Home build Tiny mini.

#1
Started on this one kinda shootin from the hip...I picked up two 10 inch wheels from h-Frieght for 6 bucks a piece and I had the Tec 3.5 in storage for such an occasion...Building it for my Great nephew who loves to ride on my mini's when he comes to visit..
I picked up 20 feet of schedule 40 1 inch tube for 20 bucks from my steel guy and bent the lower tube in my hi-tech bending jig in my hydraulic press.

I burned some axle plates out of 3/16 hot rolled steel to start the mock up process...3 inches of ground clearance under tubes and 24-26 inch wheel base are my goals..

I ordered a 35 chain 60 tooth sprocket and plan on using it as a sportor with a caliper cable actuated from a hand lever. I need to make the drive hub once it gets here...
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#2
A little more progress....I bent the top tubes,,They are the same angle as the lower tubes just shorter legs,I gave just enough room to slide the engine out with the spark plug installed..

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This is another view of my "Hi-Tech" bending apparatus..

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Also found a piece of galvy 1 inch pipe and turned the galvy off and sized for a .500 x 1.25 bearing to use for the neck tube..

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Now comes the hard part...attaching the neck tube..
 
#3
I experimented a little with the neck attachment..I cut these tube gussets and think they will work with some more tube length trimming/rake to set trail..I made the fork bridges with 1 inch offset...I have approx 27 inches on wheelbase with the axle all the way back on plates...My plan is to pinch the ends of the tubes closed on the plates after I weld them.

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#4
Today I got the frame welded up..It lined up nicely and stayed true after heat.

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I'm gonna dress up/gusset the neck with either side plates or one down the spine?...Wheel base is right at 29 inches with the offset axle tabs on the front forks,I think it looks better than the wheel on the fork tubes?
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Still not sold on the BMX bars though???I used the bicycle clamps before with good results like on my Finkster Mini.
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Man this thing is tiny! Here is a shot next to my cordless drill for comparison..
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#8
Looking good. Don't trust those harbor freight wheels farther than you can spit. Lol. Tip for the training wheels......If you weld on a foot bar, you can run some sort of a axel through the foot peg bar. Easily removed at a later date.
 
#9
I think the rake needs to be out a little. But that’s just my opinion. I also prefer the wheel in line with the tubes,not so much on the tabs in front of the fork tubes.
i really like the way you Mount the tubes together. Looks like you could easily sell these as weld your own kits. And microbikes are red hot right now.
 
#10
Thanks guys...In case you did not notice I was influenced by the Lil Petrol mini bike with the "crash/pegs" and the straight neck angle...With me sitting on it[6'0] my knee caps are under the hand grips,I figured the straight neck rake would keep the bars out of my belly?..I received the rear sprocket and caliper so that is the next step..Then I can position the motor plate accordingly.
 
#12
Made some progress with the back drive hub...Had to go to plan B because the hub did not come apart like I planned,It was welded to the rim on the long side.I cut some flanges to sandwich the wheel between them and will ad 2 more outboard bearings giving the wheel 4 now.
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I made some 2.5 inch spacers for the sprocket side on the lathe,The flange behind the sprocket has the new 5/8x 1-3/8 bearing.I will cut spacer to go from bearing to bearing also.
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The sprocket bolt hole spacing was the same as the HF wheel believe it or not? I was concerned about the lean angle with the sprocket so far away from tire but looks like it will not be a problem.I did this to get the engine centered better in the frame.
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I am going to have to add a rotor for the brake because of where I put the rear down tubes there is no room for a sprotor system-brake.
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#18
Looks great!
I love when guys build their own stuff in garages.
What kind of plasma cutter are you using?
Thanks for the replies...My table is a Torchmate 4x4 with a cut master Thermal Dynamics with a Machine head torch.

Great detailed pics of the process!
Any chance you might be convinced to share .dxf files for those of us with access to a plasma table? :)
Sure I can share the files...Let me round them up towards the end of the build and I can lump them into one file for you...They're not perfect but will get you damn close,I have the fenders/Engine plate/Kickstand/Clutch/chain cover yet to do....Stay tuned!
 

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