Fuel Mileage with Larger Carbs?

I see a lot of riders going from 14 MM Carbs to 17 to 20 MM Carbs. I see everything about the problems in jetting and performance gains but no mention of the fuel mileage!

Right now, I am getting between 70 to 90 MPG Depending on how late I am for work and where I ride. I have a 2011 Tomos Streetmate R with Airsal 65 cc Kit and Tecnigas Next R Exhaust with Modified Airbox stuffed with a Uni-Filter. Geared 28 front and 24 rear.

Has anyone checked their fuel mileage before and after and what are the results?

Re: Fuel Mileage with Larger Carbs?

Probably Fred /

I run a 19 mm phbg (puch polini, 4pedal, 95#main jet) and get over 60 mpg with great performance Better then a 15mm bing (90 jet) I run @ 45mpg

Now a 21mm phbg with a #102 main jet on the same set up gets me almost half the mileage of the 19mm only like 35-37mpg

A 24mm mikuni gets me about 28-32 mpg

These mileages are mostly from running WOT on long stretches of country road @ 50-60 mph

Re: Fuel Mileage with Larger Carbs?

Vincent Hill /

Ken Roff Wrote:

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> I run a 19 mm phbg (puch polini, 4pedal, 95#main

> jet) and get over 60 mpg with great performance

> Better then a 15mm bing (90 jet) I run @ 45mpg

> Now a 21mm phbg with a #102 main jet on the same

> set up gets me almost half the mileage of the 19mm

> only like 35-37mpg

> A 24mm mikuni gets me about 28-32 mpg

> These mileages are mostly from running WOT on long

> stretches of country road @ 50-60 mph

WOOO!! "This is exactly what I wanted to know but never see anyone talk about" With only having a 0.91 of a gallon for fuel and the 250 Ninja getting between 60 to 65 MPG I did not want to drop to much below 60 MPG even if I cannot park the Ninja on the Side walk :)

I have a 14 MM Carb and was seriously looking at the 17 or 19 PHBG trying to balance the performance and mileage along with avoiding doing a lot of work for very little gain. With just your information I now KNOW I am not going bigger than a 19 MM. I apperciate the 100% answer that covered the questions I was thinking but did not ask!

Re: Fuel Mileage with Larger Carbs?

My old gila setup with a 24 OKO got around 40mpg, or 30 if I was heavy on the throttle

Re: Fuel Mileage with Larger Carbs?

Vincent Hill /

Nick SWOOP Wrote:

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> My old gila setup with a 24 OKO got around 40mpg,

> or 30 if I was heavy on the throttle

I thought getting MPG in the 50's was possible but never imagined getting much worse then that (to be Honest)! If I had a 2 gallon Fuel Tank I would be Ok in the 50's (MPG) but not being able to travel more than 30 to 35 miles before reserve would make riding a lot less enjoyable and seriously limit where I could ride to. (Another reason I need to remove the Oil Tank and install a Secondary Fuel tank) Even if at Max I can only add .5 gallons, at least I can ride the bike 100 miles before needing more fuel.

Re: Fuel Mileage with Larger Carbs?

I run a TM24 with a radiator hose for an intake. Main jet is 180 I think. Gets me between 20-26mpg. I've run out in less than 20miles before though with a full tank, I was doing top speed runs. lol

Re: Fuel Mileage with Larger Carbs?

Vincent Hill /

. (Nick) Wrote:

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> I run a TM24 with a radiator hose for an intake.

> Main jet is 180 I think. Gets me between 20-26mpg.

> I've run out in less than 20miles before though

> with a full tank, I was doing top speed runs. lol

"180" Main?? I only run a 200 Main in a set of 40 MM Carbs on my 1056 CC Road Bike which has 4 cylinders of over 260 CC each! WFO it also gets in the high 20's to low 30's. I am quickly losing my desire for a larger carb. I know that 2 strokes can drink fuel but thought How bad can it be with only 70 CC?? Answer A LOT worse than I imagined. I now know why no one ever post about this now.

Re: Fuel Mileage with Larger Carbs?

well, actually, this has been posted numerous times.

here

and here

more here

and even here

There are probably even more threads than I found in 30 seconds of searching...

Re: Fuel Mileage with Larger Carbs?

Probably Fred /

Right ^^ 2 strokes get horrible mpg with big carbs

My 17 ft boat with a 3cyl 85hp engine got 4 mpg at 22-23 knots (25 mph)but at WOT got less then 2mpg.

