Jockey Journal Forum banner

New Atom Bomb build...Triumph 750 dirtbike, no I'm not kidding

177K views 623 replies 195 participants last post by  Fred43 
#1 · (Edited)
New Atom Bomb build...Triumph 750 dirtbike, "Carbon Footprint"

After two years, this thing is done. Completed pictures are on page 28 of this thread. VIDEO IS ON PAGE 31, THANK YOU AND GOOD MORNING.

Thanks VERY much to everyone who was into this project for the support and the love.

This may well go down as the single dumbest idea I've ever had, or it may be super awesome. Either way, it's stuck in my head and needs out. I'm making a unit 750 powered full on dirt bike (but with a headlight so I can terrorize the village). Some of you are going to hate this, hell I sort of hate it so far.

First, a few pictures that have inspired me. Note that all of these bikes have tiny little singles in them, not monster ground thumping 750s with huge cams. Many thanks to b50 dot org for having these pictures online so I can look at them and post them here without asking.







So on and so forth, you get the idea. Enough with the inspiration, on with the project.
 
See less See more
3
#2 · (Edited)
So I figured the best way to approach this would be to make the frame and swingarm totally from scratch. Early unit frames are too twinky to take over jumps, and OIF frames are uglier than something really ugly.

As soon as I started measuring stuff (mostly a set of Triumph cases and my 2003 RM250) I noticed that the motor was really too long to put in a dirtbike. So I took the easy way out and sawed the stupid front motor mount off the motor, and started designing my frame to be wide enough to shove the front of the motor up into. What I ended up with is a frame that is two and a half inches shorter through the cradle than an OIF. What difference does that make? Well dammit, it makes a huge difference, because now we can build a really, really long swingarm...for softer landings.

Anyhow. I suck a lot, and all the shit I had to think about when laying out the frame sort of hurt my brain, so these are the earliest pictures I took.



I've got to figure out some kind of front motor mount tomorrow, I imagine that I'll end up with some sort of plates off the case bolts.


Dirt bike or not, I'm still going to waste a bunch of time on stupid stuff like motor mount plates.




There's still final welding to do of course, and I left the rear seat hoop of whatever you want to call it unfinished until I figure out where the rear tire will end up. Once that is done, I'll make the back part of that and slug it on. A few more braces and such will go in once I locate the oil tank, battery, etc.

Oh, as it sits, the frame weighs 9 pounds.
 
#22 ·
I dig. I see the vibe you are going with. I am curious how you are going to support the front of the motor. Curious, not critical.
Me too. I gotta do that this afternoon. I have something simple in mind that will be a great mount...but it might be in the way of the motor going in and out. Make it and try I guess.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top