I'm intermittently losing power on my FXCWC when the fuel is getting low. It quickly loses power for a few seconds on straight road, and gains it again right after. No other symptoms.

I have 380km on the same tank. The fuel warning light is on, but the 50km warning hasn't popped.

This is a very recent occurrence with the last two tanks. First time it happened was right after I picked my bike from maintenance. Rear wheel bearings gave out after 20,000 km at the most inconvenient time, but that's another story.

Any idea what is the most likely culprit? Should I get the fuel pump or fuel gauge checked? Not entirely sure how many km to expect on one tank.

 

The fuel pump is where I would start at. It could be on it's way to the bone pile.

 

If this is happening only when the tank is half or below I would check the fuel lines in the tank. Some of the earlier FI bikes had pin holes develop in the lines and when the fuel level dropped below the lines power loss is the result. Run the fuel level below half then shut the bike off for a few minutes, then put your ear on the tank and turn on the ignition switch and run stop switch to run, don't start the bike and listen for fuel hitting the inside of the tank or a splashing or gurgling sound. If you can't hear anything abnormal do a fuel pressure test.

 

I think it's the fuel gauge, and I was just really low on fuel. 376km on one tank is quite a lot.

I added 5l of fuel, and the gauge didn't move at all, still showed low fuel level warning. When I filled her up, it finally shows full. Perhaps the fuel gauge or level sensor is broken.

I'll keep an eye on her behavior. She's about to get scheduled maintenance anyway, so I'll mention to check the gauge.

 

I had a crack in the fuel regulator body that was leaking air, acted like it was running out of gas, could hear it sucking air wheni turned the ignition on

 

I don't trust the gauge. My 02 EFI Fatboy gets about 40 mpg so I simply zero the tripodometer at every fill-up and start looking for a gas station every 170 miles or so.

 

Floats and ECM estimates are far less than accurate when a tank is low. Your losing power because the motor is starving for fuel. What's probably happening is the fuel is moving around the tank when you brake, accelerate and lean causing it to leave the petcock exposed for a second or two. This causes air to get sucked into your fuel line and causing the loss of power.

 

Funny, I have a crack in my *** and I never run out of gas.

 

Post number 3 is your answer.

 

Fuel pressure regulator/housings are common failures, along with the pinholes in the in-tank fuel lines. My money is on one of those being the cause of the issue...