Ever Wondered How To Build a Racing Lawnmower? This YouTuber Did It for $25MotorBiscuitRahaan MazumderThu, September 17, 2026 at 12:30 PM UTCAdd us on GoogleIf you want to go racing on an absolute shoestring budget, you don't need to search the classifieds for a beat-up Miata or a high-mileage Civic. Real backyard gearheads know the ultimate low-budget thrill ride is probably rusting away behind your dad's shed: the riding lawnmower.In a brilliantly chaotic guide to grassroots motorsport, Dave—the mechanic behind the YouTube channel mycustomgokart—decided to document the entire process of turning a ditch-find lawn tractor into a completely unhinged racing machine.Now you can't just take any old yard machine and expect it to do burnouts. Before the sparks started flying, Dave laid out the golden rules for sourcing a donor chassis.AdvertisementAdvertisement"First and foremost, you're definitely going to want to find a manual with a five- or six-speed gearbox," he explained. "I don't believe you can hop up a hydrostatic mower to go much faster than they already do".Beyond the transmission, he highly recommended finding an older model with "all metal body panels" to make cutting and welding modifications significantly easier later on. Following his own advice, Dave managed to score a rusty, 11-horsepower, five-speed Craftsman tractor out in the middle of nowhere for a grand total of $25.The "Controversial" Transaxle FlipTo turn a top-heavy tractor into a low-slung racing kart, you have to drop the ride height. Instead of engineering a complex new suspension system, Dave used a classic, albeit highly debated, backyard hack: he physically unbolted the rear transaxle and flipped it upside down.While this perfectly lowered the frame and allowed the forward gears to function normally, it created a massive lubrication problem. The factory seals on a mower gearbox were never designed to hold fluid while upside down."In an ideal world, you would run some ATF or some gear oil… but here's why I don't use that," Dave noted, directly addressing the controversy. "Once you flip them, you now have two shafts upside down that aren't meant to seal… so if you don't care about ATF gear oil dripping all of the time and you feel like putting a cap on your transmission, then go for it".AdvertisementAdvertisementInstead of using liquid oil, he packed the entire gearbox housing with two massive tubes of high-temp grease to keep the gears lubricated without leaking all over the track.The $60 Steering Cheat CodeOlder Craftsman and Murray mowers are notorious for having horrifyingly sloppy steering. Trying to navigate a corner at high speeds with the factory tie-rod setup is a guaranteed recipe for a rollover.To fix the massive dead zone in the steering wheel, Dave utilized his absolute favorite hack: a cheap go-kart rack and pinion kit."By far the best thing you can buy for this cheap mower," Dave emphasized while showing off the new hardware. "I believe this was $60, comes with two U-joints, the rack, tie rod ends, steering wheel… just about everything you need to hook it up".AdvertisementAdvertisementAfter welding up a custom steering column and bolting on some incredibly narrow, "Not for highway service" tires to fit under the freshly chopped hood, the $25 ditch-find actually looked like a legitimate, low-slung race kart.The Inevitable Dirt Jump CrashOf course, building a sketchy racing mower is only half the fun; the real test is the shakedown run.The initial test started flawlessly, with Dave ripping burnouts in the street and carving through the grass. But confidence is a dangerous thing. Despite having a completely rigid front axle with absolutely zero suspension travel, Dave decided to aim the mower directly at a steep grassy embankment."Can you actually hit a jump like full speed, 84 miles an hour, and then you blow the front end out?" he joked sarcastically after launching the heavy steel mower completely airborne and slamming it back down into the dirt.AdvertisementAdvertisementThe brutal impact immediately snapped the steering components, rendering the mower totally uncontrollable. Moments later, the transmission belt began pouring out thick white smoke, signaling a complete mechanical failure.Taking it to the Real Race TrackIf watching a modified Craftsman catch air inspires you to build your own, you might want to look into actual sanctioned racing events.According to external guidelines set by the U.S. Lawn Mower Racing Association (USLMRA), turning a yard tool into a race vehicle comes with strict safety rules. If you want to enter an official prepared class, all cutting blades must be completely removed, brakes must operate on at least two wheels, and zero-turn mowers are completely banned from competition. Furthermore, all racers must use a tethered kill switch—meaning if you get bucked off your mower during a jump, the engine automatically shuts down before the tractor can run into the crowd.As for Dave's completely broken Craftsman?AdvertisementAdvertisement"Throw it into a pool or the ocean with a brick attached," his cameraman suggested.