For your comments I present:

Discussion in 'General Questions' started by Gibsonvair, Aug 6, 2009.

  1. Gibsonvair

    Gibsonvair New Member

    Attached Files:

  2. bluegoatwoods

    bluegoatwoods Well-Known Member

    Well, that's interesting isn't it?

    I'm afraid it might break the rules here by having no pedals. But I don't know if that's a real rule and how serious that is.

    Ingenious use of BMX handlebars for foot pegs, by the way.
  3. give me vtec

    give me vtec Active Member

    NICE... I love it!!! ingenious use of materials... where did the engine come from?

    is that a robinson frame?
  4. super dave

    super dave Member

    hey are you trying to trick us wierd but cool
  5. bikeman6969

    bikeman6969 Member

    That is awesome I love it does it go fast? And could we see the other side?
  6. Gibsonvair

    Gibsonvair New Member

    Thank you for the compliments. The first link is a entire photo album. Use the controls on that site to search that album and other albums in my "gallery". The engine is a 25+ year old 2-stroke 85cc Tecumseh with points and magneto.It came from an industrial brush-cutter. Think giant weed whacker! It is rated at 3hp @ 4600 rpm. It goes 29mph on a flat and has been up to 39mph downhill. It is very off-road capable and climbs hills as steep as I dare. Sorry no pedals, but it does ride 2-up (second seat is quick release) and my wife and I have put over 100 miles together on it! The bicycle speedometer is verified and adjusted with GPS. Frame is '80s Huffy chrome BMX style. The Comet torque converter is a clutch and constant variable transmission, 3:1 to 1.12:1. All control is with the throttle. The bottom bracket was converted to a jack-shaft. Drive sprocket is 10 tooth #41 chain and driven sprocket is 48 tooth welded to the inside of the freewheel. It coasts just like a regular bike even with the engine engaged or shut down.
    Steve Gibson
    Last edited: Aug 6, 2009
  7. Gibsonvair

    Gibsonvair New Member

    other side:

    Attached Files:

  8. give me vtec

    give me vtec Active Member

    wow... I am fairly impressed. I like the detachable 2 seat config. didn't see it the first time. Very creative.

    How long did it take you to build?
  9. Gibsonvair

    Gibsonvair New Member

    I don't know how long it took exactly to build this thing. My son came over with a Lawn Boy verticle shaft engine that he had converted to run as a horizontal shaft by rotating the carburetor 90 degrees. He wanted to mount it on this same bicycle. Because the Lawn Boy had starter issues, no cooling shroud and no throttle control, the brush cutter engine was used. This was mid-June. It was completed to it's current torque converter drive by July 3rd. From conception to finish, not more than four weeks. The original torque converter and chain and sprocket came from a Go-kart we had on hand. The brush cutter had engine, hand grips, throttle lever, kill switch and wiring and disconnects that were used with little modification. The thing that was most difficult was adapting the crankshaft to the torque converter. The crankshaft PTO snout was cut off of a 5hp Briggs and Stratton and welded to a 3/4-10 nut. I used a dial indicator to check runout as I welded it on. The engine is on it's second mounting configuration, but 1/8"x1-1/2" steel strap was welded to the bicycle thin wall tubing in both cases. The frame's down tube was clearanced for the engine by sawing a wedge shaped angle from the lower side of the tubing and welding it back together. A 3/8" steel plate connected the verticle gap and provided a place to mount the "foot pegs". The jack-shaft was also pirated from the go-kart, but a 19mm "sealed bearing" kit was used on the bottom bracket and through it runs the 3/4" keyed shaft. The rear seat mount and kick stand came fom an old 1970's JC Penny's 10 speed. It also has an innovative push-pull twist grip shifter that I may adapt for throttle use. The right chain stay had to be clearanced for the new chain position.
    If I can figuire out how, I'll post video. I have a digital video camera, but I don't know how to load it to the computer.
    Steve Gibson
  10. Esteban

    Esteban Active Member

    I " think " I am still trying to figure it out !
  11. SirJakesus

    SirJakesus Guest

    Sweet little bike, I have no doubt that thing can rocket on the off-road trails no problem. Great job!