Sprockets idea about sprocket and boost bottle

Discussion in 'Transmission / Drivetrain' started by chopperboy, Nov 15, 2007.

  1. chopperboy

    chopperboy Guest

    Yes i was wanting to know what kind of speeds i would get with a 70cc if i put a 30t sprocket on a 20 inch wheel like my max out and just cruising speed and how fast i would need to be going to engage the clutch. I live out in the country so i removed my peddles. And also what kind of difference a boost bottle would make with this set up.



    Thanks,

    Chopperboy
     

  2. JosephGarcia

    JosephGarcia Guest

    with that set up you better keep your pedals, you dont wanna be running along side your bike and then hop on and try to start it.
     
  3. I agree with Joseph...probably need the pedals...why did you ditch them?
    Andrew
     
  4. chopperboy

    chopperboy Guest

    Because my bike was a trasher and it had shocks and i took out the middle one and it dropped it and then i welded a support bar what about a 36 t with all the same other info?


    Chopperboy
     
  5. Well, just doing the math, the 36 T on a 20" is the same as a 47 T on a 26" wheel
    (of course rounded to the nearest tooth)....since I have not tried a 47 T I can only approximate by using my speed using a 44T and scaling back.....With the 44t I have
    gone about 28 MPH (might be able to go a little faster but the engine winds out pretty good)....since 47 T yields about 6.4% lower gear ratio, I will scale back the speed by the same percentage and arrive at approximately 26.2 MPH....so with your gearing 36T and
    20" wheel revving the engine fairly high (my bike with the 44 T has a digital tach in it and I thing I was pushing 5700 RPM....I'll have to do a speed / tach test again to see the actual engine speed but I am going from memory now).....26.2 MPH is far from the 40 I think you were hoping for....With the smaller wheel you will definately need a smaller gear if you are hoping to break 30 MPH without making the engine scream....or worse blow?
    I don't think anybody here has had an engie give out due to high RPM's but I could be wrong.
    Andrew
     
  6. chopperboy

    chopperboy Guest

    ok thanks for your help what do you think your start engine speed was with the 44t?



    chopperboy
     
  7. Hi Chopper....I couldn;t say for sure but the next time I ride it I'll try to pay attention to the speedo....I'm guessing at least 10 MPH....but I will try to double check.
    Andrew
     
  8. Mogyver69

    Mogyver69 Guest

    Wow, I can push my bike down the drive way and it fires right up with the choke on. If that doesnt work cheat and buy alittle starter fluid at your local walmart.
     
  9. With the boost bottle you can take off from a dead stop with engine running but that would play havok on your clutch life. Also all you would need to start it would be about 4 or 5 feet of downways incline.
    Speeds would be maybe 20 mph. Maybe more.
     
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