Dual Engine Chopper!

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jrellpictures

New Member
Dec 3, 2009
23
0
0
Frederick, MD
Hey everyone,
I don't know if anyones done this here yet, but im currently building a dual engine chopper. I'm using old bike frames and welding them together with my homemade arc welder! I am also planning on making an electric start with an old electric scooter motor. I will probably post some pictures tonight and i'm looking forward to any suggestions. Feel free to ask any question(my description above was kinda brief)

-Thanks :)
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
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Littleton, Colorado
I can't tell from the photo if the fork is made from EMT, electrical conduit, or galvanized pipe. Either one is not really a good choice for a fork. Both will bend too easily. Steel tubing is a better option unless you're a very light guy and plan to ride only on smooth surfaces. The extra weight of two engines, you didn't say where you plan to mount them, a rider and whatever else you plan to carry will be a load on conduit or pipe. I'm not trying to be a wet blanket or a doomsayer, just don't want to see you invest a lot of energy into something that might not hold up and most certainly do not want to see you get hurt. Keep us informed on your build; sounds interesting and ambitious.
Tom
 

jrellpictures

New Member
Dec 3, 2009
23
0
0
Frederick, MD
Ok so heres a diagram i drew up..feel free to ask q's

and thanks for the info and concern 2door...to tell the truth i have absolutely no idea, i think ill go look at home depot for steel pipe. last time i went, all i saw was galvanized and EMT. i found this pipe in my garage. it feels pretty sturdy and doesnt seem to bend easily. the part of the frame that i have built seems pretty strong also. i think it wil be ok....i hope haha
 

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42blue15

New Member
Sep 18, 2008
136
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St Louis metro, USA
Ok so heres a diagram i drew up..feel free to ask q's

and thanks for the info and concern 2door...to tell the truth i have absolutely no idea, i think ill go look at home depot for steel pipe. last time i went, all i saw was galvanized and EMT.
It sounds like you only looked in the electrical section.

Home Depot and Lowe's do carry some better metals, usually near or in the hardware section. Ask somebody where the "weldable sheet metal" is.

The drawback of what they have is that neither the selection or the prices is very good, but it can be helpful. The largest steel tubing is only 3/4", I think. If you need thicker steel pipe, you may be able to use the schedule #40 and #80 black pipe in the plumbing section. This is pretty soft mild steel, but it may be useful.

There is also places like mcmaster-carr and metalsonline. Their selection is much better but the cost of cutting & the cost of shipping makes this a very expensive way to go. You can easily end up paying 3-4X times as much as what the metal really costs this way, so it's worth looking at other options if you have any at all.

---------

Look in your local phone book for "metals suppliers"; most big cities have at least one.
You may have to buy a full length if they won't sell by the foot, but the price per-foot will still be much less than the pre-cut pieces that the hardware stores sell--and the metals suppliers will have a much wider variety of sizes and shapes to choose from. (a full length can be anywhere from 8 to 20 feet; bring a hacksaw and measuring tape so you can cut it up to get it in your car. Some places charge for cutting......)

If you get to a metals supplier, first ask if they have a scrap pile at all. They often have short pieces left over from big customers who ordered pieces cut to length, and they love it when somebody comes in and asks to buy part of their junk pile. These pieces may not be in the exact sizes you wanted, but they may be close enough to work and are usually sold for considerably less than what they'd usually cost if you ordered them specifically. Bring cash and have exact change.

You can also ask at local welding shops where to get "bicycle-frame-size" metals.
Some welding-supply shops will also sell metal themselves, but usually not much useful for building bicycles. Most I've seen only have the BIG beams and plate for trailer-building on-hand, and don't deal in anything but full pieces. They will probably know the nearest places to get smaller stuff in the area, however.
~
 

professor

New Member
Oct 14, 2009
500
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Buffalo ny area
If your fork material is galvanized pipe- it is quite strong, and heavy- much thicker wall than what is found on bikes. However, welding it creates toxic fumes- you MUST weld it so that you don't breathe the fumes (outside in the wind is good). The weak spot in your fork will be where you weld it to those plates ,unless you just slipped them over the existing tubes, then you have especially good strength. I see no problem.
I do question the heat your welder can make. If 1/16 th. rod can burn thru bike frame metal if held in one place for less than 10 seconds- I think it would be OK - hot enough. I say this because there is no practical way to know the amp output of your welder. Do wear gloves and don't weld in a T shirt- the rays will give you a nasty sunburn.
wear glasses as soon as you start to do anything in your work area.

