The CB125F 2021-on topic

[dmw1950]

Could be time for a service Pete, a new plug and air filter should bring it back to the higher figures. The new chain should also help improve it.

[JohnS]

Those figures seem to be too good to be true.
The only accurate way,and it’s not even 100%,is to fill the tank full,note the mileage, fill the tank full again when needed to the same level and note the mileage again.Then calculate mpg.

It sounds like pete07bikes has used that method, and achieved the results he posted.

They confirm the experience of other owners, so whatever they seem is irrelevant.

Well I still say they seem to good to be true.Even Hondas claim of 65km/l,40.39 miles/litre,183.37 mpg,is surpassed in 2 of the readings and how many people can even get this level under riding conditions.I’m not knocking the bike,it’s a great machine,but as a retired engine engineer I do like accuracy.

[Godspeed]

Not sure why you’d be doubting the values. I have got up to 168.02 mpg (imperial) on my Honda Innova (carb’d) and I fill to exactly the same point and log every one of my fill ups on an app, so have 95 trips over the past four years.
Anally retentive, probably
(My PCX125 best imperial mpg is 161.08 on 32 trips over 6000 miles)

[Capitano]

Well I still say they seem to good to be true.Even Hondas claim of 65km/l,40.39 miles/litre,183.37 mpg,is surpassed in 2 of the readings and how many people can even get this level under riding conditions.I’m not knocking the bike,it’s a great machine,but as a retired engine engineer I do like accuracy.

Sometimes it just is what it is. I originally doubted my '92 C90 with a Chinese carb was achieving 150mpg on long WOT runs, but subsequent measurements proved it to be true.

I'm inclined to believe the accuracy, myself. Finger in the air estimates don't usually come with figures to two decimal points.

[Bailey80808]

https://www.fuelly.com/motorcycle/honda/cbf125. shows pretty impressive figures, 100-167mpg.
(I think we can safely say the owner of the first 2015 bike showing 18.7mpg figure hasn't got enough fingers to count on......).

And, the majority of those CBF's won't have the magic eSP (electronic submersible pump) technology, so the average will be lower than Pete's figures.

[urbanfireblade]

Hi all.
I can add my 2021 CB125F mpg figures to help prove the accuracy these little bikes can achieve. I always use the brim tank/miles travelled to calculate mpg, Here’s mine.

164mpg - 330 miles - 9.15 litres
160mpg - 295 miles - 8.64 litres
153mpg - 320 miles - 9.52 litres

Obviously you can see the mpg slowly reducing on each fill up, when I got the bike I was riding purely for mpg, then gradually just rode it enjoying the ride! Mines just over 2,900 miles on the clock, lovely little bike!

I run mine on Shell V Power unleaded as I do all my bikes I’ve owned.

I’ve ridden 120 mile ride outs on the CB125F(60 miles each direction), it happily keeps up with the flow of traffic on country roads, 55-58mph generally full whack in most situations, tuck down it’ll creep up to 63mph and beyond, and hold that speed but I like the 50-55mph zone.

After an hour the seat gets a bit uncomfortable, other than that I really can’t fault it!

[JohnS]

I’d totally believe those figures and assume they will get even better as the engine gets more miles on it.Having re-read my post perhaps I should have said some of those figures seem to good to be true,particularly the 196.36 and 207.72.

[Bailey80808]

I thought I was being funny with my bracketed explanations of eSP in my previous posts, but seeing as nobody else did......

Honda's eSP (Enhanced Smart Power) is some pretty impressive tech, though one of the things that I can't find in detail is what they describe as an "offset cylinder", It's my guess that the cylinder is moved in the direction of crank rotation past T.D.C, this would mean in the combustion stroke the piston & connecting rod would be more directly above the big end increasing power & also reducing side loading (friction against the cylinder) of the piston due to a "straighter" connecting rod.
On the compression stroke things would work the opposite way increasing side loading & friction but the losses on compression outway the much greater gains on combustion....
Maybe...

[Bogger]

You're sort of on the right lines ish. But wrong ish.

There are videos on YouTube which give full and proper explanations.

Bogger

[Bailey80808]

You're sort of on the right lines ish. But wrong ish.

There are videos on YouTube which give full and proper explanations.

Bogger

If you could point me to a video in English that'd be appreciated, I didn't think of YouTube...
I'm not the greatest at searching stuff out & "what is Honda's eSP" just got lots of mainly Indian vids...

But, read what I said then watch this animation, I think I guessed correctly, what do I have wrong?
https://m.youtube.com/watch?v=cpwYbW7hCic