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What mechanical engineers do in their free time

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As a studying Mechanical Engineer, any other Engineers will know that it is quite a hard practice and there isn't much free time, especially if you work outside of school. My roommate and I are always coming up with and doing projects when we have time. Over the course of a few weekends at the machine shop on campus, we took the time and modified an electric scooter we bought off of eBay.

 

Scooter - $50

Engine - $70

Clutch, carburetor rebuild kit, drive sprocket - $60

Misc hardware, frame materials - $40

Chain and throttle/brake linkages - $15

Disk brake/caliper from mountain bike - $30

 

The scooter uses a 5hp Briggs and Stratton engine, unmodified with the governor still in place paired with a go-kart clutch and #35 chain. The governor limits the engine from revving past 3600-4000RPM, which using the size of the tire and these relationships, we calculated the top speed with this gear ratio around 40mph, guessing on the high end of the rev-limiter. With the 12tooth clutch and the 40tooth drive gear, we have reached speeds of 39mph with me on it, (tracked by a following car) - so the it is doing exactly what we originally designed it to do! For around $250 this was a fun little project, and is great to ride around campus - especially from the parking lots in the morning which feel like they are a mile away.

 

I wish I knew more about road legality (I know that it is CERTAINLY not street legal now), but if anyone knows specific laws governing street legality (turn signals, head lights, etc), feel free to suggest anything :)

 

Extended frame

post-5662-12845649911535_thumb.jpg

 

Grinding some paint off to weld kill switch bracket

post-5662-12845650860001_thumb.jpg

 

Mmmm...mig

post-5662-12845651160011_thumb.jpg

 

Grinding some paint off of the frame for welding some support/stiffening

post-5662-12845651329558_thumb.jpg

 

Finished :)

post-5662-12845652316063_thumb.jpg

 

And now for videos (visit youtube page for 720p):

http://www.youtube.com/watch?v=Lm16mO4VcOk

 

and

http://www.youtube.com/watch?v=x9DZVWrDKXk

 

Comment!

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nicely done :)

 

According to Wikipedia SC doesn't require a safety inspection (which is a bit silly) but means that provided you meet the standards (lights, mirrors, etc...) and register it, you could use it...?

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nicely done :)

 

According to Wikipedia SC doesn't require a safety inspection (which is a bit silly) but means that provided you meet the standards (lights, mirrors, etc...) and register it, you could use it...?

 

Thanks :D

 

The thing is, the engine used is about 190cc I believe, and technically mopeds must be 50cc or below - though without an inspection, I'm sure I can get around that. I'll call up my DMV soon :)

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That looks fun, how do the brakes work?

 

 

 

 

Also I ride my 4wheeler all the time without a helmet but yeah... you should wear a helmet!

 

:P

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Dude, only an asshat cop would ticket you for than, ride it around town and I really don't think you would get a ticket out of it. Ride it, use hand signals just make sure you have break light and something that vaguely resembles a headlight and you are golden.

 

 

Where a helmet you idiot! Seriously, if you think you will be ok if you wipeout, your skull has never hit the ground at 20+ mph. It freaking hurts and honestly you are lucky if you don't end up with a permanent brain injury.

On something with that small of wheels if you hit ANYTHING you will eat s**t so fast it will make your head spin. If you hit something as small as a cat I would bet you will go down and go down hard. (please don't hit cats though, It will make me sad.)

Edited by gabrieltessin

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This is why you should never leave an engineer alone for longer than 30 minutes. Odds are something is going to be modified to hell and back and will either kill someone or make life easier. :lol:

 

Nicely done though, you should make me one so when I have to park damn far away from my first class I can get there in record time. :D

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This is why you should never leave an engineer alone for longer than 30 minutes. Odds are something is going to be modified to hell and back and will either kill someone or make life easier. :lol:

+1 on that ROFL

 

You gotta say, out of all the engineering fields, mechanical looks to be one of the most fun ones =)

Edited by crazian

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Nicely done though, you should make me one so when I have to park damn far away from my first class I can get there in record time. :D

This is the reason I keep a BMX bike in the trunk of my car :P

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