Could more CC on the Honda CG = Better MPG???

[Scootaloo]

Hello All

Soon I am potentially about to come into possession of a Brazil model 1989 CG 125cc (Kick start & drum brakes) and a lot of work has been done to it recently and it is currently doing roughly 125MPG - Yay


Now I have been doing a lot of research into good MPG bikes recently, as I'm sick of putting in £10 and only getting a day or two run time from it..

first choice was the C90 but there is a lot of duel lane A roads around my area so I would like something that can cruise at 55-60 (to match traffic) which is a shame as I hear they can pull 150-200 MPG!!

So, after much research I stumbled across the Honda Unicorn (A 150cc CBF) which can do around 140-160 MPG!! and with enough poke to handle 60+ roads... Unfortunately this too impracticable as it's a asia specific model, thus consumables and parts are really hard to find... shame really as it would looking to be the ideal bike for me..

Thus I returned to a bike I was faced with when going for my CBT test back in 2011 - The Honda CG 125cc

Whilst looking on-line I couldn't help but notice there are various 150cc replacements available, here is an example of one: https://www.ebay.co.uk/itm/Cylinder-Big-Bore-62mm-kit-Honda-CG150cc-ATV-Dirt-Bike-/170443817114?pt=Motorcycles_Parts_Accessories&hash=item27af3e409a

I would say I cruse at 40-55 MPH on average..

My question to those experienced mechanics out there is, what would fitting this do for me?

Sweet fuck all would be the typical response I Imagen.. but surely adding 25cc should do something??

Slightly better MPG? Maybe 2 BHP or 3?

Then a more free flowing air filter + removing the rear passenger seat tail and reducing overall weight, should be a considerably different bike. Obviously not much, but anything to make it a bit more urban road capable..

I do love those bike's to be honest.. not sure why.. just find the Cadillac-soft suspension and having to rag every single gear to go anywhere just the most fun ever... even more so than the CBF500... although I will miss being able to race sportier cars around... but that's not a good thing anyway from a licence perspective!

Thanks!
____________________
(CBF125 - 09) (CBF125 - 11) (CB-1 - 89) (CBF500 - 06) (Push Bike) (CB-1 - 90) (XL125 - 01) (VF500 - 83) (GPZ500 - 94) (GPZ500 - 95) (GPZ500 - 87) (XV535 - 94) (XV535 - 94) (GPZ500 - 87)

[P.]

I'm doubting claims of 120mpg from a CG.

[Scootaloo]

[Scootaloo]

Himmmmm

Interesting, the CBF125 seems to average about 120 MPG, 20 mpg up from the CG.. however, the CBF is more expensive than the CG so the real life saving is not there... at the moment.
____________________
(CBF125 - 09) (CBF125 - 11) (CB-1 - 89) (CBF500 - 06) (Push Bike) (CB-1 - 90) (XL125 - 01) (VF500 - 83) (GPZ500 - 94) (GPZ500 - 95) (GPZ500 - 87) (XV535 - 94) (XV535 - 94) (GPZ500 - 87)

[Shinigami]

I wouldn't bother, 100mpg is already high, just spare a thought for us who have to visit the petrol station much more often eg, hornet owners

I get between 42 & 46 mpg
____________________
Current: Honda City Fly CLR125 2003 Honda CB600F Hornet 2008 Yamaha FZ6 S2 + 1991 Kawasaki GPZ500
"Once you realize what a joke everything is, being the Comedian is the only thing that makes sense.

[P.]

[Scootaloo]

[Shinigami]

[Scootaloo]

[Pete.]

If you want better MPG - fit a tall screen.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Teflon-Mike]

From Newtonian defanitions: Power is Rate of Energy Transfer.
Trying to cut a lot of middle order scientific proof to the bone...
The energy in question is your petrol, and MPG the rate you burn it... there-for MPG is an expression of power... 'input'.
The out-put... is getting from A to B.... or 'Work-Done' a force x distance...... except the force your fuel is being used to over come is DRAG... which increases with speed, and more than directly.
Which all means... the faster you go, the more power you need, which means the more fuel you will burn to do the same 'work' getting between two points.

GO SLOW - SAVE FUEL

That is the basic conclusion.

Which means that other than muggering around with any efficiency losses..... doesn't matter whether you have a 50cc engine, or a 1000cc engine..... getting between two points, the fuel consumption is pretty much down to how fast you ride.... not how big the engine is.

And CG thrashed to its limit to keep up with traffic doing 65+ on duel carriageways, is NEVER going to return the best fuel consumption.

Boring it out, tuning it up, rarely makes a thing more efficient and more efficient...... but you have tackled a symptom not a cause....

You want to save fuel on those bits of road..... go slow.

Get in the truck stack in the inside lane and hold the 'efficiency' speed of 55, and let the world such by if they want to burn more fuel to save a few moments!

You'll save fuel, you'll fry less nerves and are a lot less likely to get into a tangle with irrassible impatient BMW drivers.