I give you credit. There was a time when I was building stuff out of almost nothing.
 

jrellpictures

New Member
Dec 3, 2009
23
0
0
Frederick, MD
thanks 42blue15, yeah the next place i was going to check was in the hardware section. next time i'll try it. and if that doesn't work, like you said i can check out some suppliers or welding shops because i think there might be one down the road.
 

jrellpictures

New Member
Dec 3, 2009
23
0
0
Frederick, MD
hey professor, yeah on the fork there was some existing pipe/tube or whatever sticking out. i just slipped the new pipe over and it had a snug fit. yeah i played around with the welder for a little while to get a hang of it and it can burn through metal relatively quickly. on the thicker bike frames it was about 3-5 seconds? i don't remember. but i did some test welding on extra pipe and i clamped it down then beat with a hammer. it held beautifully and it looks like the metal is fusing together and not just siting on top like glue. i'm assuming thats how its supposed to be so im happy with it. I also suit up pretty heavily. i wear really thick jeans, a couple layers of not very flammable sweatshirts and i have a welding mask. actually i made one with some stuff i found in my garage. i tested to see how fire proof it was with my jet lighter. it wouldnt catch so i just cut a box out for a pair of welding goggles and hot glued them together. it works great and saved me a ton of money. oh and for my gloves i have thick pair that are leather and i wear some rubber gloves underneath so i dont get electrocuted.

haha thanks for the credit, i love doin this stuff
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
7,272
1,810
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Los Angeles, CA.
You should keep a fire extinguisher handy with that home made welder!!! (seriously!!)
You should ALWAYS have a extinguisher nearby when doing any welding... period! ;)
 

BarelyAWake

New Member
Jul 21, 2009
7,194
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Maine
Regardless of how this build turns out (and I think it'll be sweet), I just wanted to say you get massive points in my book for goin' out on a limb and tryin' and that's no BS

So long as yer careful and it's sounds like yer on top of that - the knowledge gained in this way is priceless, I really respect those that'll construct whatever it is they need outa whatever's on hand. That's the kinda people I want around me in a pinch.

42blue15's advice regarding metal suppliers is dead on the money btw - it's one of the things we do where I work and seriously, it's a **** of a lot cheaper with a far better selection - the scrap bin is a delight to behold ;)

It's so worth finding one in yer area
 

jrellpictures

New Member
Dec 3, 2009
23
0
0
Frederick, MD
Regardless of how this build turns out (and I think it'll be sweet), I just wanted to say you get massive points in my book for goin' out on a limb and tryin' and that's no BS

So long as yer careful and it's sounds like yer on top of that - the knowledge gained in this way is priceless, I really respect those that'll construct whatever it is they need outa whatever's on hand. That's the kinda people I want around me in a pinch.

42blue15's advice regarding metal suppliers is dead on the money btw - it's one of the things we do where I work and seriously, it's a **** of a lot cheaper with a far better selection - the scrap bin is a delight to behold ;)

It's so worth finding one in yer area
Thanks man, i really appreciate everyones support. It really helps me pursue all my ideas.

And i think i might head out to the local metal shop this weekend if the weather holds up, that was some helpful info.
 

jrellpictures

New Member
Dec 3, 2009
23
0
0
Frederick, MD
how are u gonna mount the motors and which ones are u gonna use
i think i'll mount them tomorrow, i'll post some pictures. But i'm using the 2 motorbike engines to be the main power and the electric motor as a starter and to get me moving. this is because the motorbike engines dont have a centrifugal clutch. i could hook one up but i would rather keep em with out it.
 

civlized

New Member
Apr 28, 2009
689
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Alabama
Dude, I am in awe at your ability and creativeness! Really impressive. I am also very interested in your 2 engine build. I have a few questions. What type of engines are you using? If you don't use a clutch, how do intend on sitting idle? How are you going to tie the two motors output together and get them tuned to accelerate together?
 

Alajoyn

New Member
Sep 28, 2009
71
1
0
Portage, MI
J-rell
Congrats on all the heart going into your project.
The metal wholesales/retail sellers also call amounts of metal other than full stock pieces "drops". If you were closer I'd give you all the pipe stock and metal you need.
What's your ideas on sync for the 2 motors? Not like multiple carbs on a single motor that you can sync up. Interesting since I've thought of multiple motor setup myself, but haven't researched the sync issue nor drive setup.
...things that make you go hmmmm.
Have a fun time. We'll be watchin
Alajoyn
Portage MI