bigger engine?

Discussion in 'Frame Mounted Engines' started by senorpyz, May 16, 2009.

  1. senorpyz

    senorpyz New Member

    i am looking at buying bikeberry's 80cc kit, but i am wondering if there are bigger engines that you could swap out?

  2. bluegoatwoods

    bluegoatwoods Well-Known Member

    None that I know of. But I wouldn't worry; 50 cc itself is more powerful than you think. 80 cc ought to have all the "uummph" you need.
  3. cpuaid

    cpuaid Member

    66CC/80CC with a smaller sprocket and an expansion pipe ought to satisfy your need for speed on a shoestring budget.
  4. senorpyz

    senorpyz New Member

    where would i find these parts?
  5. cpuaid

    cpuaid Member

    Last edited: May 16, 2009
  6. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    There is NO 80 cc Chinese 2 stroke kit, no one makes one.....
    Their engine is about 66cc just like everyone elses

    The Grubee 50 cc Gen II motor is smoother and revs out more on the top end.
    The 66 cc Grubee is torquier and has more bottom end especially with a heavier rider or hills
    They are strong motors right out of the box......much faster than a Raw/ PK

    loquin: edited to remove sales pitch
    Last edited by a moderator: May 18, 2009
  7. senorpyz

    senorpyz New Member

    will the sprocket just increase top speed and decrease torque?
  8. cpuaid

    cpuaid Member

    i have the 36T installed on a 49CC slant head which has more torque than the standard engine. slightly slower on the take-off than my 66CC but i can cruise at higher speeds with less engine strain. i have the new jet black 66CC slant head on order and will try it out with a 26T sprocket. with this setup up i should be able to cruise close to the 40 MPH barrier.
  9. senorpyz

    senorpyz New Member

    well i am 130-135 lbs and i am looking to buy a 66cc, how fast do you think i could get going? if you could post a good kit and sprocket combo, it would be very much appreciated, thanks =]
  10. cpuaid

    cpuaid Member

    i'll PM you what a cheap high performance setup would be. The 66CC jet black slant head is sold out. mine should arrive next weekend so i'll keep you posted.
  11. cpuaid

    cpuaid Member

    hey forbisher... great looking 35T sprocket. PM me what they are going for.
  12. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    26" wheels

    26 tooth sprocket at 5500 RPM = 39.9 MPH
    26 tooth sprocket at 6500 RPM = 47.2 MPH
    26 tooth sprocket at 7300 RPM = 53 MPH (True redline on a stock 66 cc)

    26 tooth is geared way too high for an unmodified engine
    and stopping and starting
    you would be doing a lot of pedaling to get going and would be kinda sluggish

    The 66 cc does not have enough HP to pull this high ratio Drive ratio: 10.66:1
    I went with 35 teeth as a good compromise and the Grubee 66 cc is pretty strong

    35 tooth sprocket at 5000 RPM = 27 MPH
    35 tooth sprocket at 5500 RPM = 29.6 MPH
    35 tooth sprocket at 6500 RPM = 35 MPH
    35 tooth sprocket at 7300 RPM = 39.3 MPH (True redline on a stock 66 cc)

    Drive ratio: 14.35:1

    Last edited: May 16, 2009
  13. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    Sorry, I only have enough to supply my local customers and they will go fast....:grin5: in more ways than one.

    Will have more in a week or so and I have to decide on the final design

    The middle is bored out to 1 11/16" about 1/4" more than
    the standard which is about 1 3/8"

    1 11/16" is the same as the rubber ring on the Grubee small 9 hole design