Fuel economy question
 

Hey guys. I believe to have a problem with gas mileage on my f4i. I've measured the mileage from 0 at a fill up and got 106 miles when the fuel reserve indicator has turned on. Isnt that weird? I've done some research and read up posts in which guys are talking about easily getting 180 miles on a full tank. Should I be worried?

Well there's only 2 reasons for that low miles per tank: she's really drinking that much or she's only "reporting" it.

There's actually a lot of guys that had problems with the fuel pressure regulator going bad ( do a quick search for FPR ) and a few others with the fuel reserve sensor in the tank.

Next time that you fill her up take notice of the amount of fuel that you actually put in. If you put around 14.5 liters she's reporting ok and it probably is the FPR.
If it shows the reserve bars and you put let's say 10 liters, then it's the fuel reserve sensor.

That seems to me like it's a bit of variation in riding. So you got 70 miles less than the guys that SQUEEZE 180 out of their F4i. If you ride politely all the time, and don't exceed 5,000 rpm, you'll also get 150 miles out of your tank. Try to ride at your easiest, and see if you still get 108 miles out of your tank. If you consistently get 108 or 110 out of your tank, and you're being very gentle with it, then I would look into the FPR. My F4i got about 140 to the tank with some spirited riding, but not out of control. I would take an average first, not just go off of one tank of fuel.

Another thing to think about is your mods. If you are geared, or have a slip on, stacks. etc. Some exhausts require a tune so the bike doesn't run rich as a pig, which I'm sure you know seeing as you've been on here for a while. So make sure it's not just an easy maintenance thing before you go replacing FPR's and various sensors.

To answer your question: No, you should not be worried. You're not throwing any CEL's (that you mentioned) and 108 isn't THAT bad. Could be something easy, could be something deep. But at 108 to the tank, you're getting ~22 miles to the gallon. Try a different fuel (premium if you don't use it..), and ride like your 76 year old neighbor on their Vespa, and see what happens with MPG's then.

+1 what Junior said. Right now I would say you don't have a MPG issue. Some will claim they get 180-200 miles before fill up and others only get 100. You're not too far from me and I never thought I had a MPG issue. I would say if your getting 80 miles then you have a MPG issue.

Thank you for your input guys. Every time I get about 110 miles BEFORE the reserve indicator kicks in. And yes, I've been using nothing but the premium fuel. As far as riding goes, I tend to do 6-7k of rpms on the freeways. I was also wondering about how to keep the rpms and whether it's better to keep them high with a lower gear, or low with a higher gear.

As a side note my bike runs better on 87 octane than 91.

what do you mean by 'better'? 87 is a dirty fuel i would say, since it does not burn as well as 91 and leaves more residue in your engine. am i wrong?

Yes, you are wrong. 87 actually burns more easily than 91.

The difference between 87 and 91 is not the quality of the gas but their ability to ignite. So 91 is harder to ignite that 87. Motors with high compression motors use 91 or higher because the high compression has a tendency to prematurely ignite lower octanes. Try to put 87 back in and see if you notice a difference.

As far as RPM's go I will always choose a lower RPM in a higher gear while cruising. The lower RPM will give you better fuel economy and it is not harmful to your motor as some think. The only downfall is your not in the real high RPM where all the power is in these 600 so when you punch that gas it might not take off like a raped ape but it should still be plenty enough especially to pass a car as long as its not a Z06 Corvette or Viper.

I used "better" for a reason. It is very generic and based strictly on my opinion. As they say "we all have one and it dont stink" :) Their are so many variable involved in my "better" feeling that I couldnt possibly cover enough of them to convey my feelings into facts, I leave that to the liberals :) Lets just say that during the summer when I first got this bike I used 91 exclusively. As I gathered more info here and the manual I realized this bike was built to run 87 so I tried it and the bike just "felt better" and was to spec and is cheaper. Whats not to like :)

Oh yea. My rule of thumb is that if it dont knock you dont need higher octane. Especially if you live in cold conditions. Much more difficult to start the engine.

http://en.wikipedia.org/wiki/Gasoline
http://en.wikipedia.org/wiki/Oil_refinery

Same refined product with a anti knock additive.

This is one of those examples of when learning is fun and will be with you the rest of your life.

Thanks a lot, Mitch :)

BTW that is one awesome looking ride.

Thanks :) Anyway, isnt the change of fuel going to be harmful for the engine? How should I do this to avoid any complications?

As some of the previous responses alluded to, it sounds like you are jumping to a conclusion that you have a mileage issue, but we don't yet know what you are even getting for mileage. How many miles you get before the fuel light comes on doesn't necessarily tell you much. (Just like calculating your mileage based on the fuel gauge in your car isn't accurate and isn't very useful). We need to know how much gas you are putting in when you fill the bike up.

If you are putting in 4 gallons, well, then you may have a problem (as that would be around 25 mpg, which isn't so good (at least, not for a stock bike. If you have chopped your exhaust off and are running a rear sprocket the size of a pizza pan, then 25 might be just right!).

On the other hand, if you are only putting in 2-3 gallons, then the mileage is fine. If that is the case, then the question is why are you only putting in that much gas. It could be an issue with the reserve light coming on too early, so you've still got 2 gallons left when it comes on, or it could be that you aren't filling the tank up all the way.

On the F4i, there's a little metal bar that runs across the inside of the tank, and you can fill it up to that bar. If you are sticking the pump into the tank all the way, the pump will shut off early. I usually put the nozzle under the 'uphill' side of the opening and let it run, then pull the nozzle out and top it off to right around the little metal bar.

I've never put more in than 3 gallons. I rely on the pump itself to distribute the gas until it cuts the gas on its own. I guess I havent been filling the tank all the way, but thats b/c I dont want to overfill and have issues afterwards. Yes, I've seen the metal bar and I didnt know that I could use it to fill the tank up all the way. Thanks for the info. I'm glad to learn something.

