Crazyhorse's How to stretch a StingRay Chopper conversion into a XXL Chopper!

Discussion in 'Stretch Cruiser & Chopper Motorized Bicycles' started by Crazy Horse, Feb 5, 2013.

  1. Crazy Horse

    Crazy Horse Dealer

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    This is how I Stretch / Convert most styles of StingRay Choppers or Clone OCC Chopper into a Schwinn XL Chopper or the Schwinn XXL Chopper style build.

    Here's a Parts & Tools list that you'll need to get started:

    Tools and Equipment:

    For cutting the frame up use a hack saw, reciprocating saw ( Sawzall ), angle grinder, or steel chopsaw for the straightest cut.

    For welding the frame back together, a welding shop or your own personal welder.

    I use 1-3/4" round steel tubing for the top tube, and downtube from headtube.

    I'd suggest sleeving slightly smaller steel tubing inside the 1-3/4" steel tubing for extra strength for the new extended steel tubing that you'll be using on the top tube which runs from the headtube to the rear triangle and the for the new extended tubing which you'll be using on the steel tube which runs from the headtube to the bottom bracket also known to some builders as the pedalcrank.

    I use 1-1/2" X 4" X 16-gauge rectangular steel tubing for the bottom tube.

    You can build this Stretched Chopper as an XL Chopper with a 22" bottom tube, or you can build this Stretched Chopper as an XXL Chopper with a 30" bottom tube.

    Notice: Remember your leg length should determine the amount of Stretch you decide on, 5-7-inches to 6-feet tall you'd want to only add a 22-inch bottom tube. 6-feet or taller go for the XXL Stretch Chopper with bottom tube measurement of 30-inches.


    You also need 2 stock 20-inch StingRay or OCC Style Chopper Bicycles to chop for your build. Or just one if you can source the 1-3/4" round steel tubing.

    I prefer using the 1-1/2" X 4" X 16-Gauge Rectangular Steel Tubing for the bottom tube so that I can easily add a Honda crf50 or Pitbike, and or kids ATV ( 49cc - 125cc ), engine's to the square / Rectangular bottom tube.

    I'll be posting a few how to pictures showing you where I cut my frames, and other pictures as I go through the build.

    Here's what a stock / regular sized 20-inch StingRay Chopper frame with a 14.50-inch bottom tube looks like next to a XXL Chopper with bottom tube measurement of 30-inches . Notice the Xl Chopper Bicycles have a bottom tube measurement of 22.50-inches.


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    Here's what the Round Steel Tubing and Rectangular Steel Tubing I use looks like.

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    This what you'll be aiming for if you go for the 30-inch stretch for a XXL Chopper.

    [​IMG]

    To be continued soon....I have to upload pictures of where I cut the frame, then I can post them.
     
    #1 Crazy Horse, Feb 5, 2013
    Last edited: Feb 9, 2013
  2. Crazy Horse

    Crazy Horse Dealer

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    A few more pic's of where I make cut's to Stretch the frame on the Schwinn StingRay Chopper.

    I put a coat of grey primer on the frame, so that I could write with black magic marker showing the cuts to make.

    On the Top tube I measure from the rear triangle 11-3/4" this measurement keeps the front gusseted portion of the frame intact.

    On the tube from headtube to bottom bracket I measure up from the bottom bracket 6". After this cut the front of front section of frame is now removed.

    The final cuts I make are complete removal of the oval shaped steel bottom tube. I start by cutting around the seat downtube, trying to save as much of the seat downtube as possible.

    Then I cut the bottom tube just in front of the rear triangle, then I cut the remaining portion of the bottom tube off the bottom bracket.

    You are now ready to start mocking up the frame and measuring your new steel tubes to be used for lengthening your frame.

    Pic's

    Here's the primed frame with measurements / marks showing where I make my cuts.