Your 250cc Ninja though a 4 stroke would get half the mpg it gets if you went or could go WOT all the time.

I get much better city Mpg or better all round mph if I'm going on 35 mph roads.

Just yesterday "I went around the block" (12 mi) on state route with my hand twisted all down for more then half the trip. When I got back I added almost 1/2 gallon of mix to top off my magnum's tank.

Yikes I can't afford the 3+ gallons of premium and synthetic oil mix a week just to ride a hr a day. I'm gonna have to put 19mm carbs on all my bikes though the Gila bikes love 24mm carbs though.

I like stock 100mpg bikes but where I live after I get out of my development they're kinda dangerous and I really could only go north/northwest

South and east have hi speed roads and several steep hills.

To blast you got to pay I guess.

Re: Fuel Mileage with Larger Carbs?

Vincent Hill /

Nick Schroetter Wrote:

-------------------------------------------------------

> well, actually, this has been posted numerous

> times.

>

> here

>

> and here

>

> more here

>

> and even here

>

> There are probably even more threads than I found

> in 30 seconds of searching...

Seriously!! How do you use the "Search" function here? I typed in "Fuel or Mileage" and it brought up "1" item!! Most search functions I have used would have flooded the return with anything that had the words Fuel Mileage and I got "1" Return. Yes, this will help if I can at least know the "Secret" to using Search Here on Moped Army! (Because I KNEW Someone should have mentioned it somewhere in the past and KNEW someone would think I had not searched! Thank you!

Re: Fuel Mileage with Larger Carbs?

Vincent Hill /

Nick Schroetter Wrote:

-------------------------------------------------------

> well, actually, this has been posted numerous

> times.

>

> here

>

> and here

>

> more here

>

> and even here

>

> There are probably even more threads than I found

> in 30 seconds of searching...

Seriously!! How do you use the "Search" function here? I typed in "Fuel Mileage" and it brought up "1" item!! Most search functions I have used would have flooded the return with anything that had the words Fuel or Mileage and I got "1" Return. Yes, this will help if I can at least know the "Secret" to using Search Here on Moped Army! (Because I KNEW Someone should have mentioned it somewhere in the past and KNEW someone would think I had not searched! Thank you!

Re: Fuel Mileage with Larger Carbs?

not a Baron Asshole /

with an efficient engine setup, you should be getting much better than that guys. I have a vm20 on my kstar and get 75mpg and rip over 60mph ALWAYS!

pete

Re: Fuel Mileage with Larger Carbs?

Vincent Hill /

Ken Roff Wrote:

-------------------------------------------------------

> Right ^^ 2 strokes get horrible mpg with big

> carbs

> My 17 ft boat with a 3cyl 85hp engine got 4 mpg at

> 22-23 knots (25 mph)but at WOT got less then

> 2mpg.

> Your 250cc Ninja though a 4 stroke would get half

> the mpg it gets if you went or could go WOT all

> the time.

> I get much better city Mpg or better all round mph

> if I'm going on 35 mph roads.

> Just yesterday "I went around the block" (12 mi)

> on state route with my hand twisted all down for

> more then half the trip. When I got back I added

> almost 1/2 gallon of mix to top off my magnum's

> tank.

> Yikes I can't afford the 3+ gallons of premium and

> synthetic oil mix a week just to ride a hr a day.

> I'm gonna have to put 19mm carbs on all my bikes

> though the Gila bikes love 24mm carbs though.

> I like stock 100mpg bikes but where I live after I

> get out of my development they're kinda dangerous

> and I really could only go north/northwest

> South and east have hi speed roads and several

> steep hills.

> To blast you got to pay I guess.

Yes, it is the Compromise between what you can live with and what the cost are. I knew I needed about 50 MPH to be safe (Just in Washington DC) because the Max speed is about 45 MPH. Most of the streets are 25 so 35 is needed and the Legal Limit for Mopeds on "Level" Ground. WHen I am on state routes in Virginia by the Pentagon and the SPeed Limit is 45 and the Police will pull you over at 46 MPH I am close to maxed out at 45.

SO I am going to a 22 tooth rear for a 50 MPH Top SPeed and cruise at 40 to 45 and first try the 19 MM Carb. I saw the Weekends Manifold which was a lot of straight tubing cut angled and welded for a good fit but I want a Bent tube like MLM Usually makes for a smooth flow but do not want the carb sticking out the side to avoid the issues when I am in the Rain!

Re: Fuel Mileage with Larger Carbs?

