My Honda CBF125 on 150mpg :)
 

Hi there :)

Im Daniel Maia, and im from Portugal :)

Bought a Honda CBF125cc on April of this year, and simply: love it :)

My best mileage was 1.56L by 100km, it means 150mpg :)

Hope you like it :)

https://www.fuelly.com/attachments/fo...4ed333b72f.jpg

https://www.fuelly.com/attachments/fo...c7b78b3183.jpg

Re: My Honda CBF125 on 150mpg :)
 

Looks like a great scoot for city roads in Portugal.. rock on.

Re: My Honda CBF125 on 150mpg :)
 

150 mpg... delicious :)
And this little CBF looks good too. I like it :)

Re: My Honda CBF125 on 150mpg :)
 

Hi Daniel,
Congratulations! Well done, and indeed your CBF looks good. I have the CBF600, but mpg is lower as you can see.
What's your overall, average fuel consumption since you own the bike?

Re: My Honda CBF125 on 150mpg :)
 

Thanks guys :)

i-DSi, you can see it here:

https://www.spritmonitor.de/en/detail/391102.html

:)

Re: My Honda CBF125 on 150mpg :)
 

Hi Daniel,
Thanks! You low mpg was not one lucky shot. Great.
But looking at the link: does 'maintenance' also include an oil change? Is it normal you changed oil that much in less than one year and so few miles?
My Honda CBF needs an oil change every 12.000 km or every year (what comes firs).
You're spending almost as much money on oil and maintenance as on fuel ;)

Re: My Honda CBF125 on 150mpg :)
 

Those numbers are impressive...

What speed are you doing those MPG. Are you mostly in city? or you do rural road, because you can't go on highway, well here in north america. What is the top speed (well the speed where you can cruise without being at the limit of the 125cc...).

And how is the ride, have you ever ride a scooter? if so could you compare please.

In portugal, you can run this bike almost all year long for cheap, especially in europe where the gas is more expensive, thats great.

Re: My Honda CBF125 on 150mpg :)
 

You're probably right. I actually spend more on maintenance/tax/insurance than on fuel (new tires, clutch plates, battery, water pump, valve shims, fuel filter, drive belt/sprocket, front brake disc/pads (was a mistake by the first workshop - irl the front rim got deformed on the bad roads...) over the last 45000km - and mechanics' wage).
Oil change period is 10000km for F650s.

Maintenance costs were lower for Ciliegia, but she did not need new tires so far.

(And I'm behind my mileage logs, time to update...)

Re: My Honda CBF125 on 150mpg :)
 

Hi there guys, sorry for not keep updated,

I run 90% on city and rural roads, and i can run it on high ways also,

My top speed is around 125km/h, but my best mileage i did with a very calm down driving :)

This motor only takes 1L of oil, and Honda recommends change it every 3000km. Each maintenance on Honda costs near 27€ (36$).

Past 10 000km, the maintenace will be every 4000km i think ;)

I think the next mileage will be a little better than 150mpg, lets see :)

Re: My Honda CBF125 on 150mpg :)
 

Last tank, did 1081.1km with 15.70L of gas, it means 162mpg.

Some tips to improve my mileage?

I shut off engine at every "downhill", 40km/h at flat roads, climbs usually fix a certain speed, like 30, or 35km/h, @ 3300RPM, idling as most as i can..and so on

Re: My Honda CBF125 on 150mpg :)
 

Hi Daniel, Congratulations on your excellent fuel economy, very impressive. How fast is your CBF 125? Can it go 80 mph? Here in the USA a motorcycle must have at 15 bhp to be allowed on the freeways. Its too bad that Homda and the other major motorcycle manufacturers don't sell fuel-injected small displacement bikes like in Europe .

As far as better fuel economy , ride smooth, corner hard, avoid braking, coast when you can and use low RPMs to accelerate and cruise. You could change your chain drive sprockets to reduce RPMs if your bike has enough torque. Keep your tire pressures up. Consider more aerodymanic streamlining like I'm working on. Check out the Craig Vetter website and his work on the Freedom Machine.
All the best , L&S

Re: My Honda CBF125 on 150mpg :)
 

Do you have a modified tank on this bike? Factory data mentions a 10l tank (but even that could give you great range at 162mpg...)

