Someday, some way, I will create this masterpiece.
The basic idea, is to make the ultimate homemade, one-man, off-road kart/buggy or whatever you want to call it. Now obviously, there are karts you can buy that use snowmobile or sportbike motors, complete with ECUs, limited-slip differentials, etc. and honestly there's no way I'm going to make something to compete with that. However, what I can set out to do, is eclipse everyone else's home-built efforts, simply by thinking big. As in, 490cc big.
Let's start from front-to-back. The front wheels (and indeed, all the wheels) I think should be 12-inch rims, basically like you'd have on the back end of a 65cc KTM or something. I might use disks or drums just depending on what I can get my hands on, disks obviously would work better, but then drums never develop fluid leaks (this was a problem with the front disk on my dad's '86 Maico). Anyway, the front wheels are going to have independent suspension, and I don't see why a nice pair of piggyback Ohlins like you'd get on a late '70s Husky wouldn't do just fine in that role. They would be configured to "lay down" as they compress, just like in a bike, except they lay down laterally instead of longitudinally.I'm looking for at least six inches of travel, and hoping for more like eight to ten.
Steering is something I haven't entirely worked out yet, simply because I can't honestly claim to know how that even works, but hopefully by the time I get an engineering degree and start work on this project, I'd have that figured out. But, obviously there's not going to be any power steering or any of that nonsense, I want this whole thing to as simple as possible, so anything that goes wrong can be fixed with a brick, and a piece of string (to steal a line from Top Gear). Throttle, brake, and clutch will be controlled with foot pedals, just like in a car. The throttle and clutch pedals will be simply hooked up with cables to the engine, which sits behind the seat. The brakes... well I'll figure that out when I get there. The seat itself will have to be one of those very supportive seats that holds you entirely in-place, with a harness like you'd get in a real performance car. Doesn't need to be a big name-brand like a Sparco or Recaro, just something that works well and doesn't cost $1,000. Gear shifting is simplicity itself, the sequential transmission from the 490 Maico will still be used, and a hand-operated lever will be hooked up with linkage to the shaft that's normally connected to the foot-shifter on the bike. Push forward on the lever to down-shift, pull back to up-shift.
That brings us to the engine. Ah yes, the good old 490 Maico engine we all know and love so much. Of course there's some variability in this, depending on what I can find - the main thing is that it be a big-bore Maico engine, roughly between the years of 1978-1983, just so long as it's big and air-cooled. This engine will simply be pulled right out of the bike, and placed into the kart directly behind the engine, facing forward, and probably tilted a bit so that the cylinder axis is vertical (this reduces the amount of space it will take up). To start the thing, I plan on simply standing next to the kart and kicking it over, like a boss. This will probably mean putting the compression-release lever on a frame rail nearby for easy access. Depending on how the ergonomics work out (for example, if the kickstarter interferes with the rear wheel) then I may have to do some dancing around to get it started, I really would rather not deal with a battery. Of course the gas tank will also have to be located above the engine, because I don't want to mess around with a fuel pump, so that will probably just find its way being mounted on the frame above the engine. I plan on using the stock pipe.
The rear wheels are (obviously) going to be driven by the engine. It will be hooked up via a chain just like normal (albeit shorter), but instead of going to the axle itself, it will connect with a differential, taking the place of the bevel gears normally found on rear diffs. The torque thus split, the power is then transmitted to the wheels separately, which are mounted on independent suspension just like the fronts, again probably on Ohlins or some other kind of shocks intended for dual-shock long-travel bikes. Wheelbase is 6.75' in my preliminary sketch, hopefully I'll be able to work that down a bit, because I'd like to be able to get it in the bed of a truck, provided the tailgate gets left down, and the truck I intend to get has a 6.5' bed (not counting the tailgate). It's still a little too long because of overhang, but I think I could probably find some inches to trim away. Width is not really an issue, somewhere around three feet, maybe a little more.
So, any questions or comments? The intent for this thing is to be the ultimate dirt/gravel road terror. I'd like to use this thing for blasting down fire-roads basically like a rally car, except it can be much more easily transported and would cost a lot less than buying an Evo and thrashing it around in the middle of nowhere. Plus I think performance would be better than the Evo as well given the power and weight we're dealing with, I don't see this creation being over 500lbs. I do anticipate the front wheels might have a tendency to throw rocks at me, particularly during over- or under-steer, so the design (such as it is so far) includes some aluminum sheet metal, which will either be painted red with a big yellow slash (imitating a '77 Maico) or simply left as bare aluminum with a giant Maico logo on it, like the early '76-and-earlier aluminum coffin tank Maicos.