49cc 50cc 2 Stroke Racing Engine Motor, Single Cylinder Pull Rope Start Motor, 2 Stroke Gasoline Engine for Dirt Bike Pocket Bike ATV Scooters, Pocket Bike Engine Kits

Pretty good got no complaints. How do I determine the front sprocket size so I could change it to a 420 pitch? That’s the only problem I’m having anybody has some info please share.

I bought this to replace the engine on my daughters' 4-wheeler. The mounting points were different so I made my own mounts from 2 pieces of 1/4" x 1" flat stock, then used 20mm U-bolts to attach them to the frame. I was able to reuse the throttle cable from the old 4-stroke setup. Once it was all bolted down I poured some 25:1 gas in and it fired right up. Engine seems strong (for its size) and has good throttle response. If you're looking at this for the same project I was, I can confirm it does fit the X-pro 40cc transmission. I opted to use the old transmission because it has a 5.5 input revolution/1 output revolution, whereas the transmission that came with this engine was a 3 input revolution/1 output revolution, and I wanted to make it slower for my kiddos. I'm sure if you use the transmission that comes with this engine it'll boogey pretty quick. Will update if anything changes, but so far I'm pretty darn impressed for the price.

Haven't mounted it yet but very concerned about the engine mounting situation. 4 very small screws, if this thing has any torque at all it will fly off whatever it's connected too

Had to use the old trans for my China dirtbike. Engine ran great on 32:1 on first start up! I primed the engine with oil prior to adding fuel on first start up to prevent pre mature ring failure. Engine is impressive. But now doesn’t stay running on idle. I presume I need to adjust the carb or the gas tank Was dirty prior to new engine. Either way, I will be investigating before making false claim on a poor engine build

Absolutely stay away nothing but problems waste of money