Perplexing Surging Problem with 1150 RT

[jeinloes]

I have a 2003 1150 RT with 50,000 miles on it. Last August, it began surging in all RPM ranges and at all speeds. The dealer found the fuel pressure at 4.3 bars (maximum is supposed to be 3.2). He replaced the fuel pressure regulator. At that time, I also had him install a Techlusion FI 1032. He also replaced the plugs, but he did not replace the fuel filter, which has never been replaced.

My mileage has been averaging 36mpg to 38 mpg. I used to get between 41 mpg and 46 mpg routinely. I decided I would disable the Techlusion to see if that was affecting the mileage. What I experienced with the Techlusion off was the same surging in all RPM ranges, just like I had before replacing the fuel pressure regulator. Mileage with the Techusion disabled was 39 mpg.

I have run Techron through the system, thinking that I may have a clogged injector. The bike runs better with the Techlusion, but it is still not running as well as it did before the problem surfaced. I think the Techlusion is simply masking the underlying cause.

I would appreciate any advice regarding what to do next.

Thanks.

[bikerfish1100]

why have you (and apparently your dealer) elected to not replace the fuel filter at its recommended mileage?
i would do that as a first step so that is no longer part of the equation.

[jeinloes]

I agree. And I was a bit curious as to why he didn't replace it when he replaced the fuel pressure regulator. He seems to think the the fuel filter would have little to do with this problem.

[lazywizard02]

Adjust the valves and balance the throttle bodies. That, with a clean air filter/fuel filter should be the fix.

Examine the throttle cable path and connections for ease of movement and correct connections.

[bikerfish1100]

He seems to think the the fuel filter would have little to do with this problem.

I agree that it is not a likely culprit, but even so, it just makes good sense to remove the possibility that it is somehow involved. plus- at 50K, it is twice past due for its scheduled change. or does your mechanic create his own maintenance schedule that differs from what BMW says is appropriate? :scratch

[riderR1150GSAdv]

IMHO, the fuel filter should have been replaced twice over already. This could lead to partially clogged injectors leading to incomplete combustion....and downhill engine operation from there.
Check valves, do a TB Sync replace fuelfilter and clean the injectors, professionally if needed. I doubt that a techlusion was needed in the first place..YMMV. Just 2 pennies here

[jeinloes]

That's exactly what I'm going to do.

Thanks!