Custom Frame For Thumper Motor

Discussion in 'Motorized Bicycle Welding, Fabrication and Paintin' started by culvercityclassic, Apr 8, 2011.

  1. scotto-

    scotto- Custom 4-Stroke Bike Builder

    Joined:
    Jun 3, 2010
    Messages:
    6,530
    Likes Received:
    6
    That's a great looking design Pat, the split sprocket is o so handy! I Jeff can't break, I may be able to.......is that about 60t? The MM adapter I got at Willow won't stay put so it's off of the race bike, I've got something stronger that won't fail come race time. New wheelset done this weekend, think Atomlab, Surly w/ whimpy, stretchy WTB 12G SS spokes.

    Is that hub goin on the 160 or the 200? If it goes on your big race bike and that's a 60t or thereabouts, it should make your gearing just about right!

    Keep up the great work Pat, we need it!

    dnut

     
  2. sportscarpat

    sportscarpat Bonneville Bomber the Salt Flat record breaker

    Joined:
    Jun 25, 2009
    Messages:
    1,751
    Likes Received:
    65
    Thanks guys. I have plenty of hubs available. I burned through the sprocket kits pretty quick but more are coming. As for tooth count I can supply as small as a 40t with this design and as large as a 26" wheel can swing before the sprocket hits the ground!
     
  3. Mr.B.

    Mr.B. Well-Known Member

    Joined:
    Oct 21, 2008
    Messages:
    1,207
    Likes Received:
    37
    You discussed a 56 teeth rear spocket before, I’m curious how many teeth are on the CVT side?

    And with those big gears do you even ever need to pedal...?

    -Kirk
     
  4. scotto-

    scotto- Custom 4-Stroke Bike Builder

    Joined:
    Jun 3, 2010
    Messages:
    6,530
    Likes Received:
    6
    It's a 10T coming off the CVT.....and no, the pedals are pretty much just for looks....you don't pedal these giants.

    dnut

     
  5. Mr.B.

    Mr.B. Well-Known Member

    Joined:
    Oct 21, 2008
    Messages:
    1,207
    Likes Received:
    37
    Hope to not go to far OT here, but I’ve been picking up components for my own Thumper built- I have the Greyhound 6.5hp and Comet Torq-o-verter with a 10t gear.

    I’m not building a racer and plan to pretty much use the engine stock with a Mikuni carb. If fact I’m more interested in being able to climb the hills in my neighborhood, but still have a reasonable top end for the flats.

    For this what would the experienced recommend for the rear sprocket?

    Thanks!,

    -Kirk
     
  6. culvercityclassic

    culvercityclassic Well-Known Member

    Joined:
    Sep 27, 2009
    Messages:
    3,089
    Likes Received:
    59
    Mr. B I like a 50 tooth, you will "B" really happy with the performance.
     
  7. Mr.B.

    Mr.B. Well-Known Member

    Joined:
    Oct 21, 2008
    Messages:
    1,207
    Likes Received:
    37
    I "C"cc

    Thanks Man!

    -Kirk
     
  8. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

    Joined:
    Mar 20, 2008
    Messages:
    6,215
    Likes Received:
    25
    I got to test ride that monster last weekend on the Venice ride... The pedals are only for helping to do easy wheelies!! ;)
     
  9. bairdco

    bairdco a guy who makes cool bikes

    Joined:
    Aug 18, 2009
    Messages:
    6,396
    Likes Received:
    49
    jeff, you and pat should incorporate your chain tensioner and his split sprockets, and you guys would have a winning combo for quick gear changes.

    thats an awesome product. i just wish they were somehow available with smaller sprockets. anything over a 32 and i'm winding out.

    i could always put a 40 on with one of my motors and build a bike that'll do donuts and burnouts...:)
     
  10. Goat Herder

    Goat Herder Gutter Rider

    Joined:
    Apr 28, 2008
    Messages:
    6,251
    Likes Received:
    3
    With your 24 inch tires I say it sure would..boogy1a
     
  11. sportscarpat

    sportscarpat Bonneville Bomber the Salt Flat record breaker

    Joined:
    Jun 25, 2009
    Messages:
    1,751
    Likes Received:
    65
    Hey Baird,
    If you can't get the right sprocket for the engine, then get the right engine for the sprocket. I see a clone in your future.
     