Vincent Hill /

Slow Goer Pete Wrote:

-------------------------------------------------------

> with an efficient engine setup, you should be

> getting much better than that guys. I have a vm20

> on my kstar and get 75mpg and rip over 60mph

> ALWAYS!

>

> pete

I "KNOW" from what you said that your engine is making good power and is well tuned because it is more about Throttle Position than anything else. You statement shows you are able to "Cruise" on part throttle even in the 50 MPH Range AND must live or ride on fairly level ground and not have huge issues with Stop & Go traffic.

Re: Fuel Mileage with Larger Carbs?

Probably Fred /

Vm 20 is not 24mm

I get 60ish mph out of my 19mm phbg

And that is at 50-55 mph

So ya 19mm is good for mph

Re: Fuel Mileage with Larger Carbs?

Vincent Hill /

Ken Roff Wrote:

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> Vm 20 is not 24mm

> I get 60ish mph out of my 19mm phbg

> And that is at 50-55 mph

> So ya 19mm is good for mph

That is what I am seeing! Smaller will not make as Much power and Larger will not get the Mileage. SO in a few weeks I will have the 19 MM and will be doing the Jetting for about a week or so to get it dialed in and then I wll make my own statement! Thanks!

Re: Fuel Mileage with Larger Carbs?

whats it feel like to own a 250ninja? Is it awesome? I bet its awesome!

Re: Fuel Mileage with Larger Carbs?

Vincent Hill /

RingringBANG ! Wrote:

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> whats it feel like to own a 250ninja? Is it

> awesome? I bet its awesome!

It is my wife's Bike! SHe got tired of waiting for me to take her for a ride! :) It is a 2000 with close to Road Race tires and gearing and jetting changes! Higher top speed than the New ones and fairly comfortable and good power for 2 up riding. Nice in town and will pass most Big Harley Davidsons (Hardley Ablesons) on the road. I like it MORE than the ZRX1100 and the ZX12R for in town riding and cost about the same as the Moped I bought and spent to make it rideable in town!

Just cannot park it on the Sidewalk or ride it in the Bike lanes and must have license plates where the Speed Cameras and red light cameras and all get me! :)

Re: Fuel Mileage with Larger Carbs?

Vincent Hill /

Nick, Several of the replies you got where for the same threads but I still want to know how you use the search because it totally frustrates me!

Re: Fuel Mileage with Larger Carbs?

Whoops, I didn't mean to link the same one twice. My bad.

Anyhow, simple phrases work best. For instance, if fuel mileage doesn't net you a response (for one thing, it's redundant. Mileage is typically a measurement of fuel consumption over a set distance, ie. one mile) then you rephrase it. In this case, I searched for "mileage". If you wanted to utilize the word 'fuel', then 'fuel economy' would have been better.

Searching that way brought up these results

Then you can just scan through the thread titles and highlighted words to see what might interest you. If you get too many results, then you can narrow it down by seeing what tends to come up as a result to choose new keywords.

Hope this helps you with the MA search function. Good riding!

Re: Fuel Mileage with Larger Carbs?

Seems to me a Mikuni 16mm would be fine on your Tomos

Re: Fuel Mileage with Larger Carbs?

Vincent Hill /

Nick Schroetter Wrote:

-------------------------------------------------------

> Whoops, I didn't mean to link the same one twice.

> My bad.

>

> Anyhow, simple phrases work best. For instance, if

> fuel mileage doesn't net you a response (for one

> thing, it's redundant. Mileage is typically a

> measurement of fuel consumption over a set

> distance, ie. one mile) then you rephrase it. In

> this case, I searched for "mileage". If you wanted

> to utilize the word 'fuel', then 'fuel economy'

> would have been better.

>

> Searching that way brought up these results

>

> Then you can just scan through the thread titles

> and highlighted words to see what might interest

> you. If you get too many results, then you can

> narrow it down by seeing what tends to come up as

> a result to choose new keywords.

>

> Hope this helps you with the MA search function.

> Good riding!

Totally Appreciated! Thank you I will experiment a little more Next time

Re: Fuel Mileage with Larger Carbs?

Vincent Hill /

Flagrant - Wrote:

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> Seems to me a Mikuni 16mm would be fine on your

> Tomos

That is not a lot bigger?? I am totally familiar with Mikuni's and they are very good Carbs but I am trying to avoid taking "Steps"!! 14, 16, then 18 or 19. I want to retain the Bottom End which a 16 would not hurt, but I also want to make as much power as possible with Reasonable Fuel Mileage. I will look and see what results were obtained with this small increase.

