Spring Fever: Amazon Diesel-Powered Mini Bike Pt. 2

We say you have to break a few eggs to make an omelet, and if you tuned in for Part 1 of our Diesel Mini Bike Build, you saw us hack a vintage mini bike in two, take a file to a spinning crankshaft and run up a wicked cart on Amazon.com. All in a day’s work around here, but even with just a few big pieces coming together, this project was shaping up to be more than just a ridiculous idea.

That being said, all we really had was a roller with a dirt-cheap diesel engine from Amazon shoehorned into it, and it would take some real work to reverse the rotation of the driven clutch. With morale low and enthusiasm from management dwindling, we gambled the last cent of our mini bike budget on a go-kart reverse gearbox from maXspeedingrods.

We've become a household name for making the cheapest turbochargers money can buy, so you know we're in good hands. Our Vevor driven clutch would mount directly to the gearbox, and the box would be mounted in the bike with supplied bracketry. A 10-tooth sprocket comes off the gearbox, so we'd shift the box into reverse and throw the shifter in the trash—problem solved.

Except it didn't exactly fit. The driven clutch interfered with the frame, and there wasn't really a good way to move it. So we moved the frame. We axed the rear leg off with an angle grinder and shaped a new one out of some 1-inch tubing. Yeah, it's 1/8-inch off from the tubing used on the rest of the frame, but you'll never see it, and everything fell right back into place.

The Fuel Tank: A True Marvel

I don't foresee us running the diesel mini bike hard, but if you've never witnessed a belt failure on CVT, take my word that it can be quite violent. So, in the spirit of not getting peppered in the nether regions with belt parts, a custom clutch guard was in order.

The guard is made from the same bits of 14-gauge 4340, and we did all of our welding with 5356 rod. It's nowhere near as complicated a project as the fuel tank, and you could build the same thing at home with basic tools. The most entertaining parts of this guard are the two domed pieces that cover the clutch bolts.

The Final Reveal: Get Ready to Lose Your Mind

If you haven't spent much time around old-school mini bikes, I'm telling you, go scoop up some garbage on Marketplace and put it together. The parts are dirt-cheap, and there's zero reason to chase perfection.

Also, everything motorcycle-related just becomes infinitely cooler when it's tiny. A crude exhaust, a backwards dirt-bike fender or even a sprung seat over rear shocks, the rules just don't apply here.

From here, we're ready to tear everything back down and splash some color on this hog, so be sure to tune in next week for the big reveal.