I just finished my first motored bike build- a "Black Stallion" 66/80cc from Kings Motor Bikes. It fired right up (thanks to all here for your excellent tips in many different posts!) and ran well. For my first ride, I kept it on the down-low to help break in the motor. I probably did not exceed 15MPH, and rode around our block a couple of times (about two miles total). One poster recommended two slow and easy 15 minute rides, followed by complete cooling off before riding again. Nothing has blown up, so I guess he was on the money.
One thing I have to say, if you guys are putting these things together in 3 to 6 hours, you must really have it down to an art! It took me one 4-hour evening session and an 8 hour day session to finish this one off! But then, I'm a perfectionist, didn't have all my tools at-hand, and had continuing interruptions with phone calls, TV show breaks, meals, etc. I still need to install the chain guard, but that'll have to wait until cooler weather. And I didn't coat the inside of the gas tank. It's downright U-G-L-Y, and I plan to replace it with something nicer looking.
I could not restrain myself at the end of yesterdays ride (the second of the 15 minute rides) and cranked it wide open to see what it could do. As it built RPMs, it passed a certain range and the entire bike began vibrating like the engine was totally mis-balanced! The gas tank loosened and shifted, and I had trouble keeping my hands on the handlebars! I dropped RPMs, and the vibration went completely away. I tried doing this several times, and each time I crossed that certain RPM barrier, the bike would go into wild vibration!
I'm thinking this is -NOT- normal. I'm also wondering if it could possibly be one of the internal needle bearings being either out of tolerance or worse? Or is this normal for these engines to do this? If not, is there a fix? I guess I can restrain myself from cranking down on the throttle- it certainly moves fast enough before it hits this rough throttle range. But the vibration is so bad, it does concern me. It concerns me a LOT!
My build consists of the Black Stallion and a Wal-Mart "Cranbrook" $84.00 bicycle. Real el-cheapo transportation for around the neighborhood! It fits in my shed next to my Harley Ultra quite well! (And to think I wanted a golf cart!)
-Web