Performance parts question for a Honda engine.

Discussion in '4-Stroke Engines' started by shawnshank, Feb 24, 2010.

  1. shawnshank

    shawnshank Member

    Are there any performance parts you can buy for the 4 cycle 50cc 2.5 hp Honda GHX50 engine?

    Also, if anyone has one of these on a bike, what's the top speed your getting?
    Last edited: Feb 24, 2010

  2. Old Bob

    Old Bob Member

    Theres nothing out there.
  3. Pablo

    Pablo Motored Bikes Sponsor

    We will slowly add items, but it's not so fun and simple as a HT.
  4. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi shawnshank,

    I have been playing with the Honda & HS motors. I currently have an adjustable main jet setup [Thanks Ron D.], and a intake manifold to mount the larger Whizzer WC-1 carburetor [thanks again Ron D.].

    Last year we worked on several exhaust systems and found the best over all.

    Because the head is part of the cylinder it is next to impossible to do any head work for increased power.

    So far the HS motor has more top end than the Honda, but the Honda has more low end power.

    Top speed [HS motor] on a "Roller Road" is 40 MPH with a stock motor. Top speed on a DYNO was 42 MPH with a stock motor. These tests were conducted using brand X drive systems [not allowed to mention the brand name here], and was much lower with gear drive systems. Best speed with gear drive systems was 35 MPH. These numbers are actual and not guesses or taken from speedometers attached to the bike.

    The speedometer on my prototype has bumped 45 MPH many times, but I am a light rider [165/170 lbs] and tested on level ground.

    Have fun,
    Last edited: Mar 2, 2010
  5. darwin

    darwin Well-Known Member

    Me thinks quentons scale is fibbing to him.
  6. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi darwin,

    You might be right about scales being wrong, and I am sure my speedometer on my prototype is very, very liberal.

    However we managed to add over 6 MPH by tuning the exhaust, adding adjustable main jet, and finding the best drive ratios. The bikes tested we used on the street and all were able to start from a stop without pedal assistance.

    We also discovered why the HS was faster on top end than the Honda. The HS has a much larger main jet, and if the HS carburetor is used on the Honda it will match the HS top end speed.

    I use dynos & Roller Roads [owned by others] to compare the changes, not as an exact science for accurate speeds. It is next to impossible to find two identical dynos, so it makes good sense to test changes on the same test equipment whenever possible.

    By using the same test equipment [owned by others] I was able to set the speed record on a Whizzer @ 68 MPH in 2005. The Whizzer started out at 31 MPH and ended up above 70 MPH on the last test.

    Until now I have resisted doing a little magic to the little 4 stroke, but I can no longer fight off the urge. Looks like I might have my "brand X" 49 CC 4 stroke pulling wheelies and setting new records not to far into the future.

    Here are a few photos of the the record setting Whizzers and the "brand X" [40 MPH] 49 CC 4 stroke.

    Have fun,

    Attached Files:

    stewyou likes this.