1150GS misfire but not on the road.

[red rocket]

As the title says I have a 99 1150 GS just under 30,000 ran as sweet as a nut .
Put on a Remus but too load so popped old exhaust back on blipped and revved it as you do and it popped and banged flashes out the exhaust and the strange bit the temp and fuel gauge went blank in timing to the misfire. I left it until today to try and sort it.
Checked various connection blocks the wire from the ignition switch etc and as soon as it hit 4.5 to 6.0 thousand revs it played up bloody near deafened ya the banging.
Now the strange thing is I went for a 5 mile ride revved it hard didn't miss a beat revved it when stationary just the same gauges blanking and backfiring.
Coming home revved the nuts off it sweet as you like took it for a 40 mile ride up to 120 and almost red lined in 5th never missed a beat so any ideas?

It may have been like it months and like most guys don't rev it hard in the shed.

I want to forget about it now and pretend I didn't rev it but why would it play up when stationary but not when ridden.

Cheers Ian

 

[buellzebub]

Probably need to reset the Motronic unit. I'm 99% (but not 100%) sure it's fuse 5 you need to pull and wait a short while. Then replace it, turn on the ignition but don't start the engine, then fully open and fully close the throttle several times. Then take it for a run. That's the general procedure anyway, but someone more clued-up will be along shortly.
HTH.

Mick.

livin' the dream

 

[red rocket]

Thanks for that idea . But would it explain the gauges going blank in time to the misfire etc.
Also why ok on the road and not on the stand ?

Any other ideas

 

[buellzebub]

By gauges going blank do you mean tacho needle going to zero? If so then that is a sign of Hall Sensor failure. The difference between being on the stand and on the road I would put down to the difference in loading on the engine and the corresponding mixture required, which the Motronic will/should be taking care of. Conversely I believe you could equally have had the symptoms the other way round as well as a result of incorrect mixture caused by the Motronic 'learning' the mixture required for the other can.

PS. Personally I'd try the Motronic reset, you have absolutely nothing to lose and you'll suffer no adverse effects either way.
Mick.

livin' the dream

 

[MattW]

By gauges going blank do you mean tacho needle going to zero? If so then that is a sign of Hall Sensor failure.

First post states fuel gauge / temp blank so not a symptom of hall sensor failure.

My gut feeling is a wiring fault / intermittent break influenced by engine vibration - possibly the ignition switch loom.

Also, the motronic isn't capable of 'learning' new mixture settings. It runs fixed maps, set by the cat code plug and adjusted in response to sensor inputs (oil / air temp, lambda etc).

Occam's razor says that you should be looking at the things you disturbed when removing and refitting the exhausts - coincidences are unusual.

 

[red rocket]

Thanks for your help guys. You are correct fuel temp gauge not tacho.
I disturbed nothing fitting a different end can it already had the Y piece.

Hard as I tried to make the misfire by moving and pulling the ignition switch lead nothing.
Logically the only difference to riding it and not is the side stand was down or the under load theory.

I'll try to pretend I didn't rev it when sat still