Full suspension gas tank frame design concept.

curtisfox

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May 13, 2010
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Wheel goes up will cause chain slack, so you are going to run 2 chains? One to bottom bracket jack shaft? You will also have to offset your motor to clear 3" tire.........Curt
 


Sitherus

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Apr 4, 2016
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Wheel goes up will cause chain slack, so you are going to run 2 chains? One to bottom bracket jack shaft? You will also have to offset your motor to clear 3" tire.........Curt
I dont get it? if I the crank rotates with the whole rear of the bike why would it create slack? how do other bikes do it? they all attach to the crank.
Also again It will be jack shafted. If I want there to be a second chain I will draw it.
 

curtisfox

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May 13, 2010
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If you are going to run 2 chains, with jack shaft in bottom bracket there will be no chain slack? .........Curt
 

curtisfox

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That will work, the closer the pivot to bottom bracket the better, like a mountain bike pivot..........Would also work with your early design, just change the spring angle like this one.........Curt
 

Tony01

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Jun 21, 2016
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View attachment 86124This is the chain path Im thinking. Also as i said earlier but didn't draw it until now, there will be a press in bearing built into the frame so i dont need to buy a kit just the hd freewheel.
Not good sorry. Pivot in the wrong place for a motor build, frame not big enough for a 4-stroke. Spend some dozen hours reading about search terms as anti-squat, chain efficiency, motorcycle cg/ handling dynamics, and predator 212 engine dimensions.

Also that swingarm would fold up on a harden enough impact.
 

Frogslayer

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Jan 20, 2019
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Not good sorry. Pivot in the wrong place for a motor build, frame not big enough for a 4-stroke. Spend some dozen hours reading about search terms as anti-squat, chain efficiency, motorcycle cg/ handling dynamics, and predator 212 engine dimensions.

Also that swingarm would fold up on a harden enough impact.
Don't listen to this guy. Your chain path looks fine. If everybody always built in what is tried and true we would never have anything new. The engine in the drawing is obviously a China girl. How can you know the strength of anything without knowing the thickness of the tubes and the diameters?
 

Sitherus

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Apr 4, 2016
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Don't listen to this guy. Your chain path looks fine. If everybody always built in what is tried and true we would never have anything new. The engine in the drawing is obviously a China girl. How can you know the strength of anything without knowing the thickness of the tubes and the diameters?
Thanks for your support. I havent decided on the frame material yet let alone the rest of the specs. I wonder if carbon fiber would hold up?

Not good sorry. Pivot in the wrong place for a motor build, frame not big enough for a 4-stroke. Spend some dozen hours reading about search terms as anti-squat, chain efficiency, motorcycle cg/ handling dynamics, and predator 212 engine dimensions.

Also that swingarm would fold up on a harden enough impact.
I don't like 4 strokes, I like the looks feel and upgradability of the 2 stroke, however if you want to kill yourself with the extreme power and torque of a 212cc engine, or go to jail for street riding then feel free to remove the seat support bar i only put it there to be able to mount the engine i wanted, and have a place for nos canister, and electrics.

Also if I wanted motorcycle handling I would design this completely different. say a 2 rail frame not one, and a rear tail structure and external gas tank. Thanks for the feedback though, Now i want to draw a motorcycle frame.
 

Tony01

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Jun 21, 2016
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205
I don’t think you guys quite understand the urgency of frame size and safety if you plan on selling them. You may have never intended it but some idiot who puts too much power on it with some questionable mounts can tear it up. People will modify bottom tubes to fit motors so best to take control and make the frame big enough so they don’t have to cut it.
 
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