And costs NOTHING to limit your twist grip travel with a little restraint; needs not be declared to your insurance company, and such restriant is likely to reduce service requirements not increase them... its ALL win.
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

[stuarthouston]

120mpg is impressive, even if it has been rebuilt. Mine just about cracks 90mpg, but that's with a dying clutch, so I daresay it would be more efficient if it was actually transmitting full work done by the engine to the road! I'd like to see it break 100mpg with a new clutch, so we shall see when I replace it next month!

[Scootaloo]

Thanks Tef for the write up.

I understand the general option of just going really, really easy on the throttle... I just can't be trusted really... I don't pin it as such.. but I don't hang around at 125cc acceleration. Going down to a smaller cc is more of a Guarantee of good fuel economy... that 120 MPG figure was found by almost constant pinning everywhere.. so one could be right to assume that I'll get a minimum 100 MPG, no matter how I thrash it.

Same cannot be said for the current ride however.. but I just feel sometimes, it's excessive. never really a need to pin it for anything at all.. thus boredom goes up + more pointless acceleration = worst fuel economy.

So basically what your saying is, If I matched the speed of a CG every single time I drive, I'll return 100 MPG on the 500cc?

I would also like to note, I'm only on the A road's for about 2 minutes.. it's just I HAVE to use them.. so the machine must be capable of 50+ MPH..
____________________
(CBF125 - 09) (CBF125 - 11) (CB-1 - 89) (CBF500 - 06) (Push Bike) (CB-1 - 90) (XL125 - 01) (VF500 - 83) (GPZ500 - 94) (GPZ500 - 95) (GPZ500 - 87) (XV535 - 94) (XV535 - 94) (GPZ500 - 87)

[G]

[Pete.]

You'd have to do a helluva lot of miles at CG consumption-rates to off-set the cost of an LPG conversion.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[G]

Not looked into it, but I'd have thought that once you've got it (and I have looked in to the electric so I know it's the case there if you do it right) that it wouldn't be a massive amount of trouble to move it to the next bike when you came to sell - especially if it was another single for the LPG.
Shouldn't need that much stuff for a basic LPG setup for the CG I'd have thought?

[stevo as b4]

You seem to be wanting to go way out of your way to buy a bike that can achieve 100-125mpg, above all other factors, except that you want to ride at 55mph on big roads.

My CG125 would certainely never do more than around 90-95mpg, and I never needed or wanted it to. They have a 200mile+ tank range which in bike terms is pretty decent. You could as other's have said try to ride efficiently and steadily, and maybe look into wind protection and aerodynamics.

Engine tuning and capacity increases are absolutely not in real terms going to help mpg, and will normally adversely affect it, but never improve it, when your talking about bikes.

I rode a CG and pretty much used it flat out, or at least 75% of it's performance most of the time. I would cruise it at 60mph sometimes, just so that the throttle was not on the stop, which was 3-5mph more at best. I still got 90mpg+ from it all the time, but never broke 100mpg as far as I can remember. I was well impressed enough at that, considering the thrashing it got.

Why do you exactly need or are deliberately seeking out a 125mpg+ vehicle? This aim is going to be at the expense of practicality, usability and safety IMO. If your looking for 150mpg, even a 50cc scooter aint going to help you, and surely you'd be better off cycling or something to save using any fuel at all. That's how daft I see the 150mpg mission and aim that your seeking is.

Bikes like car's need a certain amount of performance to be safe, and anything that can't reach around the speed limit or a bit more for the type of road your using it on, is not really suitable for todays road conditions. Buy a bike because it's something you like, something you want, or need for transport, and live with the running costs or don't bother.

[Cyclingbiker]

My CG BR-J being rather old does about 85mpg and can drop as low as 75mpg if I am running above 55mph for long periods. I'd love to get closer to the claimed 100mpg at 60mph all day but I've never had close. I suspect that the newer models with less miles on would be more capable.

Bear in mind I have recently replaced a leaking fuel hose and stopped the carb from overflowing, replaced a split inlet manifold and bought a new exhaust to replace the old one which was blowing. Before all that was done it wasn't abnormal for me to get 65mpg
____________________
Honda CB500s (1999) - Honda CG 125 BR-J (1991)

Mod 1 - Passed - 12/11/12 --- Mod 2 - Passed - 26/11/12

[27cows]

I had a late 80s one (with '4 stroke' on the panels) and that would do about 110mpg under normal usage. Got about 140 once by coasting down hills and whispering along doing no more than about 45, just to see how much was possible. Mind you, it only had 4000 miles on it when I got it. I would expect the fuel economy to deteriorate over time.

Had an SS50 (one of several bikes I should have kept and bitterly regret parting with). It did about 40mph and 200mpg. It was just completely mental. At that point (somewhere around 1989), 2 star was about 37p a litre.
____________________
The RXS100: vehicle of choice for Chuck Norris

[Sako]

my GSXR 750 is piss poor on mpg, but thats not why i bought it.

just to help you out a little in your quest for better mpg, have you considered buying a bicycle, these can return fantastic savings over petrol powered vehicles by the use of your legs (I apologise in advance if you don't have any legs)

[Teflon-Mike]

[Teflon-Mike]