Lumpy tickover and cutting out after overun

[BlueBird]

A problem with my 05 gs 130k up it,

At times the tickover goes rough and lumpy and when slowing down on engine braking with a closed throttle it will spit back through the throttle bodies and cut out when you open the throttle slightly, this can be tricky when in traffic having to restart it coming on to a roundabout or junction etc,
this is intermittent but getting more frequent and is pissing me off big time it fucking up the low speed use of the bike for me as im forever looking for it,

I've,
done valves,
balanced throttle bodies,
reset adaptations,
new tps,
new throttle bodies,
new fuel pump,
new fuel pressure regulator,
air box sensor,
changed stepper motors,
tried the coils of another bike and seemed the same,
checked everything with gs911.

Next is brand new set of coils but as ive tried another set its a £400 spend and a shot in the dark.

Any ideas from the massive

Mikey boy and Steppers to the keyboard Please

 

[BillWright]

Hi

Two points occurred to me.

How old is the fuel? Unleaded goes flat a lot quicker than the old leaded stuff.

You haven't mentioned the spark plugs. Could one be breaking down intermittently?

Bill

 

[Bendy toy]

Two years ago I had similar problems. Eventually new primary coils solved it. My original secondary coils are still ok - plugs look normal.

Intermittent failing primary coils will cause rich running and stalling. They also do not show directly on a 911. My old black painted coils smelled burnt. The secondaries ( same type) never have but they don't run at engine cylinder head temperatures.

A low cost fix could be to try a pair of three wire stick coils from a car breaker. They won't fit the bike engine but could be connected with a patch lead and HT leads.

Usual caveats apply.

 

[BlueBird]

Hi

Two points occurred to me.

How old is the fuel? Unleaded goes flat a lot quicker than the old leaded stuff.

You haven't mentioned the spark plugs. Could one be breaking down intermittently?

Bill

New plugs are fitted and the fuel has just come out of the pump, in the winter I do around 2 tanks of fuel a week.

 

[Greyscout]

Have you checked the readings from the lambda probes, do they match? Perhaps one is breaking down ?
When you changed the throttle bodies did you change the injectors too or use your old ones ?

 

[Bendy toy]

When my plugs were failing (mild misfire) the lambdas got badly sooted up. One coil began to break down then the other one followed closely behind. Both failed within 50 miles of each other.


Sent somehow.