Honda CBR 300 Forum banner

Better mpg help plz

27K views 56 replies 21 participants last post by  atown8605  
#1 ·
I just bought a cb300f about 3 weeks ago and have about 300 miles on it (bought it with 3 miles) spring showers are keeping me off it right now.

I do 34 miles round trip to work about 32 of those are highway miles at speeds of 65 to 70 and I'm only hitting about 52 mpg average. I'm wondering if that's because I'm still in break in window or cause of the high rpms or both. I'm not looking for a fast bike that's why I have my Evo I bought this bike cause of the gas mileage but seem to be hitting low. I had a ZZR600 that hit 45 to 50 mpg so can't figure out why that's all I'm hitting on a 300. Any help will be appreciated.
 
#2 ·
Your mpg is on the low end according to FUELLY:
2015 Honda CB300F Mileage
I think it will improve as the motor breaks-in but I get my worst mpg on the highway.
After 600 miles you could try a 15 tooth counter shaft sprocket.
Looking at results on FUELLY you probably wont better 60mpg hiway. Your ZZR600 was more aerodynamic so better hiway mpg.

BTW: I really like the 300f. Excellent urban bike.
 
#3 · (Edited)
I never hit above 50mpg until recently, with 3k miles on.
In fact, some of my first fuelups where 45, 25, 38, and 44mpg. The 25 was after more than a gallon of fuel had evaporated over the course of 1 week just standing in the sun.
The cbr needs to pass at least 1k miles. Then it only gets above 60mpg if you keep the speed below 60mph.
I may actually hit 66mpg this time.
The higher the speed, the lower your mileage.
You can do 2 things,
1-change sprockets. Change them to 15t front, 35t rear.
2- use a fuel controller in combination with an open exhaust and k&n airfilter.

The first one will raise mpg by about 10%
The second one was a big one for me, because it allowed my bike to rev from 3k rpm instead of 3.5k (or accelerate fast from 3.5k instead of 4k).
The drop in rpms allowed me to ride at 30-35mph in 6th gear, as opposed to 4k in stock 5th gear.

You need to change your stock oil at about 600 miles (I did 300 and 1000 miles), and you're not supposed to do prolonged highway on it until you've logged at least 300miles. (Engine break in).

These cbr and cbfs aren'tvery fuel efficient due to high rpm, and low low rev power.

If you have a black cbr, also make sure you're not parking the bike under the hot sun.
South Florida sun heats up the tank so bad, you could actually burn your hand on it.
I'm currently looking for a tank bag, to protect the tank from sunshine radiation.
The heat makes fuel evaporate through the vent hose, and all models save for Calif models, do not have a carbon canister, but a regular vent hose.
Honda does not recognize the issue, though some other people on this forum have mentioned it as well, and people on the CBR500 forums have complaints about it as well.
 
#4 ·
Put some miles on it, 300 is bugger all and its still tight, get used to how it rides, this is mine, notice how mine is a bit wobbly when i first got it.

CBR300R ABS (Honda CBR300R ABS) | Fuelly

Mine now has 4500 miles on it, I got the 97mpg riding easy all week which was hard lol, one or two low spikes are at 80mph on the motorway, i give it a bit now and then through the week and still get 90mpg usually.
 
#5 ·
Put some miles on it, 300 is bugger all and its still tight, get used to how it rides, this is mine, notice how mine is a bit wobbly when i first got it.

CBR300R ABS (Honda CBR300R ABS) | Fuelly

Mine now has 4500 miles on it, I got the 97mpg riding easy all week which was hard lol, one or two low spikes are at 80mph on the motorway, i give it a bit now and then through the week and still get 90mpg usually.
A British gallon is 1.2 us gallons. 97 brit mpg = 81 us mpg:nerd:
 
#9 ·
I've subscribed to the "run it hard as possible the first 1K miles" theory, for better break-in/mpg for the rest of the life of the engine.

No matter how small the engine, it takes a certain amount of energy (gas) to overcome air drag @ 70 mph. Theoretically the faired CBR300R would get the best mpg, probably around 40-45 mph in 6th gear.
 
#19 ·
I bought my CBR300R just over a month ago. It had 1 mile on it when I got it and hit 600 yesterday. My commute to work is 60 miles round trip. These are not highway miles though. Ranging from 35-55 MPH. I've tracked my fuel mileage from the beginning except the 1st tank from the dealership. I did read on here that the ethanol free gas will get better MPG so that's what I've been using. My 1st fill up averaged 77.6 MPG, 2nd was 80.9 MPG and 3rd was 83.9 MPG. So I don't think engine break in period would be causing it. I'd have to assume it's the higher RPMs.
 
