Jackshaft jackshaft

Discussion in 'Transmission / Drivetrain' started by williamsk1936@yahoo.com, Dec 20, 2016.

  1. [​IMG] jackshaft
    As a device to go to sleep I have lately been building motorbike components in my mind. Last night I was thinking of a better way to mount a jackshaft. I would machine the ends of black pipe to accept sealed 16mm I.D. ball bearings. Then mill a portion of the O.D. to receive a flat plate of about 3/16" thickness with rounded corners wide enough to mount U-bolts to secure it to the seatpost above and below the tube. Then a dog-point setscrew or 2 into the frame to prevent the jackshaft unit rotating. Insetting the plate into the tube wall would look better and allow a nicer weld bead. I am still playing with the Lawnboy 4 HP in a Cranbrook frame idea. It might get my COMET VST. Just too cold to do squat right now.[​IMG]

  2. Frankenstein

    Frankenstein Well-Known Member

    Have pictures of bike frame and motor sitting in frame and size clearance? I think I follow the idea what you want to do and sounds like a good idea. I don't know what you mean by milling the tube, to take bearings?

    How will you get the gearwork attached?
  3. I mean to remove pipe wall metal the thickness of the mounting plate so it sits flush and the reduced angle between the pipe and flange will be easier to run a weld bead on and look much better and be stronger. An end mill to be used
  4. Frankenstein

    Frankenstein Well-Known Member

    I'd think just the pipe and 2 u bolts with a single flat plate on the other side of the post might be better looking and functioning. Do about 6-8 spot welds in the right place and it won't move, and will be easier to paint or hide, while also being useful.
  5. Frankenstein

    Frankenstein Well-Known Member

  6. Doing it my way will not alter the frame in any way other than 2 holes for dog-point set screws to prevent rotation and the unit would be aesthetically pleasing (to me)
  7. Frankenstein

    Frankenstein Well-Known Member

    What bar are you putting through the middle?
  8. Timbone

    Timbone Active Member

    I am doing something similar: my plan is to jackshaft my drive chain farther left for clearance to use a motorcycle tire. Same deal. I think your double u-bolt plan with welds is good.

    I am gonna try some thing else.

    My axle will be held in a 1 1/2" steel tube. I will use a strip of thick mild steel that I will heat and bend to wrap around the seat tube. I'll make a template out of thin cardboard so that I will know exactly where to drill the holes. I will leave a little gap between the seat tube and the axle tube and tighten it with a 5/16" or 3/8" bolt. May not even need to weld it.

    I hope you will put pics up of your engineering! Thanks and good luck!
    Last edited: Dec 22, 2016
  9. skyash

    skyash Active Member

    So from what I see you are making this ???

    Attached Files:

    Steve Best likes this.
  10. Frankenstein

    Frankenstein Well-Known Member

    Hey, very cool! And slick too, best part is everything's at lows except for the bearings, maybe..

    What did you machine the tube out to?

    Are you aware there are that same exact bearing, but with a large retaining ring in the wall, which makes things a real snap and benefit of larger heavier gauge tube for longer stand of time. Let's you get creative with panels too, like how sick bike parts pulled it off. Look at photo below...

    The bearing in my hand is the same size and make as the type that get used as a main bearing, except these obviously have rings.
  11. skyash

    skyash Active Member

    I made a hole jack shaft kit from scratch but the gear box on my motor was to over geared .so my gears whent from hard to harder then super hard . Would work on a 66cc I think