The past month or so, I've been seeing consistently less fuel efficiency. No change in riding habits and such and no new mods. I was routinely riding over 90 miles before the fuel reserve light would turn on but now it's been coming on at around 70 miles. Maintenance is up to date and I'm that a**hole who checks his tire PSI before every ride.

 

any change in personal nutrition habits?

 

Yes, they've lead to me being more handsome and brilliant than I was prior. But body weight hadn't fluctuated.

 

if the bike has an O2 sensor it will more or less self calibrate to account for anything going slowly astray in fuelling during the usual part throttle/cruising use so one explanation could be change of throttle use out of this envelope, which you would surely be aware off
so
I guess you have no O2 sensor and something started causing richer fuelling

 

I don't think US-market F4i's had an o2 sensor, or it was removed by the previous owner with the Yoshimura exhaust that was installed.

 

I know Cali models did and I know my '06 did. Something ain't right there but I don't know enough to guess.

I know mpg can fluctuate quite a bit within the same models and I could routinely get 120 miles before my reserve light started...

 

I have a 2001 model. This weekend will be abnormally warm so I'll see how it goes.

 

I know mpg can fluctuate quite a bit within the same models and I could routinely get 120 miles before my reserve light started...