Let me start this thread by saying this: I am an idiot.
Over the weekend, I attended the annual Mansfield Swap Meet in Mansfield, MA. Usually, I am on the hunt for Trans Am parts, and most years, I just end up buying random video games instead. This year, my 14 year old nephew asked to come with my usual crew, and since he's a budding gearhead with a doctorate in small engine-equipped things, he was on the lookout for parts for a vintage minibike project I gave him last year. He's already had a go-kart and 3-4 mini bikes in his short time turning wrenches, always wheeling and dealing like a junior GRM'er should.
So anyway, we were getting baked by the sun, roving the aisles looking for stuff, and there were lots of small engine'd machines and parts for sale. He struck a deal for a vintage Briggs & Stratton 3hp engine, running, for $15, and was happy. Later on, after asking about countless go-kart and mini bike frames and getting absurd price quotes, we came across a group of younger guys with two mini bikes: an old mini Indian trail bike, and a scary-but-cool bike with ape hanger bars and an extended swing arm, and a giant 8hp Tecumseh engine dominating the frame. We asked how much, and they came back at $80, firm. Interesting; it was the cheapest minibike we had seen all day, and one of the coolest. I also just bought a whole, mostly functioning car for $20 more, which is kinda sad. 
We pondered and waffled, and some other guy went over and started asking about it. In most cases, I hate when that happens, but it was educational in this instance. We sat back and watched the guy poke and prod the thing. "Does it run?" the guy asked. "Yeah, but BLOCK YOUR EARS!!!" the seller responded. A couple pulls, and the 8hp Tecumseh roared to life with a deafening howl, but sounded good. "The chain is off because the motor's not aligned, and the throttle sticks", the seller yelled over the noise. The prospective buyer left without a sale, so we went back over. My nephew asked about the mini Indian, but the kid just got it that day in a trade and was asking somewhere north of $500, so we re-focused on the deathtrap. My nephew reminded me that it was worth the $80 in parts alone, and he had a couple other engines at his disposal if the 8hp was too much or unreliable, so we bought it.
Instantly, regret set in.
So, here's some pics.
My nephew with our "prize".
Ignoring my poor garage, check out the weirdness! It has a big whel and tire up front, and a smaller one out back on an extended swing arm. My nephew couldn't ID the frame, and thinks it's a customized build. Note the fart can sticking straight out the back.
Throttle bracket made out of scrap metal. It sorta works, but it's ugly.
That was the air filter. It fell apart already.
I'm digging the ape hanger look. And as an adult, it's more comfortable to ride, too. The forks are a little weird, but they will work.
Looking at the boogery "exhaust pipe", I noticed that the flange has no gasket at all. That explains the deafening volume of the engine. I'll have to address that.
The seller said something about the spark plug wire coming off at random (oh, great!), so I'll have to see about replacing that if I keep this 8HP monster on there.
It has this "idler" gear, mounted on a slot on the frame. My nephew says that this is usually where a pulley would be located, and the sprocket might be part of why the chain is falling off.
I went inside my house to grab a drink and came back out to this: My nephew pulled the motor already! He was looking for a stamping on the engine pad to ID the frame, but there was nothing there. Also, check out that diamond button tuck seat. Coolness! I will have to add a couple missing buttons and re-sew the bottom trim, but it's all there. Seats like this are hard to come by, and can cost as much as I paid for this stupid thing.
So there it is. What's the plan? In August, I'll be hitting up the 24 Hours of Lemons race with the Nuthin' But A Z Thang guys, and there are tentative plans for a 3-way race between this thing and two Whizzer-style bikes. I need to have it done by then.
What am I going to do to it to get to that goal? Here's a small list:
-Purchase and install new throttle assembly
-Purchase and install new brake handle and figure out how to make the drum brake work better
-Mock up engine for alignment
-Make it less noisy
-Clean frame and paint it some awesome early 70's color like metal flake bronze, and paint engine case white
-Replace rear tire (and maybe the wheel) with larger one
-Don't die
If anyone can ID the frame, that would be cool. Enjoy!!!
Milk crates make GREAT mini bike work stands!
This tube is where they cut off the sissy bar. Both sides were jagged like this. 
More evidence of customization. Those boogery welds are part of the swing arm modification. 
The wheel/brake assembly. You can see the brake shoes poking through here. 
On the other side of the rear wheel are all of these spacers. Not sure what's going on here. 
The brake shoe mechanism is fairly simple. There's even some pad material left! That's because the brakes have not worked in a LONG time. The brake lever is from a pedal bike, and was missing some parts, causing the cable to do nothing. But with a new cable and lever, it WILL work. 
I pulled the rear shocks and the wheel for cleaning. The shocks are still good, and the wheel is interesting in itself. It's actually a two piece wheel! I found out the hard way when I removed the six bolts that hold it together while air was still in the tire. 
Luckily, I didn't mess anything up. It's back together and good to go. 
Here's where I might need some help. I am trying to ID the engine, and all the stickers were missing. I found these two stampings: the top being an ID tag on the engine block, and the bottom being the stamping on the carb. Anyone know of a place I can find out what this thing is? 
