Hey guys, I have had this f4i for a while and its always gotten subpar mpg. i believe at the most, 25 mpg. I run 87 / 91 and cant really tell a difference. this is a CA bike not sure if thats relevant or not. does have canister on the bottom though.

Anyways a while ago when i was riding I had the 4 bars of reserve come on, and then bike was stuttering then quit. Had to keep starting it up and revving it like crazy to get momentum to roll up a hill and ended up having to push the bike.I managed to get gas from some gardeners on a side strip from the main road and it started right up of course.

also in regards to mpg ive tried checking tire PSI, air filter is clean. not sure what else to check, brakes arent dragging and doesnt seem to be misfiring. occasionally at a stoplight if i dont rev it up it will bog on takeoff.

Any ideas let me know! Thanks alot!

bike has coffman shorty exhaust from P.O. not sure if this is a huge factor or not but thought id mention it

 

@xifer Have you checked to see if there are any FI codes in memory? Does it have a Power Commander on it? 25 MPG is terrible.

 

Wow, that is really bad....
Can you let us know as Dirt suggests how is the bike set up. The shorty should not affect it too much, if anything might get it to run a little lean.
It might have something to do with the CA emissions set up but I do not have any knowledge of that.

 

The only difference between CA and the rest of US emissions is the O2 sensor and a charcoal canister for fuel vapor, so no thats not the issue. The fact the bike stumbles on acceleration sometimes is the clue something is up running wise. My bike is down to like 35mpg these days, I used to get 50 when it was new [and so was I haha] but I have a lot of miles on it now. And yes, the reserve gauge has never been very accurate.

 

That did make me laugh, I guess we all get a little out of spec as the years go by

 

Is that normal, i.e. for mileage to drop over the life of the bike? Just curious because mine was bought with just over 8,000 miles on it but has never gotten over 35-38 mpg, unless I'm putting along and being very light on the throttle. As for the reserve, it does seem as though everyone's is... unique!

 

I usually get about 34 on mine and 've got about 18k on it. It could be slightly better but my re-gear runs the RPMs up a bit.

 

25 is not very good. Check your spark plugs, valve clearances, and fuel pressure regulator. I'm assuming you are not running a PC.

Doc, does being light on the throttle help? Mine seems to get better when I'm on the throttle a bunch. They are mapped for high rpms, so.....

 

I still appear to get 45-50 out of mine (which is probably about 40 in US currency! ). The custom map on my PC helped a lot with the fueling at the lower Rev ranges and I do not tend to rag it all the time.

 

It does... significantly. I'd say 80% of my riding sees the tach between 5-8k. When I go into low speed cruise mode I can get close to 50 mpg. On track days, I'm down around 30 mpg...