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  3. buba

    buba Member

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    go to it crazy

    thanks for posting

    i have a accumulated a few of the little choppers and strong bmx's with some vague ideas of chop --strretch and end up-0 with something strong and worthwhile engine choices are you going with the lifan's you favor???? or ????

    you inspire and motivate

    thanks buba
     
  4. Crazy Horse

    Crazy Horse Dealer

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    Thanks buba, and yes this build will most likely be motorized with a Honda Mini Trail 50 ( 49cc ) chinese cloned engine.

    Although the Harbor Freight Tools,
    HORIZONTAL ENGINE, GASOLINE, 212CC OHV 7HP PREDATOR ENGINE- Item#69730 this alternative engine will easily fit the Stretched Schwinn StingRay XXL Chopper it's a thought haven't decided which engine I'll use yet.

    Here's what I've accomplished today.

    I start with notching the rectangular steel tubing which I use for the new bottom tube. I notch it so that 1/2" of the rectangular steel tubing it slides under the rear triangle doing this adds strength to the rear triangle. See pic's.

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    Next I'll notch the rectangular steel bottom tube and weld the bottom bracket. Then I'll add new extended 1-3/4" round steel tubing for top tube and new down tube.
     
    #4 Crazy Horse, Feb 7, 2013
    Last edited: Feb 7, 2013
  5. LabRat

    LabRat New Member

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    Will you put pedals back on the frame or will you use an engine with the pedals?
     
  6. Crazy Horse

    Crazy Horse Dealer

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    Gotta have them pedals here in the Washington, D.C. area to get the Moped designation / Registration.

    Or use this Honda crf50 style pitbike engine used on the SSR Laser / Motorino Pedal moped engine, with the built in pedals on the engine.

    See pic's below:

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    Working on my tubing notcher right now Labrat, trying to get a good fishmouth cut to weld up the bottom bracket to the rectangular steel tubing just right.

    I'll post up some pic's soon.

    C.H.
     
  7. Crazy Horse

    Crazy Horse Dealer

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    Well, I thought I'd share some updated pictures of this slow but ongoing build.

    The bicycle frame Jig is a Culvercityclassics and Sportscarpat inspired home shop version.

    1.
    Using Culvercityclassics bicycle frame jig version of C-Channel also known as Uni-Strut, with spring nuts and angles etc...

    2.
    Using Sportscarpats version of an engine stand so I can rotisserie ( rotate the frame ) spin the frame so I don't stress my back into a position not unlike the old 1970's game called twister.

    Thanks to both of you, you are both gentlemen and artist's.

    [​IMG]

    [​IMG]

    See more info parts & pictures here in my Bicycle Frame Jig Album on how to build your own personalized version of this bicycle frame jig.

    Just click on link below to my photobucket album Bicycle Frame Jigs:

    http://s978.beta.photobucket.com/user/ICrazyhorse/library/Bicycle frame jigs?postlogin=true

    I'm also working on a Bicycle Frame Jig, that can be used for one style frame ie / meaning production frames as well as an adjustable Bicycle Frame Jig, this is a work / design in progress.

    Thanks again to Culvercityclassics & Sportscarpat for the inspiration / design / style of frame jig's that they've designed.
    Sportscarpat for his idea of using an engine stand Jig for rotisserie spinning the frame around, and CulverCityClassic's design using the C-Channel / Uni-Strut inexpensive frame jig!

    C.H.
     
    #7 Crazy Horse, Feb 26, 2013
    Last edited: Mar 7, 2013
  8. Crazy Horse

    Crazy Horse Dealer

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    Adult Size Schwinn Stingray Choppers?

    I've heard it rumored that an American Company will in the not to distant future be offering another option of a Stretch Adult Size Chopper bicycle, loosely based on the original Schwinn StingRay OCC Chopper.

    It's rumored to have 4-1/2 inches longer frame, which could easily allow mounting of the cloned pit bike motor originally used on the the Honda SS50 Honda crf50 & Honda Cub's.

    This rumored frame is supposedly going to fit riders 5ft 8inches and taller, and will also have plenty of room for a 2-stroke bicycle engine kit motor.

