Hi guys,

My f4i has been giving low mileage for 3-4 tanks now. I recently measured it more accurately, I'm getting ~34mpg (this was mostly highway/fast suburban roads). Earlier I used to consistently get ~45, even in city.

I removed the vacuum hose on my FPR to check if it was leaking, but there was no fluid output from that.

I currently have no driveability issues. After a tank with seafoam the bike's been running very smooth! However it has so much reserve performance (and an electronic brain) that I suspect the problem is being compensated for without any symptom other than the mpg (I rarely get even close to using ~100bhp :P).

I'm at ~12k, have changed the air filter but not the sparks. Oil change was also recent (~1k mi).

How should I debug this?

Thanks in advance!

 

what was the last thing that you did before this started to happen?

from 45 to 34 is a very drastic drop. pull your plugs to check the gap and see how they look.
you have an O2 sensor on the bike?

 

I dont have an O2 sensor. Last thing I did before this happened was probably change stator cover and oil after putting it down
I do believe though that this problem started a little after the change and not immediately (hope)

Guess I could change the plugs since they'll need change after 16k anyway...

 

Has yoru riding style changed much? I have noticed a big drop like you are mentioning, but I relate it to me getting more skillful and staying in the power more on spirited rides, ro even my ride to work, I tend to take off a little faster and ride more agressive.

 

Have you been ridin with your RPM's up between 55-65k since readin the post at the end of the summer, like mentioned before. My milage went down as well especially after adjustin my riding style, From that of an Old Woman that is.

 

It's possible I take off a little more agressively now, that's about it though. 45 to 34 _mostly highway_ is the drop I was mentioning.

Changed my plugs, but the old ones are all within spec, and although the front end was covered in brown liquid, the tip and sparking point were clean white. (attached pic 1)

On one of the coils though, I noticed some brown fluid though... (see attached pic 2). Sorry the picture is out of focus, but it shows the area which had the brown fluid coating. Should I be worried about this?

I hope the pics are ok...

[IMG]local://upfiles/11015/52EF9A4238774C23AEB7FD4CAFD6248E.jpg[/IMG]

[IMG]local://upfiles/11015/FA2231A71B6245EF9416C7F93EDD0ADF.jpg[/IMG]