Bogging on Throttle issue

[EdStoke]

Hi everyone,

I'm looking for some advice on my 2004 BMW R1200GS. I've been chasing an issue for quite a while now and would really appreciate any advice I can get so I can atleast get some riding in before winter kicks into full gear. I've replaced the clutch and the it goes into and trough all the gears.

Symptoms​

• The bike starts and idles normally.
• As soon as I open the throttle, it bogs badly and often stalls.
• Once it starts bogging, it won't rev cleanly.

What I've noticed is that when I put the bike in gear, most of the bogging disappears and the engine revs much cleaner. As soon as I pull the clutch again, the bogging returns.

Things I've checked so far​

• TPS voltage sweep appears smooth.
• Fuel pump voltage has been checked.
• Gear position switch has been investigated.
• Wiring and connectors have been inspected.
• New Battery

Other observations​

I'm not ruling out any electrical or ECU-related fault.

At this point I'm wondering if the problem could be related to:

• TPS or its wiring
• Clutch switch input
• Gear position switch
• Fuel delivery
• Ignition
• ECU or wiring fault( it seems to look okay)

Has anyone experienced similar symptoms, particularly where I'd really appreciate any suggestions on what to test next.

Thanks in advance for any help.

 

[botus]

do the coil test idea steptoe keeps saying

the main ones die


You disconnect the connector at the top coil on each side. Then start the engine and see if it runs on just the bottom spark plugs.
It'll be obvious if one of the top coils or both have packed up.

You then reconnect the top connections and remove the bottom connections off the the coils, and see if the engine runs on the main coils.
It'll be obvious which, if any have failed without any faffing around.
Start to finish takes 2 minutes.
And no need to remove any of the rocker cover plastics as the coil caps don't need to be removed to do the test, the coil connection/plugs can be unpluged with all the covers in place



if that pans out check fuel pressure

 

[EdStoke]

do the coil test idea steptoe keeps saying

the main ones die


You disconnect the connector at the top coil on each side. Then start the engine and see if it runs on just the bottom spark plugs.
It'll be obvious if one of the top coils or both have packed up.

You then reconnect the top connections and remove the bottom connections off the the coils, and see if the engine runs on the main coils.
It'll be obvious which, if any have failed without any faffing around.
Start to finish takes 2 minutes.
And no need to remove any of the rocker cover plastics as the coil caps don't need to be removed to do the test, the coil connection/plugs can be unpluged with all the covers in place



if that pans out check fuel pressure

Thanks Botus, that was one of the first things I tested, and It seems to be in good working order. I hope is not the ECU.

 

[botus]

a few ideas...

good clean fuel ? - I run BP97
do a compression check - both should match each other, and with say 8 second cranking hit good high pressure - I guess 160psi (if less than 110psi that's bad and >10% between pots, is bad)
is the valve timing correct
remember - rare - but the early bikes did things differently with a different pump and different fuel level set up
is the air filter clean and air inlet 100% clear
are throttle body's clean and opening fully and together
you have a pressure gauge on the fuel system and its bringing the pressures we need
you are aware of the silly fuel pump controller, operates in one of two modes - round town low rev moped mode - large openings, wake up and turn the pump on properly
when did you last replace the spark plugs and swap the ignition coils - mine we playing up at 20k miles I swapped all 4

 

[Santa-2512]

Thanks Botus, that was one of the first things I tested, and It seems to be in good working order. I hope is not the ECU.

Have you had your throttle bodies balanced?

Are the butterflies seated correctly & both opening at the same time,

When was the last time you had them synced & balance checked

oh and are the little black caps on the air feed tubes on the TB's and if the are , are they intact ( no splits )