#21 ·
experienced riders going for economy will consciously
and even subconsciously use gently throttle controls..
'everything' is designed for average, good riding..
if you need to take off at the lights etc,
you will use heavy throttle - thus extra fuel..
if not, then you can use minimal throttle
together with gear ratios and time,
to get to the same cruising speed..

even a habit of gripping the bars [for example]
can increase the amount of fuel you are
squirting into your combustion chamber..

a faired motorcycle aerodynamics would be
better for any higher speeds, cutting the load
[air] your available power must push thru..

make sure your tyres are at least, recommended
pressure.. for extra loadings increase pressure,
but also to reduce rolling resistance from tyres
against road surface, which requires more
hp thus more fuel, for the same speed..
[think of pushing a bike with a flat tyre]

not a big thing, but it all adds up
especially at speed over distance..
 
#23 ·
If you are planning on getting a fuel controller in the future, just get the 34t.
I personally liked the 15T front, and 36T rear for the city riding.

A fuel controller will give you that extra oomph on a 34t rear (with a 15t front) on the highway.
Without it still runs nice though.
Any faster than the top speed of the CBR300R, and your skin starts flapping in the wind like a bedsheet on a laundry line.
 
#25 ·
I got 60 MPG out of the first tank with mixed city, freeway and traffic jam lane splitting. I have a 25 mile round trip commute to work 6 days a week. I suspect my mileage will go up as I get smoother on the throttle and clutch, lots of false starts and stalls in that first tank. I'm using 91 octane because the valves are tiny and it's insurance against knock for a few cents per tank.
 
#26 · (Edited)
While I got an average of below 55mpg the way I ride it (above 80mph), my last fuelup was 65mpg going a bit more moderate on the bike.

So I decided to test it out, brought with me a can of gas, fueled her up to the brim, and do my 200 mile everglades tour,.
I tried my hardest to keep her at 55mph, did not exceed 60, and occasionally went slower than 55, very few stop lights.

At around the 100 mile point, (88 miles indicated), my fuel indicator lost its first bar (4 bars left).
I know it had to do with filling it up all the way to the top, more than I usually do.

When I finally came home, the odo indicated 163 miles. Add to that the 13% missing from the gearing change, and my tour in actuality was 188 miles, not 200 miles.

I also still had 1 bar of fuel left, so I never got to try how much fuel it has in reserve.
Usually, when the bar starts blinking, I'm at 2.3 gallons, so doing 188 miles with 2.3 gallons, that's very close to the 80MPG mark!

Picture for reference:
Image


It really defeated the main purpose of my ride, to see how many miles I have in reserve, but at least now I know with moderate constant riding (50mph), I can do about 200 miles (or more) on a tank.

I also would like to see what would happen if I truly run out of gas...
My bottle holds a quart of gas, good enough for 12-20miles.
 
#27 ·
While I got an average of below 55mpg the way I ride it (above 80mph), my last fuelup was 65mpg going a bit more moderate on the bike.

So I decided to test it out, brought with me a can of gas, fueled her up to the brim, and do my 200 mile everglades tour,.
I tried my hardest to keep her at 55mph, did not exceed 60, and occasionally went slower than 55, very few stop lights.

At around the 100 mile point, (88 miles indicated), my fuel indicator lost its first bar (4 bars left).
I know it had to do with filling it up all the way to the top, more than I usually do.
With the tank filled right up to the baffle plate you should have 6 bars showing on the gauge, not 5. And the 6th bar usually goes away fairly quickly, typically by about 25 miles.

4 bars remaining at the 100 mile mark?... not that it really matters, but I would think that at the 100 mile mark you'd be down to about 3 bars remaining. Obviously the fuel gauge is not linear, due to the shape of the tank.

When I finally came home, the odo indicated 163 miles. Add to that the 13% missing from the gearing change, and my tour in actuality was 188 miles, not 200 miles.

I also still had 1 bar of fuel left, so I never got to try how much fuel it has in reserve.
Usually, when the bar starts blinking, I'm at 2.3 gallons, so doing 188 miles with 2.3 gallons, that's very close to the 80MPG mark!
So if you refueled in the past with 2.3 gallons when the last bar started to flash, that means you had aprox. 1.0 gallon remaining in the tank (Honda lists the fuel tank capacity as 3.4 U.S. gallons). However, that last gallon isn't really considered to be a true 'total reserve', as the fuel pump needs close to a half a gallon or so in order to remain submerged in fuel and running cool. So when the last bar begins to flash, you can figure you've got about half a gallon or so of usable fuel to get to a gas station, without putting the pump in jeopardy of running too hot (which obviously will eventually lead to premature pump failure).


It really defeated the main purpose of my ride, to see how many miles I have in reserve, but at least now I know with moderate constant riding (50mph), I can do about 200 miles (or more) on a tank.
So you didn't think to stop and refuel at the end of your ride?... doing so would have told you how much fuel you actually used over that 188 mile distance.

I also would like to see what would happen if I truly run out of gas...
My bottle holds a quart of gas, good enough for 12-20miles.
If you run it completely dry, one thing that will happen is your fuel pump motor will have been running significantly hotter than the temp it is designed to operate at. The other thing that will likely happen, is that the engine can be difficult to re-start after having run the tank and fuel system completely dry.

