I Bought the Cheapest and Most Expensive Motorized Bike kits from Amazon

The fact that this guy built bikes for wallmart makes a lot of sense. Now I know what the kind of person that installs a fork backwards on a wallmart bike looks like.

Had one of these in high school. I tuned and polished the ports, and sanded down the jug for higher compression. It was an absolute riot and weighed in at only around 50lbs, so it would do about 35mph on the straight. Wouldn't want to go much faster than that on bicycle tires and a single tiny disk brake, but I loved it!

When I was 13, I built a 16" motorised bike with a 31cc 2 stroke whipper snipper motor. That was driven via a machined shaft onto the rear tyre. Would do 63km/h (Australia) and then..... went N2O injection with some creative engineering and could get up around the 80km/h mark. Looking back that was nuts.

keep in mind that the engines require the cold air running over them (from the bike's movement) to cool themselves. They likely could have lasted significantly longer on the road

I had one of these in college and rode them all around campus! It was AWESOME! I learned so much about 2 strokes and Carbs (I am a Software Engineer so no school on these) I even re balanced the crank shaft! These things are so fun!

Durability test could've been better. Engines broke bc they weren't being cooled.

I've had mine for 14 years wit no issues! Take your time building these !

As a bigger guy myself, I think I have to finally point out the obvious size/weight difference between Sean and Craig when it comes to these head to head battles. Sean needs to be wearing a backpack full of ballast to even the scores! Big guys unite!! Thanks for the laughs guys!

That durability test was wack. These are actually pretty reliable engines. I've put quite A few miles on my last one and the piston still looked brand new before I sold it. You guys ran HALF the amount of oil you should be running for break in, that failure is clearly from heat... the piston got too hot and the high rpms broke the molten piston... Disconnect the radiator on a brand new KTM and you'll get the same result....

I’m 13 and I have the same cheap motor kit from Amazon on my bike currently, I have learned so much off of these little engines it’s insane and it’s my gateway into motorcycles in general and I have 243 miles on it so far and more to come. There awesome motors for people getting into engines or just trying to have a little fun just make sure you research a lot about them or they will break faster than they can ship from china

The fact that the cheapest motor stayed on the frame with only one motor was a shock! You normally have to check the tightness of the mounts because of the vibration from the engine. I've had a 2 stroke fly from between my legs this way. Be safe y'all!

I built one of these kits three years ago. I got a steel cylinder jug and high compression head with a real crank case and piston kit from Bicycle Motor Works in Pennsylvania. It took me two months to build the bike and make it a "look-a-like" 1910 Indian. I've taken it to shows and won a few trophies and such... runs out at 48mph (scary for what is actually a bicycle) and is super fun to cruise around on. I have well over 500 miles on it and sill enjoy riding it all the time. - these bikes can be a he'll of a lot of fun!

I have built several of those bikes. I actually went through 3 engines on one bike. But, set up properly, I did get over 2000 miles out of one of the engines. Not at full throttle, I kept my top speed to 20 mph. There is one part on those bike kits that will kill you, and that is the clamp on chain tensioner with the little plastic pulley for the motor chain. I had one get sucked into the rear wheel once, it destroyed the wheel, locked it up, and I crashed hard, onto concrete. I was riding in a bike lane, and was fortunate enough to crash to the right, onto the sidewalk, instead of to the left into traffic, where I would have been crushed by cars. NEVER use those things. You can get tensioners that mount to the motor. And that rag joint rear sprocket is junk as well. No possible way to keep it centered. You can get a clamshell rear sprocket mount that clamps to the rear wheel hub. You absolutely HAVE to have a front brake with these things. The coaster brake on a Walmart bike is completely worthless.

Fuel to oil ratio should be 16:1 for the first two tanks and 20:1 after the break-in. I've built and sold 21 of these bikes in the last two summers

Crazy thing is that's exactly what my job is right now as a Contractor building bikes at multiple Walmarts! Up to about 25 to 35 a day and it's the most lucrative thing I've ever done and I love it!

Wow, coincidences... I also worked building Walmart bicycles in the late 80's. EVERY bicycle out of the box had loose spokes, NO shifter/derailleur or brake tuning, so they had a 60+% return rate up to that time. After 1 yr, the return rate was just over 4%. The manager was still only worried about units/day assembled because his bonus was based on sales alone at that time (Christmas WalMart bike sales are insane and he wouldn't authorize overtime). At that time, they did not penalize for losses due quality issues which they wrote all the returns up as QA issues.

One reason I love mopeds, is because they are still true to the original motorcycles. Simple engine with one gear, and pedal cranks... WHAT YOU WANT IS A WHIZZER.

The fact that Sean’s came stock with maxxis tires is insane 😂

I had one of these as a teen. It was the “80 cc” (66 stamped on the side) and it lasted me years. I rode that thing everywhere and wide open throttle the entire time. Mine lasted for what seemed like an eternity. I ended up trading it for a pit bike and the guys I traded to rode it for years after that. If you mix the gas and oil properly and do regular maintenance, they last forever. The fact they sat on a trailer revving with no air flow on the cylinders, which have fins specifically designed for airflow, is what caused them to fail. Still cool video though. It was like a gateway to me riding motorcycles as an adult. I would recommend to anybody to build one of these. They are so cool.

I bought a true 49cc Grubbee 2 stroke kit and the only big problems were the stock intake tube, which leaked and the stock chain, which stretched and had no tensioner. Once I replaced the stock intake with a cast tube, replaced the stock chain with a 410 and installed a spring loaded tensioner, the bike ran great. There's no race for the crank bearings, so Grubbee recommended running the engine at no more than 15 mph for 5-600 miles so the crank bearings would fit themselves into the crankshaft! I still run it rich at 24:1 with primo 2 stroke oil and NO problems after 15 years and over 1000 miles!-John in Texas