That depends on your riding style and the two bikes you would be comparing. Myself I ride to commute to works so no lolly gagging as I am on a schedule. With my 150cc carbeurated Lance Vintage I would get 45 to 50 mpg on 40 to 45 moh roads while my fuel injected Sport Cuty 250 gets between 70 and 80 mpg on the same commute.
Not much gain. A properly jetted carburetor would get about the same gas mileage as fuel injected. The biggest advantage would be cold starts. No need for a choke on the fuel injected.
And, on a side note, I've had two fuel injected 250 scooters (Yamaha and Kymco), and neither one ever saw 70 mpg. Perhaps if I only drove 40mph from gas station to gas station without stopping... I consistantly get 55-65mpg.
If you had a choke, you could tune the carb on the fly for the perfect fuel mixture! If your carb is tuned a bit too lean, you could use the choke to cut airflow a bit (richen the mixture) and find the perfect AF mixture (the bike will perform better on the perfect mixture).
The benefit is that your bike will be performing optimally, with best performance and highest MPG.
The cons are if your bike is too lean, you need to cut back too much on airflow with the choke, and if you're having a 250cc engine for instance, and cut back too much on running lean and on the choke, you could be getting only eg: 225cc's of fuel mixture in the cylinder, instead of the full capacity; so you'll get performance loss.
But a correct AF ratio on a bike that's running only slightly lean usually outperforms an incorrect jetted bike (too lean) without choke modification (meaning without cutting back on the air).
It also depends on the final drive gear, and CVT or manual, as well as average driving style (city with start-stop traffic, or country, with long roads at 35-40MPH, or highway with 60+ MPH roads. MPG is optimized when the engine RPM is as low as possible, while the speed is as high as possible. Most of the time, a ~200cc engine running at 1,5k RPM, going 35MPH is having the best MPG you can get out of a bike (even better than a 50cc at 6k RPM).
I think the best overall bikes are the 200cc bikes. Power enough for the interstate (70MPH), and also power enough to pull the ride at 40MPH at the bottom of the RPM range (1500-2000 RPM).
So the answer to your question is not an easy one. But just to give you some kind of an answer: The BMS TBX 260 with Fuel INjection gets 80+MPG. The Suzuki TU250x with FI gets +MPG
Most chinese 250cc carbureted bikes get 65-75+MPG.
Last Edit: Aug 21, 2013 15:49:26 GMT -5 by prodigit
Unfortunately the scooter carbs do not have a CHOKE, they have an ENRICHER they work the OPPOSITE. A CHOKE CUTS OFF AIR so more fuel gets sucked out and ENRICHER by DEFAULT FEEDS EXTRA fuel for cold starting then CUTS OFF THE FUEL. Alleyoop
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