Which is why Honda intentionally designed the fuel gauge to begin flashing with about a gallon of fuel still remaining in the tank, so as to avoid both of those scenarios.
 
#28 ·
As some members have pointed out, getting higher MPG's with these small displacement bikes isn't difficult. And it can be done without necessarily resorting to changing sprockets for taller final drive gear ratios... one simply needs to be smooth while accelerating & decelerating, and keeping road speeds in the 40 to 55 MPH range in the upper gears. Hard acceleration and running for extended periods at higher road speeds/high RPM's is when fuel economy drops off significantly.
 
#29 · (Edited)
So, this morning, I wanted to go completely dry,
I planned a route of about 20 to 25 miles, but found that the last led started blinking only at about 175 miles indicated (which is 197 miles taking the 13% gearing differential in the calculations).

So I continued my trip, until finally around the 225 mile indicated mark I ran out of time and gave up.
I was expecting the bike to last way less than it did.
It was as if it was pulling fuel from another dimension!
When the last bar starts blinking, on my setup, at 50mph, there is more than 50 miles of fuel left.

I fueled her up, 3.261 gallons.

Here are the pics at the gas pump:

Image


Image


Taking the 13% higher gearing in consideration, the bike indicated 225 miles, that is 254.4miles GPS, and consumed 3.261 gallons.
That is an average of 78MPG.
Not very far off my original estimate, and not bad!

And my $7.5 on gas was well spent (over 6 hours riding pleasure)

I did have more stoplights than before (probably 10 to 15 over the course of the 50 miles).

I also round off the $$$ at the pump, but the fuel was all the way in the neck, just like I fueled it before the trip.

I am running the bike a bit richer than stock with the O2 sensor resistor.
Perhaps I will try to do the same trip another time again without it, to see if my fuel mileage would go up or not.
 
#31 ·
I got 223 miles (358km's) on mine last month when I forgot to fill up on the way home from work. As I pulled into the servo the last bar just started to flash. The only mods on my bike ATM is the slip on and a 15t front spocket. I don't always get economy like that but it goes both ways depending on road/weather conditions.
 
#34 ·
I ride mostly between 30 and 50 mph with no highways. I enter my miles and gallons in a spreadsheet to track gas mileage and after 3933 miles I am averaging 89.1. It was hard to believe at first but this has been consistent over time. I considered a scooter because of my use of a Honda CB300f for around town so am most likely riding as easy as anyone can. I tend to go around 250 miles with the gas indicator starting to flash around 220 miles. The most I have put in at one time was 2.88 gallons and I went 267 miles. I seldom get over 6000 rpm so that helps a lot with this gas mileage number.
 
#40 ·
As long as I keep off of 60+mph riding and stay out of the upper half of the rpm range I usually get between 75 and 85 mpg. My bike is Stock except for projector mod and windscreen. I think if I travel anywhere major out of my normal area I'll use backroads and city streets to get better gas mileage, be more comfortable at lower speeds, and see better sights than the interstate network brings.
 
#41 · (Edited)
Do you have the F or R model? By projector mod do you mean you installed HID bulbs with a projector lens? If you did do you have any photos of it?

Keeping on topic I'll update my MPG again.
13/37 tooth gearing(6th gear@6,000rpm=50mph), hi-flow full exhaust, K&N air filter, Fuel Controller, O2 sensor removed, Pair valve removed, IACV disconnected, took off about 25lbs weight, and front lowered 1.5 inches(I list this because I feel it's more aerodynamic)
80%of my riding is mostly stop n go traffic with lights/stop signs every mile or so at speeds of 40-50mph.
20%of my riding is 50-70mph for 5-mile stretches
No highway riding at all, ever, never seen the highway
Brand new I was using 93 Octane 10% ethanol
Last 3 months I've been using 90 Octane NO ethanol and have found it runs better. Smoother idle and maybe a lil more pep and responsiveness

So if I ride it hard(weekends with my bike group), redlining every gear I get around 65-68mpg
If I ride it smoothly just hopping around town and stores I get 72-75mpg

*I get gas when I am on the 2nd bar and always fill it up. I keep every receipt and calculate every tanks mpg lol(I'm OCD like that)
 
#45 ·
I have the base HID kit, then bought the separate relay harness which connects the HID's power directly to the battery. I was afraid of burning out my stock wiring. So there is an H7 plug that comes off the relay and you plug that into the stock h7 right side headlight bulb. So after I connected those 2 I simply put an on/off switch mounted on my handlebars and spliced it into the relay harness side right after that H7 connection so my stock wiring is still uncut and stock. So this way when the switch is off it's not letting the relay switch on. I just wanted to be absolutely certain there would be zero draw on the battery since I did connect directly to it.
Now I start my bike and in a few seconds flip the new headlight switch and the right side headlight instantly fires, every single time and absolutely no flicker at all