Notes from a First Time Builder of a 66/80cc

Discussion in 'Motorized Bicycle General Discussion' started by Russ McClay, Feb 1, 2013.

  1. Russ McClay

    Russ McClay New Member

    Jan 21, 2013
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    Some notes from my first build:

    • 16:1 maybe for the first liter. 24:1 for the next two or three tanks (2 liters per tank). My motor was running great at first but then starting to bog down and there was too much smoke...on the second tank I went to 24:1 (actually a little less to dilute what was left in the tank. After about 5 miles of riding...noticeable improvement...
    • Acceleration cable...make sure it's not bound by ties or too tight bends, needs to be free with enough slack near the handlebars to compensate for turning left and right. The handle should turn freely. If not take it apart, study it, and re-assemble.
    • Chain alignment is the most important thing: the rear sprocket cannot wobble at all...check the rubber rag washers carefully to see which one is the most even thickness and use that for under the sprocket.
    • Check the chain constantly for the first 50 miles. This can be quite dangerous, though: looking down at the chain while riding.
    • Make sure the bike has good brakes...replace the pads if it's an older bike. Teach yourself to instinctly released the clutch and grab the brakes.
    • Get lights if you ride at night.
    • Tighten bolts after every few miles...not too tight, especially the muffler to head bolts, the manifold bolts, the carb connector, the sprocket bolts, the tensioner bolts, the mount bolts, the head bolts...spark plug. I over-tightened the sprocket and tensioner bolts stripped them (and literally broke some of them in half). Bought equivalents from a local Taiwanese hardware store (slightly better quality).
    • Properly inflate tires. If you're a lightweight like me (130 lbs), you can use less air pressure which means a smoother ride.
    • Do many many short test runs, maybe only a few hundred yards each time. Then stop the engine and look over everything, especially the chain. Check the chain! Get it right!
    • Add an inline fuel filter and replace the factory fuel line with better tubing.
    • Get a speedometer. Mine cost more than the bike (bike was $25, speedo was $30 (nice German one, It is extremely useful to know your speed and the distance you've traveled.
    • Ride like you are on a bicycle, not a motorcycle.
    • When climbing steep hills and if the motor starts bogging down, it's OK to pedal to help the engine. It likes it!

    * * *

    Now for a few remarks:

    In my build, the chain _was_ the main issue. I say "was" because I think I've finally got it adjusted to the point where I trust the rig on longer journeys. I also had some problems with 4 cycling and bogging down. I think this was because I used too much oil in the mix. The second issue was getting the carburetor dialed in. My original float had a leak. If you see fuel pouring out of your air filter, this is probably why. I got a replacement from the seller. He didn't bother sending me just the float, he just sent me a whole new carb. lol Nice to have spare. With the carb, I had to find the sweet spot adjustment between the needle valve setting and both ends of the cable which have adjustment mechanisms. I still have some tweaking to do with that regard, but I'm 97% there.

    * * *

    I was hit night before last by a taxi. Low speed collision. He clipped my rear wheel. I was thrown off the bike which still had the clutch engaged and, with the twisting of the handlebars after falling down, the engine was racing. The impact also dislodged the tank which pulled the fuel line off. So gas was going everywhere. I was back on my feet quickly (thankfully) and shut the gas off. The motor by this time had died. The rear wheel was damaged so badly that I couldn't even push the bike. Fortunately I was on my way to a bicycle shop to have the bike chain replaced. I walked the bike with the rear wheel lifted to the shop which was close by. I bought a new rear wheel. I dreaded re-doing the rear sprocket has always taken me an hour or so. But with the young bike mechanic we did it together and it took 15 minutes. It was night time when this happened. I had no lights. I was on my way to get lights which I have now. lol

    Lesson learned from the accident: ride like you are on a bicycle and yield to all other vehicles. Wear a helmet (which I was and which I don't like).

    And finally...tonight I did some riding back and forth on some straight streets that have little traffic...and the bike is starting to really sound good! It's true what I've read here...that after a good break-in these little motors get better! Having said that: I am prepared for anything to fail at any time. That's the nature of the game of these China Girls.

    This hobby has brought me great joy! I love my bike.



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  2. Dan

    Dan Staff
    Staff Member

    May 25, 2008
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    Hello Russ.

    Glad you were OK after the accident!

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