There is your problem right there. You can't rely on the pump when using a bike, because the nozzle gets buried in fuel. You have to sit on the bike, hold it up straight, and pour in your fuel gently (and watch for it to touch the silver metal piece). The F4i tank is like 4.5** gallons when bone dry (somebody feel free to correct me), so just watch it yourself. When you're done filling the pump should say almost 4 gallons!

4.9 fully dry. I fill to the bar and get between 140-150 miles before the reserve comes on. I should have .9 gallon left by then but fillup only needs a little over 3 gallons.

If you doubt your MPG, get an app for your phone. I use aCar on Android phones to track MPG & maintenance. You just enter the odometer and gallons at the pump. You set up alerts by mileage and time period for maintenance routines (like 4k miles or 6 months for oil change).

It'll tell you exactly what your MPG is. Mine is about 28 MPG... but then again I usually don't shift until 7k-7.5k... ever :p

Here's a link to the Android app. Pretty sure there's prolly 20 similar iPhone apps: aCar - Track your vehicles

106 miles on 3 gallons is 35 mpg. Your mileage is fine. It sounds like your problem lies elsewhere as others have suggested.

There isn't a problem. He was concerned with his fuel economy, and we got it figured out. Case closeddd.

Thanks for being the first one to post that. I was beginning to wonder if no one knew how to calculate mpg. When someone is concerned about fuel economy their mpg is the first thing they should have posted. It took to the end of the second page of replies before anyone got a round tuit.

http://i3.squidoocdn.com/resize/squi...roundtuit1.jpg

I can change the word problem to issue if it makes you feel better.

I was simply stating that it sounds like there is a problem and it is not fuel economy. That was never explicitly stated before my post.

That's because it took until the middle of the 2nd page to find out the numbers needed to make that calculation...

lol thanks guys. i've put 3.688 gallons today when the reserve indicator was at full stage. is that about right? i will let you know of the real mileage once i burn it all. oh, and for the first time i've put the 87 octane gas in.

I am assuming that when you say full stage you mean all 4 bars are flashing correct? If so you still have over a gallon left. The tank holds 4.76 gallons and the reserve indicator comes on with about .92 gallons left. However once it comes on the mileage determines when the next bar flashes so it is not a accurate read of what is left in the tank. I don't know of any F4i where the fuel gauge is 100% accurate.

They are not flashing, but staying put.

Then it's not quite on E. When you have all four solid markers there, your bike is telling you that you're down to your last gallon (.92 of a gallon to be exact), and from there, the markers will delete themselves one by one. When they all blink or flash, you're about empty, and it's time for a fill up. However, the 3.xxx gallons you put in is pretty close to a full gas tank when those lights come on. Maybe next time, if you're SURE there will be a gas station within 20 miles, ride until they blink, or get down to one bar, then fill up. But like I said, I think this case is closed.

Easy killer. That's why I responded to you that way. You're stating that you think there is a problem. But, there are countless other members in this thread that say, "fill all the way up, and try again" or, "use different fuel." Posting up generalizations about the OP having a problem with his bike might lead to confusion, or him taking steps that don't need to be taken yet. He's already stated that he used different fuel, and that he put more fuel in the bike. Ya see, it's all about them baby steps.

So, in essence, changing "problem" to "issue" isn't going to help either, because it's still neither of the two. :)

the man is right. it has been a problem/issue to me until i got educated by you guys. this forum has been very helpful to me so far and im proud to be a member.

I know boss! We're glad to have ya! Haha, I was trying to detour the idea that your bike might have a PHYSICAL or MECHANICAL issue. I wasn't trying to be mean or condescending to him; just didn't want you taking unnecessary steps to fix it when it ain't broke! Ya know?!

What are you doing on here?! Go ride and run your tank down like I asked you to! :)

Lol im about to head out :) thanks again!

Good man! :) Be safe.

i skimmed threw and didn't see anyone post about sprocket change.. i had millage and running rich problem when i first got my f4i and it was the fpr..
after i swapped to the 600rr swing arm i changed my front sprocket to -1 so the chain would fit.. i noticed big difference in rpm on highway and millage went down a bit too.. i have read where people doing sprocket change to -1 in front and +2 on rear.. to me seems like you would waste more gas than it would be worth.. i have another chain and am going back to stock gearing.. i'm not a racer and the bike is fast enough on take off for me...

Nobody mentioned gearing because USUALLY the owner of the bike has done his research and knows what will happen with a gearing change, and the OP didn't mention anything about a sprocket(s) so I guess we ignored it. Good suggestion though!

PS- I agree. Stock gearing is just fine. With a sprocket change, you can't go on any long rides or enjoy a simple cruise the same way you can with stock sprockets haha.

Ok so yesterday I had the fuel reserve indicator come up at 146 miles. As a reminder, I've put 3.688 gallons before. I've also noticed quicker starts with the 87 octane gasoline.

What was the mpg for that tankful?

well, i only know that i was able to do 146 miles on 3.688 gallons, which would give me roughly 39.58 mpg. also, i've been trying to ride carefully not exceeding 5k in the city.

sorry if this is partly off the subject at hand...
I've been running 93 octane since i bought the bike (it's also what the PO said they ran). i know that one time i had to get gas the station only had 92. (I also realize the owner's manual says it's designed for 87). so, i figured 92 shouldn't make any noticeable difference, but the bike seemed to run really rough on it, so I've been afraid to run 87.

all that being said, i was wondering how response of the bike has been on 87 compared to 93??

here in CA we have 87, 89, and 91 octane fuel. i used to always get 91 until recently when i've switched to 87 and i notice a slight improvement in engine response and start up. hope this helps.