    If you like this, share your thoughts / opinions etc...
     
  9. d_gizzle

    d_gizzle New Member

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    Did this happen? I'm definetly interested in 20" motorized choppers!
     
  10. SchwinnStingray

    SchwinnStingray New Member

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    How do you guys go with welding the mild steel to the chrome molly frame?
     
  11. maciver02

    maciver02 Member

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    I'd be VERY interested in learning about this new bike, C.H.!
    .shft.
     
  12. Carlos Pinto

    Carlos Pinto New Member

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    Hi Everyone!!!
    I know this is and old thread... but is there any way to put back the pictures that show all the process!!??

    Please!!??
     
  13. NikoTheHa

    NikoTheHa New Member

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    I was thinking the same thing!
     
  14. NikoTheHa

    NikoTheHa New Member

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    I'm curious if you did this stretch with a donor frames tubes. I kinda get the idea on where you put the cut Mark's for the main frame, but the donor frame I dont wanna mess that part up
     
  15. MEASURE TWICE

    MEASURE TWICE Well-Known Member

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    Hope I am not high jacking this thread:

    I was looking at this only as you had created new activity on the thread. I know if you get some used bike parts free or cheap, cutting them up for parts as donor should not be an issue. The cost of metal that is not from a used bike would be costing much more. Getting the tubes to be the right shape and size quite difficult too.

    I did make adjustment to the rear drop outs on my bike when the sheave I was using (washing machine pulley) had to be replaced and I got a Cloned Whizzer part that was not going to fit. It stuck out to the left side more and would scrape the drop out.


    My way to resolve it was to cut just half of only a short 3 inch section of drop out away to make it fit. But prior to that I welded thick steel stock flat metal to the out side. Then another section of the same welded on top. No warping this way if I had to cut completely through, which in this case I did not. It is like a jig custom built that is never removed.

    I intend on making a mountain bike for off road with 6hp HF engine possibly. I think if I wanted it to look nice, then CH's way using similar frame tubes is very good. Though I am looking for cheap and functional, but quite strong.

    For extending frame I have to have a jig and also maybe set up my gantry hoist to set up at a level easy on my back. The bike on the ground is tough. Then mark things up for cutting once it looks right.

    A solid jig to hold the pieces before welding. If possible putting some thing inside the tubes (not only as added strength, but to act as a jig itself that is welded and left in place. A nice donor part that matches the bikes outer tube diameter, and slightly shorter could slip over except at the ends the inner tube. Welding all and polishing you would not notice the inner strengthening tube.

    Use of a straight edge and a level to be sure things are true. Level out a work surface and use it to record angles from that reference before cutting. Then afterwards use the same angles recorded earlier to put the angle back before welding.

    Tack weld, or even as I have done use sheet metal short pieces welded on, just to hold things in place enough and later grind them away when tack and final welds are done. No body will ever know they were there.
     
    #15 MEASURE TWICE, Jun 10, 2018
    Last edited: Jun 10, 2018
    NikoTheHa likes this.
  16. NikoTheHa

    NikoTheHa New Member

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    Definitely some good ideas. When looking at the cut marks CH used, from what I see, those are the exact spots where the tube is perfectly round and easy to splice in a normal piece of 1.75 tube. But when there was mention of using a donor bikes tubes, I cant really imagine how those would work out since they taper off to an oval shape on each end. So I'll probably just do like CH did and use the normal round tube bought, and totally replace our the bottom tube since it's full oval shaped. I have complete bikes to spare, but rather not hack um up if not needed.
     
  17. NikoTheHa

    NikoTheHa New Member

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    Hey Carlos.... I haven't really got any word back from CH but I'm diving into it. My frame is cut up and I ordered tubing which should be here in a few days. I'm going to sleeve the pipe and was originally going to mig it, instead one of our welding instructors at work said he'd show me how to tig. I'm taking photos as I do it and will most likely do a post when theres a bit more progress.
     

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