Anyway, I don't think I can advise you wouldn't already know. Pulse&glide, maybe? I often do that, especially when not in top gear, but I don't know if it's of any use with such a small bike, in top gear. It's less useful even on our 250 than on the 650. At (low) highway speeds, at least. But you seem to move in a very different range. It may work, who knows.

Re: My Honda CBF125 on 150mpg :)
 

Nop, its not modified! This tank is 13L, but it has a little neck up, it can reach almost 16L easily. From factory the 13L are well measured, because they say to fill up until reach the "neck" ;)

thanks guys, i will try an other technic: going up hill with more throttle but lower rpm ;)

Re: My Honda CBF125 on 150mpg :)
 

2 liters
first 37km WOT with another passenger
10km with 2 passengers, normal riding

Total: 129.8km

1.54L each 100km - 152.74mpg

I think works fine the more throttle & lowers RPM's, up hill ;)

Re: My Honda CBF125 on 150mpg :)
 

It makes sense, even though I've never seen any BSFC data about motorcycles - but gasoline engines are usually more efficient under load. Therefore I always try to keep rpms as low as possible and load the engine. In lower gears it means P&G for me. Especially downhills.

(Teresa's gearing is quite different, I can't shift into 5th under 70km/h and 4th under ~50. It's a lot of P&G for me in town. She's just too strong not to P&G.)

One little thing you should try: use like 80% throttle instead of WOT, under 100% load BSFC diagrams tend to show worse efficiency again.

Re: My Honda CBF125 on 150mpg :)
 

The first 40km was the top of "screw the consumptions" :D :D :D

The last 80km was the really economical driving :)

What you mean by BSFC?

thanks!

Re: My Honda CBF125 on 150mpg :)
 

BSFC is Brake Specific Fuel Consumption. It's a way to measure engine efficiency (fuel used per energy produced; how efficiently it turns fuel into energy; not the same as vehicle fuel economy but certainly an important part).

Generally, modern car engines make energy most efficiently (low BSFC) when almost fully loaded. Wider throttle and lower RPM reduce pumping and reciprocating loss. I don't know if it applies directly to carbureted motorcycle engines.

You can google for BSFC and read more about it or look at BSFC maps.

Re: My Honda CBF125 on 150mpg :)
 

I don't know about the modern Honda singles, but the 1970's era single cylinder Hondas I've worked on (75cc, 100cc and 125cc) all had a sliding tube that served as the throttle valve in the carb. It was directly operated by the twist grip throttle. Connected to the sliding tube was a tapered metering rod that richened the mix as you moved closer to wide open throttle. The twin cylinder motorcycles that I've owned used a butterfly throttle valve and the metering rod that richened the mix was operated by a vacuum diaphragm- probably based on venturi vacuum (airflow).

My point is that if this bike has the metering rod directly controlled by the throttle position (twist grip throttle), upshfting early and using WOT/low rpm to climb hills may end up using more fuel because the engine is running really rich.

If this bike has a vacuum operated metering rod, then WOT at low rpm will likely be a good strategy.

If you look closely at the carb, you can tell the difference easily. If the throttle cable comes straight out of the top of the carb (opposite the float bowl), it is a tube type throttle valve with integrated metering rod.

Re: My Honda CBF125 on 150mpg :)
 

I think the modern CBF is fuel injected, at least it surely is in Europe (Daniel wrote he lives in Portugal), just like their CBR125 which I had been eyeing with before buying Teresa.

That bike should be pretty similar to the CBF in terms of fuel efficiency. I almost regret that I didn't get one, but given that I rarely ride in town, I probably couldn't get the same average - by far. For lower speeds, and especially 1-up use on shorter distances I'd surely choose a small displacment bike like this.

Re: My Honda CBF125 on 150mpg :)
 

Yes, like alvaro said, this CBF125 is fuel injected, it has a PGM-FI.

Yes, i searched for BSFC, learned something today, but there is nothing about this bike :\

Anyway, with the power courve, is anything good to know about the best RPM to ride?
https://www.motorcycleraceparts.co.uk...5%2009%20-.jpg

Today did 35.55km with 0.5L, it is 1.406 liters for each 100km, or 167MPG :)

Re: My Honda CBF125 on 150mpg :)
 

It's not enough, it doesn't say anything about efficiency at different loads at the same rpm. Some say that the engine is most efficient at the torque peak, but I'm not convinced at all. And they seem to forget about the effect of different loads.

