50cc or 80cc

philymitch · #1 10-10-2009, 12:58 AM

is there a noticeable difference between the 50cc and the 80cc. I went and ordered the wrong motor now I am stuck with the 50cc I hope it works.

**Bikeguy Joe** · #2 10-10-2009, 08:32 AM

Very little difference, some say the 50cc is smoother, I can't tell.

caprirs302 · #3 10-10-2009, 10:11 AM

I have one of both, and even though it may just be my particular motors, I can see a HUGE difference. Basically to the point that the 50cc isn't really worth the time. Again, i may just have a slow 50cc motor, but it accelerated much slower than my 67cc and didn't reach anywhere near the top speed.

You would probably be happier with a 67cc motor.

philymitch · #4 10-10-2009, 11:03 AM

thanks for the info guys. my last motor was an 80cc. I had thought they sent me the wrong motor but It was my fault i ordered the 50cc. oh well we will see how it pulls me around

momentummotorgroup · #5 10-10-2009, 12:55 PM

well, the 50cc is a good thing simply due to legality. In most states, the 50cc and under class of engine doesn't require license, registration, or insurance. anything above that and the state wants their cut. I have a couple bikes selling right now, and whereas the 66cc (they call it 80 but that's BS) has more pull and out the gate torque, the 50cc slant head that I have is fairly comparable in speed and doesn't vibrate nearly as much as the 66cc, which is nice as it's kind of a pain in the butt to stop and tighten stuff up while you are riding..

**2door** · #6 10-10-2009, 04:28 PM

I probably shouldn't comment here because I only have the bigger engines but I will say that they are all as different as night and day. Two of them are from the same vendor and one from another source. The engines, outwardly, are identical. No difference that the eye can discern. The difference is how they run. One, the oldest, and by the way, the most expensive, will top out at about 24mph with my skinny 140 pound butt parked on it and a 44T sprocket. The next oldest runs a little better and has almost no vibration. It pulls through a 41T and is faster on the flats. Then we have the third one. It simply hauls. Vibrates like a, well, a vibrator, and will pull me from a dead stop, no pedaling and also running a 41T, has a confirmed top speed of 34. (I hate to say that 'cause it will surely start something) Nevertheless, it does run good.
So...I was curious. "What is the difference between these three engines?" I asked myself. Same bore, same stroke, same carburetor, ignition, fuel, etc. What's so special about this one engine that makes it run circles around the other two.
Ignition Timing. I made an adapter to fit my automotive cam degree wheel and used it to check magneto rotor (magnet) position relative to the coil based on piston position or top dead center, TDC.
The best running engine is a full 2 degrees advanced over the next best one and 3 degress over the weakest engine. My conclusion: The factory cuts the keyway in the crankshaft that positions the magnet roughly, or, 'in the ballpark' one, two three or possibly more degress difference probably isn't much in the Chinese version of quality control, but it apparently has a huge impact on the way an engine performs.
Anyone else ever taken a look at magnet position, timing, on their engines?
This discussion has been up before but there were never any real conclusions or confirmations so I'm relighting the fire.
Tom

momentummotorgroup · #7 10-10-2009, 05:51 PM

i would love to know, because I rode mine for an hour earlier today without a hitch-she started right up from a cold start- then 20 minutes ago I went out and she won't turn over..same weather conditions, same temp outside, same gas, oil, weight, etc.