First off im new to the moped world and just getting into repairs. I recently got a suzuki fa50 shuttle. It run very good, runs me around 25-30 mph depends on the hill grade, lol. I just replaced the tires w/ new tires and tubes, and then took it out for a test ride. After about the 3rd mile the rear tire locked up for a split sec. and the engine stalled then i coasted to a stop. I wa terrified that the engine blown, i dont trust the oil injection system much, want to convert it to mix someday, I then pulled the brake/clutch and hand turned the kick start. It went smooth so i guess the engine didn't seize. i rolled the back tire to see if there was interference..nothing! So i tried to start it up, i was only like 2 blocks from home, and rode it like a baby home listening for any new noises, everything seems fine. I took the rear tire off thinking the back brake pad may off fell apart but its all there. I decided to drain the gear oil, which is only like 150 miles old and its a dark grey color, i didnt see and metal fibers or chunks in the oil, also used a magnet for good findings, still nothing. I'm not to sure about taking the gearbox apart, dont have the courage yet, lol. Anybody have any ideas or opinions? Oh and while im at it how do i adjust the fuel oil ratio on this machine? TY for any responses.