  12. culvercityclassic

    culvercityclassic Well-Known Member

    Joined:
    Sep 27, 2009
    Messages:
    3,089
    Likes Received:
    59
    Hey Pat don't send hi in that direction yet... We need some fame for a bit...lol. I am sure he will cross the line in due time....
     
  13. scotto-

    scotto- Custom 4-Stroke Bike Builder

    Joined:
    Jun 3, 2010
    Messages:
    6,530
    Likes Received:
    6
    Was gonna go with 24" wheels on my current race bike but I felt like it may be like cheating :D


    Hey MB, I've been running a 52T on mine and it's been perfect with my CVT and j-shaft set-up......front end comes up reeeal ez .wee.

    I may run a 56T at Grange, it will be like riding a unicycle laff

    dnut
     
  14. bairdco

    bairdco a guy who makes cool bikes

    Joined:
    Aug 18, 2009
    Messages:
    6,396
    Likes Received:
    49
    i have a goal with these two strokes. i've got a 50cc on the way, which i plan on beating on it to the point where i can challenge the land speed record at bonneville. i've studied it, mapped it out, and set my mind to it, and next year, if everything falls into place, it's me, a crappy chinese stump puller engine on a 1940's bicycle, beating the current class record of 80 something miles an hour.

    confidence-wise, i think i can pull it off. reality-wise, i can get close enough that there's nothing else i coulda done to beat it.

    while you guys are making fragile bicycles to hold giant paint sprayers, i'm trying to make a lawn edger into a rocket booster.
     
  15. silverbear

    silverbear The Boy Who Never Grew Up

    Joined:
    Jul 9, 2009
    Messages:
    8,191
    Likes Received:
    12
    And we old guys are just trying not to fall off our bikes as we watch you go by.

    Pat, that's a great design with the sprocket. Why not a smaller sprocket? My Sachs engine calls for a 28T. It would be nice to be able to change the gearing depending on where I am... mountains or flatland. What is the hub you're using? Nice to have the combination available. Also would be nice to have an easy source for 12 and 11 gauge spokes in lengths for either a 24 or 26 rim. Just wishing...
    SB
     
  16. sportscarpat

    sportscarpat Bonneville Bomber the Salt Flat record breaker

    Joined:
    Jun 25, 2009
    Messages:
    1,751
    Likes Received:
    65
    Hey SB,
    On my drum hub I used the adapter plate thickness to establish the correct offset with a flat sprocket. From there we needed to come up with a sprocket bolt pattern. This pattern was chosen based on available sprocket blanks, which are common and therefore cheaper in current standard sizes. The sprocket bolt pattern has a specific call out number so you can easily order from various suppliers. Give them the tooth count and pattern number with chain size and you can get the sprocket made. Same split pattern as Jr. dragsters and Karts. I can go smaller than 40t, and may, but it will not be a split design.
    Spokes? There are spoke companies that can easily make any spoke diameter and length you need including 11ga for 24" wheels.
     
    #196 sportscarpat, Sep 17, 2011
    Last edited: Sep 17, 2011
  17. dmb

    dmb Active Member

    Joined:
    Dec 4, 2010
    Messages:
    1,359
    Likes Received:
    0
    hey CCC a ''snuff or not'' from the 60's honda 305 scrambler would be nice on the end of that exhaust pipe and you could set it on quiet to sneek around like i used to back then.
     
  18. culvercityclassic

    culvercityclassic Well-Known Member

    Joined:
    Sep 27, 2009
    Messages:
    3,089
    Likes Received:
    59
    DMB whats that exhaust...show me
     
  19. scotto-

    scotto- Custom 4-Stroke Bike Builder

    Joined:
    Jun 3, 2010
    Messages:
    6,530
    Likes Received:
    6
    I remember those things.....it's like a butterfly valve ( washer with a hole in it ) that was a tail piece for the exhaust. That is still a pretty funny joke as I see it......they worked so well, I forgot about them laff

    dnut

     
  20. culvercityclassic

    culvercityclassic Well-Known Member

    Joined:
    Sep 27, 2009
    Messages:
    3,089
    Likes Received:
    59
    I have been riding this bike around a lot lately and felt the pull starter pulley needed a new design. This is the prototype till I get the billet machined one made. It is really not bad with rope starting it.
     

    Attached Files:

Share This Page