Engine Base & Down-Tube Fabrication

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HybridBiker
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Joined: Wed Nov 16, 2011 10:02 pm
SELF INTRODUCTION: I'm a bit of a tree-hugging biker who thinks 50 mpg from my current bike sucks big time. I want 200+ mpg, and I'm determined to get it! So I'm building a diesel-electric hybrid. Electric will be a 10 KW rear hub motor, diesel will be 19 hp twin and I am going to try it with no transmission to start with.....

Engine Base & Down-Tube Fabrication

Post by HybridBiker »

It's been a while since I last posted. I'm building a diesel-electric hybrid motorbike. I'm currently fabricating the frame. I am using a Honda Rebel 250 rear swingarm and a small segment of the Rebel frame where the swingarm pivots. I have aligned and tack-welded the backbone and steering tube in place.

Next to fabricate are the two downtubes (grey vertical pieces in the picture link below) and the two bottom rails (also grey in the picture). My question is this: What is the best way to fabricate these - one piece or two? Perhaps it comes down to how accurately can one bend tube. I will be taking my tube pieces to someone who can bend it (what kind of place/business will usually do bending?). Can they make the two bends in the bottom rails - i.e. the 90 degree bend between the downtubes and the bottom rails and the 45 degree bend at the rear of the bottom rails - accurate enough to do each rail in one piece of tube? Or would it be best to make a joint somewhere along the bottom rail to allow some adjustment for getting both rails exactly the same lenghts/positions?

:banana-gotpics:
http://s275.photobucket.com/albums/jj31 ... 030002.jpg

Does my question make sense? I hope I am clear what I am asking! :confusion-shrug:

Thanks for any thoughts!!! :character-tweety:
HybridBiker
NewB
Posts: 5
Joined: Wed Nov 16, 2011 10:02 pm
SELF INTRODUCTION: I'm a bit of a tree-hugging biker who thinks 50 mpg from my current bike sucks big time. I want 200+ mpg, and I'm determined to get it! So I'm building a diesel-electric hybrid. Electric will be a 10 KW rear hub motor, diesel will be 19 hp twin and I am going to try it with no transmission to start with.....

Re: Engine Base & Down-Tube Fabrication

Post by HybridBiker »

Oops - just re-read my post. I should have used the term "Bottom Rail" in the subject line rather than engine base..... :angry-banghead:
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gww25
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Re: Engine Base & Down-Tube Fabrication

Post by gww25 »

Any good bike fab shop should be able to make these tubes in one piece. Just take them your mock-up tubes and maybe a few dimensional sketches of what you need. Those are really easy bends to make so the cost should not be to bad.
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railroad bob
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Re: Engine Base & Down-Tube Fabrication

Post by railroad bob »

I typed out a long answer while Gary gave you what you needed in a few sentences...
Alaska - Land of the Individual and Other Endangered Species
An Armed Society is a Polite Society,...
Politicians Prefer Unarmed Peasants
TANSTAAFL
riceburner
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Re: Engine Base & Down-Tube Fabrication

Post by riceburner »

Wear shoes when working around steel.
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