Re: Fuel Mileage with Larger Carbs?

Frank Horrigan /

I had a Tomos a3 with a35 top ported to hell with a vm20 and I was getting about 50-65 mpg.

Re: Fuel Mileage with Larger Carbs?

🇮🇹💦 Of the Loin /

19mm is prob the best balanced carb for power/mpg

on a tomos, or a puch 2 speed, you can run a 16 phbg, 16sha, 15 bing, or a 16 mikuni and you'd blast your tits off all day if you slip the clutch a little bit (5w-20 oil in da gearbox)

i have a 21mm phbg on a stock derbi, and it gets ass shit mileage on my tiny tank. I wanted to use a 19, but I guess the previous owner did a REALLY nice job of boring it out, because its a 21mm now. But the power is grrrrrrrrrrrrrrrrrrrrreat!

variated bikes you can have smaller carbs, or on geared bikes make them slip more, and you can reduce the carb size and still have that takeoff

Re: Fuel Mileage with Larger Carbs?

You are up against the wall wanting both fuel economy and power. This is why dual stage carbs were developed for cars. If you really want to pursue this the most practical route for the mopeder would be to have two carbs progressively activated or seperately activated. One quite small and one large. Better atomization and metering at low/mid rpm in the smaller carb is a big part of it. If you are going single carb consider that a reed inducted engine with good porting can use a smaller carb. I suggested the Mikuni 16mm ^^^ as a compromise for the better atomization of the Mikuni and still make pretty good rpm. I really feel though that dual carbs will give you the most dreamy ride and I think you will see more of this in the future at least among the more wacko of us.

Re: Fuel Mileage with Larger Carbs?

Salsa Salsa /

i get great milage.

i rode 50 miles yesterday on my bike. 28mm carb. i Blasted all of those miles.

Re: Fuel Mileage with Larger Carbs?

Vincent Hill /

(Casserollers) ∴ Μ Λ Ι Ζ Σ ∴ Wrote:

-------------------------------------------------------

> i get great milage.

>

> i rode 50 miles yesterday on my bike. 28mm carb.

> i Blasted all of those miles.

>

> http://2.bp.blogspot.com/-WsHritMxru4/T1PxBd0TPOI/

> AAAAAAAACbg/Ej4lHYcwmHU/s640/moped+puch+maxi+hobbi

> t+honda+pinto+swinger+kromag+jcpenny+rigid+hardtai

> l+hard+tail+case+match+grinding+motion+left+mopeds

> +e50+clutch+brace+polini+dio+intake+reed+reeds+pet

> als-5.jpg

That is a NICE Set up! It looks like I could get away with More "IF" the A55 had a Reed Valve Set up so that any negative pressure would draw fuel and any positive pressure will stay in the case during the Overlap period of the piston closing the ports and the Piston opening the Intake.

I have started searching to see if anyone has put an A35 Kit top end on an A55!! I am still not sure why Tomos went to Piston Port except for Cost!

Re: Fuel Mileage with Larger Carbs?

Vincent Hill /

Flagrant - Wrote:

-------------------------------------------------------

> You are up against the wall wanting both fuel

> economy and power. This is why dual stage carbs

> were developed for cars. If you really want to

> pursue this the most practical route for the

> mopeder would be to have two carbs progressively

> activated or seperately activated. One quite

> small and one large. Better atomization and

> metering at low/mid rpm in the smaller carb is a

> big part of it. If you are going single carb

> consider that a reed inducted engine with good

> porting can use a smaller carb. I suggested the

> Mikuni 16mm ^^^ as a compromise for the better

> atomization of the Mikuni and still make pretty

> good rpm. I really feel though that dual carbs

> will give you the most dreamy ride and I think you

> will see more of this in the future at least among

> the more wacko of us.

Now this is something I had not heard or seen. I will do a little searching on this. I know the usual question is how would you cable this? Now that you bring this up, I can imagine someone having 2 - 10 MM Carbs with a Motorcycle dual throttle cable with one having an excessive amount of play so that up to 1/2 throttle you have 1 carb open and after 50% (Could also start at 25% or any other perfentage)Thottle the second carb would start to open so at WOT you have 20 MM of Venturi! Thanks for stirring the idea!

Re: Fuel Mileage with Larger Carbs?

Regardless of the lack of reeds the A55 cylinders are better in many ways.

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