CR200 Chopper Project by cyclhed

I scored a 21" narrow hub front wheel, but the hub is still too wide for the brake rotor to fit.

I'm trying to get my head around how to bend the lower rails and it's giving me headaches! I'm using a single 1.5" down tube and I want it intersect the head tube near the bottom of the head tube. Complicated....I bent up some pieces of wire to try to visualize it. There are 5 bends and 3 rotations in each tube...I think.
 

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Good luck with those lower rails...So Far So Good this clearly isn't your first picnic, Have fun with it
 
Thanks DesmoBro. A friend suggested I bend up some electrical conduit to check it out first which is a great idea. I'm going to go try that now. I'll let you know how it goes.
 
OK time for a little update...

I got the pattern done in 1" EMT for the lower rails and I will try to get them bent up this week. Here are some pics of the set-up.
 

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OK this weekend I got the right lower rail done up to the point at the front of the motor. I need to figure out the bend angle and amount of rotation for this one, so I stopped here and I will practice with some more 1"EMT conduit before I finish bending it.

An easy way to work with this 1.25" OD tubing (if anyone cares) is to divide it into sections and then converting the degrees into length around the tube. Doing it this way you can use a flexible tape measure to mark degrees of rotation on the tube in inches.
The approximate circumference is 4 inches, so 90 degrees is 1", and 10 degrees is 1/8". The numbers are rounded to the nearest fraction, but it works out very well with no error.

Also you need a good way to mark the tubing all the way around. I made a tool to do this from an old BMX bike foot peg that fits snug around the tube. To mark the tube length way use a piece of 1" angle and lay the tube in it and mark with a sharpie.
 

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Oh and I screwed up and made the rear kick up too short so I'll add a 2 inch piece to the end to fix that. It's starting to look like like a motorcycle now (sort of).
 

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I cut out the axle plates and machined the slot with the help of my bro and his Bridgeport. We also cut out the rear motor and front trans mounts and the forward mounts. I also bent up the left side lower tube and it matches the right side nicely. I wanted to put the large 66" radius bend in the front down tube, but the 3' foot length of tube I have was too short to use in my brothers large tube roller. I'll need to pick up a longer piece in order to roll the radius.
 

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I figured out the final bend for the lower tubes. I rotated the tube 0.750" and made a 46* bend in to the center to bring the tubes together at the down tube. I just need to finish cutting the miters. It turned out looking pretty good I think. I'm not sure how I'll finish the bottom of the down tube, maybe just cap it or leave it open.
 

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It's starting to look like a frame. Almost time to start tacking it together. It's a lot of grinding and filing to get it to fit together. It's a fun challenge. If it's straight to within an 1/8" or so you're good after welding it.
 

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Hi folks, I'll get back on this frame soon as I can. I had to stop and install new flooring and stairs in the house to keep mama happy. It's a big project, but I can see the end now. A while back I bought a 88 softail that will eventually be the donor for this bike. I'm going to ride it until I get this rolling and then switch the drivetrain over.
 

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Posting 6 years later. How the chopper turned out. Sold also a couple years ago.
 

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