Bottom End Torque

Discussion in 'Motorized Bicycle Trouble Shooting' started by motortime, Jul 18, 2017.

  1. motortime

    motortime Member

    Joined:
    Dec 26, 2016
    Messages:
    32
    Likes Received:
    0
    66 cc / 80cc chinese engine motorized bike
    26" wheel front and back
    female japan bike
    all parts of the engine are stock

    the above are my specs of my motorized bike. Can someone give an advice on how to higher the bottom end torque of my bike in the cheapest way? the issue here is whenever I pass a hump, I need to gain speed first by pedaling before pulling the throttle or the engine'll die.

    I am eyeing on changing the wheel size and no. of tooth of sprocket in the engine side.
     
  2. mike carter 2

    mike carter 2 Member

    Joined:
    Nov 23, 2011
    Messages:
    250
    Likes Received:
    11
    no need to change wheel size,changeing gear size helps a lot with hill pulling power,you will lose some top end speed though.a larger gear will pull you uphill better,my bike kit came with a 36 tooth gear,i went to a 40 tooth gear so i could get up my drive way.bike went from doing over 40 mph to just under 40
     
  3. Greg58

    Greg58 Well-Known Member

    Joined:
    May 1, 2011
    Messages:
    2,797
    Likes Received:
    41
    Like Mike said changing sprockets will be the easiest unless you have a smaller wheel already, if you don't have a cruiser bike with coaster brake changing to a smaller wheel will eliminate the side pull brakes unless you have a welder to relocate the mounts.
     
  4. Greg58

    Greg58 Well-Known Member

    Joined:
    May 1, 2011
    Messages:
    2,797
    Likes Received:
    41
    Remember brakes are more important than a motor, you don't have to have a motor but have to have brakes.
     
  5. crassius

    crassius Well-Known Member

    Joined:
    Sep 30, 2012
    Messages:
    3,369
    Likes Received:
    35
    yeah, my supplier just got new kits with 36T sprockets - I ordered 20, but passed on those sprockets, so he switched them out for 44T

    real hilly around here such that even the extra power of 40mm stroke and 40mm intake rules out the 36T for heavier riders

    I'm at 150 pounds and one hill behind my house is so steep that it won't allow even a 41T to pull me all the way up.

    I did take a few kits with the 36T tho to offer as options for street racers : )
     
  6. Greg58

    Greg58 Well-Known Member

    Joined:
    May 1, 2011
    Messages:
    2,797
    Likes Received:
    41
    A 44 tooth is a must for a 48cc here. The 48cc needs to turn more rpm to get max power. I tried a 41 tooth on mine and top speed was slower.
     
  7. CRP

    CRP Member

    Joined:
    Jan 7, 2017
    Messages:
    57
    Likes Received:
    5
    Get a four stroke?
     
  8. mike carter 2

    mike carter 2 Member

    Joined:
    Nov 23, 2011
    Messages:
    250
    Likes Received:
    11
    hey crassius,where might i find a 41 or 42 tooth cog,i need the one that has 3 holes.thanks
     
  9. crassius

    crassius Well-Known Member

    Joined:
    Sep 30, 2012
    Messages:
    3,369
    Likes Received:
    35
    never dealt with other than the 9 hole sprockets, so have no supplier for 3 hole
     
  10. motortime

    motortime Member

    Joined:
    Dec 26, 2016
    Messages:
    32
    Likes Received:
    0
    Thanks everyone!
     
  11. Chaz

    Chaz Active Member

    Joined:
    Jun 3, 2012
    Messages:
    909
    Likes Received:
    36
    Mike, I think Custommoteredbikes has them and also MZmiami ebay seller
     
  12. mike carter 2

    mike carter 2 Member

    Joined:
    Nov 23, 2011
    Messages:
    250
    Likes Received:
    11
    thanks every one
     
  13. Tyler6357

    Tyler6357 Member

    Joined:
    Mar 15, 2012
    Messages:
    802
    Likes Received:
    10
    The cheapest way is to get a higher tooth rear sprocket, also, you can get an expansion pipe, as long as you use a long header you will get more low end over stock.
     

Share This Page