Monster Scooter build

[newrider3]

So a few weeks ago, one of my roommates from last year brought his electric Razor scooter to a bbq at our friend's house. Everyone had a laugh screwing around on it, but the thing can't even carry him up the big hill we live on. I got to thinking how I could build something way better, and on a trip home I realized I already had all the parts laying around.

I started with an old ghetto minibike frame I fabbed from junk bicycle parts, and a homemade bike wheel kick scooter I had also built a while back. Cut them both in half, and welded the back of one to the front of the other. Then I fabbed up some triple-clamp style forks and a long gooseneck out of 3/4" black pipe.

Going to be running 145/70-6 knobby tires, and a converted Briggs Quantum mower engine. I get these things for free all the time, so a couple hours in making it work are no big deal. The PTO had to be machined down to 3/4" so I could use a cheap centrifugal clutch, it turns out we have a full machine shop on campus that we can use for free with help from the old timer that runs it after a safety test. I also took a Quantum cylinder head with me that had a botched mill job, and cleaned it up with a big fly cutter.

Here's a few pics.

 

[landuse]

Nice. You should have some fun on that thing

 

[exenos]

Oops, Caps lock

How much did you take off that head? Will you need to run 93?

 

[newrider3]

I'm not quite sure, the last pass we made was 5 thou, but I don't remember how much we took off when I was screwing around with it on my high school shop mill with the wrong tool. Probably somewhere between 25-40 thou total. I'm not too worried about running high test fuel, considering the low compression these old design flatheads start out with I think it will be ok.

 

[landuse]

nICE. yOU SHOULD HAVE SOME FUN ON THAT THING

Oops, Caps lock

How much did you take off that head? Will you need to run 93?

He he. Don't know what it was doing on. Thanks

 

[Sam-Q]

I really like your project. I am slowly building a scooter with a similar concept as what your doing. The good thing about something like this is you can take it over all sorts of things. The Go-Peds have the support but most of them are friction drive and can't even go on grass.

Please keep us updated on the project.

 

[newrider3]

I was going to go down to the machine shop today to mig weld the dropouts on the front fork, but one of the club officers for our Formula SAE team was in our shop so I used the tig welder. Probably the nicest welds this thing will have on it. Was able to finally get it into a roller tonight.

One issue I've had with the Quantum engines is the intake arrangement. The stock intakes are usually plastic, so I can't re-use any part of them. Also, the mounting holes are extremely small and delicate. I had an intake manifold fabbed up to bolt right on, but the mounting screw broke off in one hole. I've already had another block strip out both mounting holes. There's really not enough meat to drill and re-tap, so I decided to just tap the port for 1/2" NPT, and use some pipe fittings to build a manifold. It's not the best arrangement, and leads to a little convoluted plumbing, but I think it'll work OK.

 

[Nodroz]

Looking good! Nice weld over there.

I don't quite understand why you made that weird looking intake manifold? Could you please explain?

 

[newrider3]

I had a custom intake made that brought the carb out in the usual location at the rear of the engine, but these engines have such small and weak mounting holes/screws I stripped out one hole, and broke a screw off in the other. There isn't enough material around the port to re-drill and tap, so I just tapped the intake port. The threaded fitting had to come out that direction (through the blower housing) because a 90 degree fitting to bring it out the back would've been impossible to thread on with the flywheel and coil mounting posts in the way.
It looks worse than it really is, it's not much longer than a stock manifold on something like a Tecumseh.

 

[Nodroz]

Oh, I understand. Thanks for the explanation! Can't wait to see it going!