Anybody got acceleration numbers?

Discussion in 'General Questions' started by professor, Feb 5, 2011.

  1. professor

    professor Active Member

    How about 0-30?
    I don't have any yet (middle of winter). Anyone else?
    Can't go on and look up motorbike stuff.

  2. jaguar

    jaguar Well-Known Member

    0 to 25 is more fair since around 25 is top speed for those of us without high-rpm engine porting and with stock sprockets. Mine is ported for low rpm grunt but since it has a reed valve, KDX CDI, Dellorto carb, higher compression I'd bet it's not bad at acceleration. I'm just not sure how to test it without a wrist watch. (I've never owned one. by choice)
  3. wheelbender6

    wheelbender6 Well-Known Member

    Like Fred Biletnikoff, mine does the forty in "about a week".
  4. jaguar

    jaguar Well-Known Member

    Another question is about starting from zero. Do we pedal or slip the clutch? Slipping the clutch would probably be most fair since we all have different leg strength. Doing it that way it took me around 10 seconds to get up to 25mph but that was just counting, not using a watch. Another way to do it is start the count from a set mph, maybe 10 or so. That way the skil of slipping the clutch and the leg strength are both discounted.
  5. professor

    professor Active Member

    Yeah, and probably have different catagories like, straight drive or shift kit.
    I don't have a spedometer or decent weather yet.
    "Indecent" weather sounds like a topic for the Combustion Chamber.
  6. Virginian

    Virginian Member

    From 10 mph to 28 mph in 5 seconds - about 200 feet - in a test that I did.

    I have the GEBE system with a Tanaka 32cc engine. To test how fast it could accelerate, I pedaled at 10 mph with the engine in idle (centrifical clutch not engaged). Then I went full throttle and at the same time I pedaled as hard as I could. I checked my speed at 5 seconds. I was going 28 mph and reached that speed within about 200 feet.

    As an old pedal cyclist, that is an incredible acceleration for a bike! I found it thrilling to be able take off like a rocket!
  7. professor

    professor Active Member

    That is impressive. I always liked drag racing. So you added Nitrous footside to your motor.......
  8. Virginian

    Virginian Member

    Nitrous footside - I like that.

    Actually, I can be a pretty strong pedaler, at least for a short time. I've tested it on a bike that measures power output. I can put out over 0.5 horsepower for a brief spurt (maybe half a minute).

    The Tanaka 32 is rated at 1.6 peak brake hp and 1.1 hp continuous. I think the continuous hp is the number that applies to this test. But the motor delivers 1.1 hp only at high revs and high speed. At low revs, like at 10 to 15 mph, the motor delivers only 0.3 to 0.5 hp. Therefore, when accelerating from a low speed, my pedaling more than doubles the power and acceleration initially.

    But after the initial acceleration, the motor totally dominates. I can keep pedaling at 0.5 hp for less than a minute. The motor can deliver 1.1 hp all day long.
  9. jaguar

    jaguar Well-Known Member

    pedaling is cheating. That throws a variable into the equation. We need a test that is standard and doesn't let the strong legs have the advantage. Start your test from 10mph w/o pedaling and report back. Also let us know if you have a shift kit or if its one speed. Two distinct categories.
  10. Virginian

    Virginian Member

    I don't agree that pedaling is cheating. A motorized bike is still a bicycle and I ride it like a bicycle. If I didn't want it to feel like a bicycle, I would get a scooter or a motorcycle.
  11. jaguar

    jaguar Well-Known Member

    I thought the whole point was testing the strength of the engine which would preclude adding any element of leg strength.
  12. professor

    professor Active Member

    Well Jag, we'll just have to add a section for pedal assist.
    Hey! Isn't that what we call these things?

    I think it is fantastic that Virginian can do what he does.
    Also, did you notice his age?
  13. jaguar

    jaguar Well-Known Member

    Yeah i hope I'm still pedaling at that age.
    You know, in motocross it is a race testing both man and machine. So if this "acceleration test" is doing the same then it's not an engine test but a race. Whatever. It don't look like anyone else is interested in testing their machine and posting the results. It would be a great way of seeing what really works at boosting power in these anemic engines.
  14. Wheres my dog

    Wheres my dog Banned

    Even 0 to 25 would nowhere near be accurate...

    Pedaling from a dead stop is required and then this would be biased by how much you pedal or to what speed you pedal

    I would say the only fair numbers would be on dead level ground from say 5 to 25?

    The takeoff from a dead stop could easily vary times by a solid second or so...
  15. professor

    professor Active Member

    Sounds good to me. Doesn't one of the car mags do a rolling start?
  16. 5-7HEAVEN

    5-7HEAVEN Guest

    I'm in!

    I'll do a test as soon as I can run my MB.

    With a Tanaka 47R and a shift kit, acceleration from 5 to 25 should be extremely quick.:jester:

    From a standing start, it would be unbeatable.:whistling:
  17. I should have my bike going with the shift kit in a week or so. I'll come back with results.

    Right now its pretty quick acceleration even with a 36 tooth sprocket on the back.
  18. professor

    professor Active Member

    That is the plan I have too. Except I will need to wait for better weather.
    Just bought a Schwinn bike computer (speedometer).
    I plan to use it as a refrence for calibrating a speedometer off an exercise bike (will paste correct speed numbers onto the dial of the old mechanical meter- the clear face pops off with some careful pulling).
    Also, want to see what rpm the HF turns when wound up.
    So I am going to do the tach trick to the computer. The HF has a magnet on the perimeter of the flywheel, it should be easy to do.