I can see only two things here: it's perfectly futile to ever rev it over ~8k; and that I'd hate that 'arrow full system' that just would make the bike weaker at the reasonable rpm range.

Anyway, how do you measure FE for these short distances? Don't tell me that you go to the fuel station and get half a liter of gas :D

Re: My Honda CBF125 on 150mpg :)
 

I thought that too. I read somewhere that the best economy is at half of the peak torque, in this case would be at 4000RPM.

No, i explain :D When the tank is cimpletely dry, put 0.5l of gas (a little bottle of water), and when she runs out of fuel, its simple to do the math :D :D

Yesteray i went to the gas station: 1.489? for each liter, and ask the little if i could put 1L. She said 'no problem' :thumbup: :thumbup:

Re: My Honda CBF125 on 150mpg :)
 

That's why BSFC diagrams are used: those are nice 2D pictures with rpm and load axes so one can tell in a moment what's the best. It's hasty to say things like 'it's best at (half of) peak torque', because you can't often keep it under load at such an rpm. 'Sub-optimal' rpms often win over 'optimal' rpm depending on the load to keep the same speed. And it's just the engine, not counting aero drag, rolling resistance, and so on.

...so you carry a set of little bottles filled with gasoline? lol :)

Be careful though, I don't think that the fuel pump likes to run dry.

Re: My Honda CBF125 on 150mpg :)
 

Yup, a little bottle of 0.5L of gas in my bag :p

Yes, im now trying to shift in the 2600, 2700RPM range, for a motorcycle is like shift at 1500RPM on a car..but i think its the best range for economy.

Up hills im trying to put 5th gear, and press a little more the thottle, to keep the speed constant

Every down hill above 300 meters, i usually shut off the engine

Im trying a little of pulse and glide also!

There are any more technics i should test?

Re: My Honda CBF125 on 150mpg :)
 

If you pop it into gear before you come to a stop, can you re-start the engine without using the starter? or just use the kick start all the time?

Re: My Honda CBF125 on 150mpg :)
 

No, it has electric start, it starts very easily. Just push the button in a half of a second, and there you go

Re: My Honda CBF125 on 150mpg :)
 

Huh, you're hardcore or the CBF is very special :D
Teresa would be very angry with me if I shifted at 2700. I know it from the sounds she makes :D So I shift at 3200-3500, depending on the gear and the terrain, to arrive to a usable ~2500. Uphills, 2-up, I often shift to 5th at ~3700-3800rpm, to avoid falling below ~3000... otherwise I shift at 3500 to get 2800 in 5th.

...then I do the same: climb the hill in 5th, at a constant 3000-3200rpm (steeper hills really need that 3200) which means 75-80km/h here. On the crest I pulse then glide until I reach 70km/h, then pulse again. Yes, these speeds are not suitable in town, but I usually ride on open roads - my commute mostly involves a hilly and slightly twisty rural 'main' road (Hungarian route 811).

I shut the engine down when I predict the next glide to be longer than 5-600m (there are 2 to 4 of them along my 25km commute depending on the direction and the in-town route). And I use the starter too, it's very hard to smoothly bump start the 650cc single. Your 125cc should be easier.

Re: My Honda CBF125 on 150mpg :)
 

I bump start my Ninja 250 near the end of a downhill coast all the time, saves the wear/tear on the starter/gear, technique is to match the gearing with the speed..

Most of the time in 2nd gear when coasting near 15-20 mph, hardly even feel the bump, above 25 mph I bump start in 3rd gear.

On my Cheap Chinese Scooter, I just flip the engine cut-off button and the engine comes back to life while coasting..

