was sticking, but with servicing and lubrication its now moving. Maybe its moving better but is stiff and slow.
Here's an idea - Set the flap valve wide open and disconnect the cables. If it stops the problem you know what to tell the dealer.

 

[GSgirl]

Thanks Neil! Bendy, good tip, will try that next see if that is the culprit, thanks.

 

[tugboat]

None of my bikes have exhaust flaps or injectors.

Life is simple, tum-de-dum..........

 

[JerseyNeil]

And oh so dull Tugboat...................................

Where is your sense of adventure. The thrill of not making it back from your tour without the aid of a tow truck!!!

Neil