2011 R1200GSA Acceleration Issues

Good Afternoon Sir's/Ma'am

Hope you keeping safe during the current climate.

Im military and still in work, my commuter bike is giving me issues.

2011 R1200GSA with 18k Miles.

Bike pulls very well through all gears until in 6th and on motorway at 80mph, accelerating from there seems very strained and held back, have ridden a r1150r and that pulls much better than mine.

Fully serviced and valves and TBs checked and synched.
Fuel controller and fuel pump replaced.
Injectors replaced
New battery
New primary coils
Bike will start and ride till 40mph on secondarys.
Brand new plugs all round.
Fuel is new
Vent hoses clear
No kinks in fuel lines
TPS swapped with good one from working GS
Adaptions reset on GS911
02 Sensors seem to swing between 0.3 and 0.8 but have been up to 1100mv?

Bike has a akropovic full decat system installed.

I bought the bike, babie dit home as been stored 12 months, fitted exhaust an dthen did a major service.

Had the flat spot issue since owning it and have slowly replaced all parts as listed above to no avail.

Swapping back to stock exhaust tmrw and buying new secondary coils seems my last options.

Any help greatly received.

Have a gS911 log from a run if anyone is well swept up on the values contained.

Welcome to the forum! Lots of smart folks here. I’m sure someone will be able to help.

Thank you very much, have already emailed a log over to a gentleman who seems very knowledgeable and hopefully he sees something amiss.

Any update?

You may have a fuel supply issue at high loads.
At this point I would rig up an inline adapter setup using M&F quick disconnects and a pressure gauge.
You are looking for 4 bar normal running.
Go out on a road test and flog it while watching for a drop in fuel pressure.

If so, there could be an issue with
The pump controller
The primary filter sock
The hose from the pump output to the upper filter chamber (crack)
The upper filter chamber clogged






My rig

GS Addict, Sir, thank you for reply.

I have a new pump, controller coils etc out.

I took pump out again and rigged power to it without controller was showing 130psi, 100 psi with controller connected.

bike running and idling the psi was 60, dropping to 54/55 and high speeds.

so looks like 4 bar and dropping to 3.5 and the top end.

The bike should stay at 4 bar at all times im assuming?

only thing left is the "hidden filter" has clogged?

I back flushed it but with 18k on the clock the cleaning fluid/petrol ran clear, no gunk at all.

So internal housing must have collapsed as stood in storage for 16 months.

Could i have your thoughts, as a new housing is 450 dollars.

Lastly, running without the fuel controller, pump obviously at 100% and that made a noticeable difference, as well as my brothers F800GS fuel assembly loosely inserted into tank.

Both these times the bike seemed to pull strongly to 7k

lastly Sir, did a flow test off the right side disconnect to a bucket, I was getting 570ml in 30seconds.

The above all looks good IMO.
I'm not concerned with 3.5 bar at top end - plenty of pressure for the injectors.

Also good.

Then I am very much stumped.

Drop in pressure was only thing that was highlighted in all the tests and gs911.

Only way I can make the bike accelerate better is disconnecting the controller or someone elses pump housing.

I'm at a loss

If your sucking jet pump isn't working you may have a fuel return problem.
https://parts.bmwmcofpalmbay.com/a/...3759/Sucking-jet-pump-with-lines/16_0581.html

Hi Sir, sucking pump is fine, and clear. My issue is the bike seems fuel starved at high rpm. 6k for example, bypassing controller and a diff housing make sit run much better.

only logical thing is that the hidden fuel filter has collapsed or partially blocked.

already cleane dit and the fuel/cleaner mixture was clean as a whistle. so much be collapsed etc and strangling the flow at high rpm as i see a 1/2 ba drop in fuel pressure at wot

You've already swapped in a borrowed or replacement fuel pump, and the bike then ran "strong" as you expected it to at higher rpm?

Here in the States, we can get those pumps for only about US$150...

https://www.euromotoelectrics.com/product-p/fp-379.htm

That's a relative bargain compared to BMW's list for the whole assembly. Shipping affects final cost, however. Does Nippy Norman list anything similar? Motobins, etc.?

the pump is brand new, the actual housing with locked away filter is the 450$ issue. the pump on my assembly is new and tested at 130 psi.
with fuel controller bypassed the pump is at 100% at alll time so negates my symptoms, say 50%. another whole assembly make sthe bike run very well.

only thing left in the problem equation is the filter in the assembly

Normally I cannot see 1/2 bar starving the system for fuel, but when checking my reprom specs it shows 3.5bar operating pressure for the Hexheads and 4 bar for the Camheads.
Something to add to the list.

yes this is also what it noted, hence bike runs very well at rpm till 5500ish then when i open it at say 80 or 90 its slowly pulls to 110 etc.

my 1100gs pulled better at higher rpm, so definitely starvation.

If I'm reading the above correctly, then I'd try bypassing the FPC with either the dongle that Burns Moto sells or else a length of paired wire. Who am I kidding? I'm cheap and would go with the paired wire.

And if the bike runs as desired / expected with the FPC bypassed then either the FPC itself is bad, or else the wires (2) between the FPC and the fuel pump are the problem. But maybe I'm misunderstanding the swap & testing discussed above.

i ran the bike with the FPC bypassed, with wire, and it ran better. good shout on the wires running through housing. can check them out. but unit has 18k and looks clean as a whistle, but a look over and continuity test might be worth it

only thought is that why the wiring is only breaking down at higher rpm only, but maybe some corrosion.

Just thinking this thru more...
Any chance the baffles/packing have come loose in the AK silencer?
Do you still have the stock system to test?