How fast will a beach cruiser with 49cc 4 stroke motor go with a 155ib user on it?

Discussion in 'Motorized Bicycle General Discussion' started by athletichunta, Aug 13, 2010.

  1. athletichunta

    athletichunta New Member

    Joined:
    Jul 22, 2010
    Messages:
    114
    Likes Received:
    0
    Thanks so much.
     
  2. athletichunta

    athletichunta New Member

    Joined:
    Jul 22, 2010
    Messages:
    114
    Likes Received:
    0
    Thanks so much.
     
  3. bairdco

    bairdco a guy who makes cool bikes

    Joined:
    Aug 18, 2009
    Messages:
    6,333
    Likes Received:
    19
    Re: How fast will a beach cruiser with 49cc 4 stroke motor go with a 155ib user on it

    if you rode it off a 2000' cliff, you would reach terminal velocity right before you hit the ground, and would be going about 117-125mph when you hit. approximately...:)
     
  4. ferball

    ferball New Member

    Joined:
    Apr 8, 2010
    Messages:
    599
    Likes Received:
    0
    Re: How fast will a beach cruiser with 49cc 4 stroke motor go with a 155ib user on it

    Probably faster than it should....
     
  5. 2door

    2door Moderator
    Staff Member

    Joined:
    Sep 15, 2008
    Messages:
    16,301
    Likes Received:
    25
    Re: How fast will a beach cruiser with 49cc 4 stroke motor go with a 155ib user on it

    He might be right but I was thinking more like mach 1.2...or there abouts :)

    In all serniousness you question is impossible to answer with any degree of accuracy. There are so many variables involved that we can only make educated gusses. The engines, although outwardly appearing identical, often display quite different performance levels. Anyone with more than a couple of engines will tell you that they all run different. I have one that will run circles around my others and the only difference I've found is ignition timing. The magneto rotors (magnets) are sometimes indexed differently on the crankshaft therefore advancing or retarding the spark. Other variables are rear sprocket size, tire diameter and inflation pressure, drive train alignment, Fuel/oil mix, altitude, rider weight and, it might sound funny but his/her width. More frontal area means slower speeds.
    All in all 25 to 30 is a safe guess. Some have reported higher and lower top speeds but the 25/30 range is a good ball park figure.
    Tom
     
  6. The_Aleman

    The_Aleman New Member

    Joined:
    Jul 31, 2008
    Messages:
    2,658
    Likes Received:
    1
    Re: How fast will a beach cruiser with 49cc 4 stroke motor go with a 155ib user on it

    Stock engine with stock 44T gear on a 26x2.125" wheel, probably just under 30MPH. Every 2-stroke with stock gear I've had (all were 66cc) topped out under 30. The 49cc can rev a little higher tho. For every 1 tooth smaller rear gear, you gain about 1mph.

    I ran a 34T on my first motored bicycle which gave it a top speed of ~38mph (could go faster if I wanted to overrev) and a great cruising speed of 28-30. YMMV.
     
  7. Kevlarr

    Kevlarr New Member

    Joined:
    Jul 22, 2009
    Messages:
    1,628
    Likes Received:
    0
    Re: How fast will a beach cruiser with 49cc 4 stroke motor go with a 155ib user on it

    0.03284257545 mach
    440 inch per second
    21.724406048 knots
    402.336 hectometer per hour

    Or my personal favorite,

    67199.8668 furlongs per fortnight
     
  8. athletichunta

    athletichunta New Member

    Joined:
    Jul 22, 2010
    Messages:
    114
    Likes Received:
    0
    Re: How fast will a beach cruiser with 49cc 4 stroke motor go with a 155ib user on it

    huh? how so?. thanks
     
  9. athletichunta

    athletichunta New Member

    Joined:
    Jul 22, 2010
    Messages:
    114
    Likes Received:
    0
    Re: How fast will a beach cruiser with 49cc 4 stroke motor go with a 155ib user on it

    I won't be riding my bike off a cliff lol, but thanks anyway.

    I was underthe impression that 4 strokes can go alot faster than 2 strokes.

    I had a 2 stroke and it went 28 mph with me on it when i was use to be 160.

    I was thinking 37/40mph
     
  10. scotto-

    scotto- Custom 4-Stroke Bike Builder

    Joined:
    Jun 3, 2010
    Messages:
    6,527
    Likes Received:
    5
    Re: How fast will a beach cruiser with 49cc 4 stroke motor go with a 155ib user on it

    Faster than mine, that's for sure....I'm 181 right now. But mine will max at about 34mph with a 44t rear sprocket on flat ground with a (20+ mph) tail wind....on a good day......a very good daylaff

    A lot of it really depends on the throttle position however.....the air pressure in your tires also makes a bit of difference....many factors and not all 49cc 4-stroke engines are created equal, nor are their transmissions. Is it a Honda or a HuaSheng? Or maybe some other manufacturer? What size tires are you running? Straight pipe or muffler? Altitude? A fairing perhaps? Gearing?
     
    #10 scotto-, Aug 14, 2010
    Last edited: Aug 14, 2010
  11. scotto-

    scotto- Custom 4-Stroke Bike Builder

    Joined:
    Jun 3, 2010
    Messages:
    6,527
    Likes Received:
    5
    Re: How fast will a beach cruiser with 49cc 4 stroke motor go with a 155ib user on it

    Read your post above in Motorized Bicycle General Discussion.....no one can tell you the exact answer as there are too many factors involved.....really.

    For all intents and purposes though, 2door Tom's got you pretty well covered, seriously. But then so does everybody else for that matter.....furlong's per fortnight, you gotta love that! Isn't that the best way to measure the speed of ants.....me thinkslafflaff
     
    #11 scotto-, Aug 14, 2010
    Last edited: Aug 14, 2010
  12. 2door

    2door Moderator
    Staff Member

    Joined:
    Sep 15, 2008
    Messages:
    16,301
    Likes Received:
    25
    Re: How fast will a beach cruiser with 49cc 4 stroke motor go with a 155ib user on it

    My eyes aren't what they used to be so I missed the "4 stroke" reference. However it doesn't change my original answer except to ignor my comment about "fuel/oil mix". The other factors remain the same...sorry for the oversight.
    Tom
     
  13. Allen_Wrench

    Allen_Wrench Resident Mad Scientist

    Joined:
    Feb 6, 2010
    Messages:
    2,787
    Likes Received:
    1
    Re: How fast will a beach cruiser with 49cc 4 stroke motor go with a 155ib user on it

    It really, truly, depends who's doing the asking. If a police officer is asking, I say 25 mph (being that this is the fastest speed they are allowed to go in this state). If it is a stranger, I say 25 mph (he might be an off-duty cop). If it is a trusted friend who can keep a secret, I say "I don't really know. The bicycle speedo is as accurate as an educated guess. Hey, you wanna get in your car and pace me? Maybe the speedo in your old Yugo is a little more accurate." Who really can say exactly how fast they go. Even a calibrated police radar gun isn't as accurate as they'd like you to believe. Sure a radar may be more accurate than almost anything, but if you wanna split hairs - even a GPS won't get you right on the money, it'll be really super close though.
     
  14. Dan

    Dan Staff
    Staff Member

    Joined:
    May 25, 2008
    Messages:
    12,474
    Likes Received:
    49
    Re: How fast will a beach cruiser with 49cc 4 stroke motor go with a 155ib user on it

    Kit engine, around 30/35.
     

Share This Page