Gas mileage comparison to cars

Discussion in 'General Questions' started by professor, May 13, 2010.

  1. professor

    professor Active Member

    I am going to use my old Prisim (Toyota) as a comparison point, it gets about 30 mpg around town and weighs 2800# (race weight= includes driver and any junk in the trunk). Why doesn't a 250 pound bike and rider get 300 mpg?

  2. loquin

    loquin Active Member

    bike/rider is less aerodynamic.

    A small bike motor is a less efficient engine. Especially a two-stroke. Older two-stroke designs pump 25% (or more) of the fuel into the air, unburnt.

    An auto uses a transmission to match the engine rpm to the ground speed, so that the engine is running in it's most efficient power band. Most bikes have a single gear ratio, meaning that the acceleration/top end speed are always compromises

    Even with the lower efficiencies, a GEBE with a 25 to 33 cc motor can get over 200 mpg.

  3. professor

    professor Active Member

    Good answer Lou. Had not thought about gearing too.
  4. Mine gets 180mpg, thats pretty good.
  5. motor_head

    motor_head Member

    the smaller the engine the more fuel it uses per hp, and as loquin said 2 strokes release alot of unburned fuel through the exhaust
  6. plinko

    plinko Member

    Where's Gilligan,Skipper,Mary Ann,Ginger,And Mr and Mrs Howell residing now?:grin5:
  7. professor

    professor Active Member

    Saw an article on Mary Ann snagged for Mary Wanna posession.
    My origional thought was the motorbike is about a tenth the weight of an economy car so should get ten times the fuel milage. But they don't.