new weed eater bike project.

mark20

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Sep 26, 2018
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well, let me just say i got a steal on facebook again!
2 ryobi trimmers for 35$
both run great and have a LOT of compression (they feel like my chainsaws lol)
now my plan was to make a "v twin" style bike engine but i quickly realized that would cost me wayy to much in machine work, and it woundnt fit the frame im using.
so im going to be selling one of them, and keeping the other for this project.

now, this can go 2 ways.
1. belt drive
2 friction drive
im considering frame mounted belt drive since it would look cool, and well, i already have a friction drive lol
im going to use a 20" bike rim (about 18" IRL), and a 3/4" pulley (should give me a gear ratio close to 24:1) this is if i can redesign the clutch to make it work for this application (ryoibi uses a stupid floating design, which i will fix by adding a screw support)

ill keep this thing updating! im going to need to get some money and some steel!
 

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5-7HEAVEN

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Did someone mention V-twin???
Before you discard this dream, actually the project might not entail any serious machine work.
I'm in the midst of molding two 47cc engines to form a V-twin lump of ingenuity.
 

mark20

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Did someone mention V-twin???
Before you discard this dream, actually the project might not entail any serious machine work.
I'm in the midst of molding two 47cc engines to form a V-twin lump of ingenuity.
Well, unless its a geared v twin, its going to require some machining.
Now, there's 2 ways to do it.
Either parallel v twin (harley style) or staggered v twin (literally every other bike manufactor)

You could cut and mill the cases flush with each other (to make them staggered) then make a longer crank pin (or weld both crankshafts together)
Or you could cut a hole in the case (if there enough room) and add the second cylinder on there. And
make the crankshaft work (you choice on style)

Theres my idea on making It.
 

5-7HEAVEN

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Actually my V-twin creation is a faux "V", an optical illusion. No machining necessary.
My 2 Tanaka engines are individual powerplants, closely mounted to look like they share the same engine block. If I choose to fabricate a metal "cradle" for the engine bases, from a social distance, it'll look convincing.
Each engine has its own pocket bike tranny, throttle, drive/driven sprockets and chains. Both chains merge at siamesed chainring sprockets and freewheel at the bike's bottom bracket. At that point they share the same 24t chainring sprocket, which links to the rear cassette.
After the plastic shrouds were removed, the identical engines were test fitted onto an inverted "V" motor mounting platform( a 5" x 5" x 5" piece of angle aluminum). Their optimum mounted position was exactly 90 degrees from each other, like many V-twins/V-6's/V-8' engines.
I've had twin engines on a bicycle before. I know that they can operate individually, and don't need to be synchronized.
Something to mull over.
Of course, you'd need to find a suitable frame.
 
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Don_Parsons

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May 6, 2020
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Double whammy weeder engines front and back,,, what hill can't a 2 wheel drive bike not climb.

And you can power up the front tire to burn the furr off a charging Grizzly Bear...

Oh Yha
 

Don_Parsons

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And a person could stagger/ angle off set them too fit into the frame...

Angle/ Tapper/ Line to follow lower fame tube

Yo Yo Yo
 

5-7HEAVEN

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Double whammy weeder engines front and back,,, what hill can't a 2 wheel drive bike not climb.

And you can power up the front tire to burn the furr off a charging Grizzly Bear...

Oh Yha
Yeah!
I've seen twin weed wacker engines on Youtube.
One for each wheel.
Friction drive, gravity clutch.
 

mark20

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Sep 26, 2018
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Ill probably be keeping this bike pretty simple at first, currently looking for a way to mount it using the bottle cage mounts.
If i can find a bike thats not over priced, ( people are gauging prices for bikes right now, i saw a huffy cranbrook for $240!!! A few weeks ago)
Going to be lots of fun!
 
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