Re: My Honda CBF125 on 150mpg :)
 

But that will cause "wear" in the chain/sprocket/front sprocket, and in the gear box also

Re: My Honda CBF125 on 150mpg :)
 

I've heard several times about 'wearing the starter' - is that something real? It's just an electric motor, a simple and sturdy thing, I'd expect it to drag me through the continent if I had a battery that's strong enough to fuel it.
(Yup, an F650's starter can actually move the bike and the rider, even uphills :D I had to try it when I lost a clutch cable :o)

Re: My Honda CBF125 on 150mpg :)
 

Even so, i think a starter lasts 80, 90, 100 000km, less than that, the battery dies first, and the engine is up in a half of a second

check a little video i did:

https://www.youtube.com/watch?v=PyUJpDsXSoI

Yesterday i went with a friend of mine, and, of course, the mileage is certanily to forget :D went to highway totally at WOT, 8km, the sparkplug went to 200?C. Even so, hope i can do 1.50 on this tank

Re: My Honda CBF125 on 150mpg :)
 

How often do you replace a starter vs chain/sprocket or gear box?

Starter and starting gear are only meant to be used at start, not constantly moving as the wheels/tires.

Personally, I'd consider chain/sprocket & gear box much more durable than starter gear, since much of the acceleration/deceleration is stressing on the drivetrain.

Chain/sprocket are likely to be easier to replace, too.

I have a feeling if you use the electrical power and the starter to move the bike/rider, you will likely wear out your starting gear really quickly.. say within kms.

Re: My Honda CBF125 on 150mpg :)
 

The starting gear you talk is this?
https://articles.dashzracing.com/wp-c...h-Z-Racing.jpg

mine doesnt have that, only have a electric starter.

A chain, rear sprocket and a front sprocket costs 40, 50, 60€, and it lasts 30k 40k km, in normal driving mode. A electric start can be re-assembled, and the cost is near 60, 70, 80€, but lasts more than 80k km

just a thought ;)

Re: My Honda CBF125 on 150mpg :)
 

Starter gear looks like this:

https://upload.ecvv.com/upload/Produc...2617423510.jpg

It is internal to the engine, wear and tear of the starter gear is not visible, only audible when it is worn. Attached to the tip on the spindle of your starter the turns the crank of the engine.

To replace a starter gear usually mean removing the starter from the engine..

If there is no starting gear on the spindle of the starter, like the image below:

https://img.tootoo.com/mytootoo/uploa...2871db2a9e.jpg

You need to replace the whole starter when the teeths are worn.

Re: My Honda CBF125 on 150mpg :)
 

Nice! Even so, the starting gear lasts tons of km if well lubed (hope it was well lubbed in the factory btw), but usually it lasts 100k km.

I have 12k km on mine, lets see how long the starter or battery "lives" :)

Other thing i thought: starting the engine releasing the clutch with a gear on (4th or 5th gear), cause some heavy wear in the clutch also..

Re: My Honda CBF125 on 150mpg :)
 

Hm, that makes sense. I don't really know how strong are those gears. "May" not be designed to drive that much weight :D

On durability of other parts: the first drive belt lasted 63k km for me, rear sprocket wore off at 82k (literally wore off, because the replacement I had ordered from ebay took half a year to arrive... I had to buy another one locally and it was twice as expensive, ~480USD). The starter is ok after 91k.

And I had to replace the battery twice. The first one lasted 5 years, the second lasted 2...

Re: My Honda CBF125 on 150mpg :)
 

Usually, the starter doesn't have to work while coasting downhill.

IMO, clutch would take much more abuse than starting gear, and likely easier to replace.

Re: My Honda CBF125 on 150mpg :)
 

My clutch plates had to be replaced soon after I got Teresa, at 46k km. I don't know anything about the first owner, but I used engine braking very much at the beginning, down to almost zero, with several shifts along the process, and didn't know anything about rev matching. The new plates are almost exactly as 'old' (in distance) as the previous ones, let's see how long they'll survive! I guess this time they'll last longer, despite all the P&G I've been doing since not much after they got replaced.

Re: My Honda CBF125 on 150mpg :)
 

But, as i said, this bike doesnt have starting gear, so, i only have 2 options: electric start or release the clutch on 4th and 5th, and wake up the engine.

One day, im wondering in a project for my bike. Will consist in a belt drive, like this:

https://image.streetchopperweb.com/f/...belt_drive.jpg

Maybe the FE will be better, what you guys think?

Re: My Honda CBF125 on 150mpg :)
 

I don't think so. AFAIK a bit more energy is lost through belts than through chains. Our chain driven bike coasts a bit better at lower speeds (though it can be anything, not just the belt...)