Was riding last night when ...

[angellr]

I have noticed lately that when trying to "goose" the throttle out of a situation that even at speed there is almost a hesitation (sort of a temporary cut out of power) and then it kicks in. I was trying to get around a car last night when this happened again. Any thoughts of what might be causing this? I have an '07 R12 with roughly 50K miles.

[towerworker]

How long has it been since you replaced the fuel filter?

[websterize]

How long since your last fill-up? Uphill?

I've had alarming power loss while spiritedly accelerating on an incline when low on fuel.

[angellr]

How long has it been since you replaced the fuel filter?

Its probably been awhile since the fuel filter has been changed. I filled up the tank some 100 miles or so ago.

So, the next question, is it relatively easy to change the fuel filter? I have not searched yet, but will be doing so right after I submit this post.

[redwing]

Got this exploded view from Max BMW (below); also there is http://www.realoem.com/bmw/select.do

I'm pretty sure the tank will have to come off. And my mechanical experience on this bike is almost none.

[angellr]

Thanks!! Had the tank almost off the other day when I installed shocks, however, am not sure how to remove it without breaking something. Once again, another search is underway.

[sjbmw]

try 4 oz of seafoam in your next tank full

[angellr]

try 4 oz of seafoam in your next tank full

Thanks Herb.

[hjsbmw]

Thanks!! Had the tank almost off the other day when I installed shocks...

And the hesitation to accelerate started after that? Might be worth a good look to double-check you didn't pinch or kink anything.

[angellr]

Thanks!! Had the tank almost off the other day when I installed shocks...

And the hesitation to accelerate started after that? Might be worth a good look to double-check you didn't pinch or kink anything.

Good point, Harald. This all started happening AFTER I installed the shocks. I guess it will be time to recheck (although as I recall, it was a tight fit under there ... maybe some good lighting can hopefully help me out ... could have a hose thats disconnected?).

[hjsbmw]

Good point, Harald. This all started happening AFTER I installed the shocks. I guess it will be time to recheck (although as I recall, it was a tight fit under there ... maybe some good lighting can hopefully help me out ... could have a hose thats disconnected?).

Are there hoses you have disconnected that you may have forgotten later? I'd religiously check anything under the tank you have touched during that install. I have not had problems with the fuel system on this bike, so I have no idea what could cause this. I'd guess a pinched vacuum hose or breather hose, kinked fuel hose,... Could disconnecting/improperly connecting the carbon canister do this?

[angellr]

Good point, Harald. This all started happening AFTER I installed the shocks. I guess it will be time to recheck (although as I recall, it was a tight fit under there ... maybe some good lighting can hopefully help me out ... could have a hose thats disconnected?).

Are there hoses you have disconnected that you may have forgotten later? I'd religiously check anything under the tank you have touched during that install. I have not had problems with the fuel system on this bike, so I have no idea what could cause this. I'd guess a pinched vacuum hose or breather hose, kinked fuel hose,... Could disconnecting/improperly connecting the carbon canister do this?

I will also double check the hoses in/out of the canister. It runs fine, except for the "intermittent" sputtering. I will probably try Herb's remedy first to rule out bad gas. Normally around here in SLC is not a place where you can regularly ride during the early days of February.

[deilenberger]

If you pinch the vent hose off under the tank you will pull a vacuum on the fuel tank, which can cause this sort of behavior.. This is the vent hose that goes to the charcoal canister (if your CC hasn't fallen off like mine did [with some help..]) There are two other hoses going to the canister - one is an overflow hose (if you drastically overfill the tank and raw gas goes down the vent line..) that goes to the ground, the other is the vacuum line hose that connects to the switching valve that puts engine vacuum on the canister after the bike warms up (to pull the captured hydrocarbon goobers back into the engine and burn them.)

You can ignore all this if you live anywhere besides the US - the canister is a US only "feature"..

Oh - Eilenberger's law of Troubleshooting: "Look where you last worked.."

[Graf]

Hi...you may want to see the story that I describe in this post viewtopic.php?f=20&t=19277

Hope this helps...alex

[angellr]

Thanks Alex, will also consider this as a possibility. It still feels like a short burst of "bad gas" ... but it happened yesterday under hard acceleration into 5th or 6th gear.