50cc vs 80cc?

K

kevinkrg6

New Member
First off, I know it's not truly 80cc.

I have a mountain bike (24"), and I've seen online that someone with the same exact type of frame fit a 50cc engine almost perfectly. If I choose an 80cc (66 or whatever true size) instead, will it be much larger?

I'm just wondering if there is a considerable size difference or not. Help greatly appreciated!
 
Well the only differece in the size between the 48cc and the 66cc is the jug or the part of the motor with the cooling fins and the piston size other then that the are the same size. Some of the 66's come with just a slightly bigger carb but not much to make a difference.
 
A huge thing is legality - many states have a 50cc limit on street legal bikes.

The crankcase is all the same size - though you'll have different head bolt sizes going into it (if I remember right).

I actually think the carb is the same on most (when talking NT), just jetted differently. There is the 66cc NT Speed Carb designed for the 66cc/80cc motors.

The difference to me was 5MPH stock, and way better acceleration.
 
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So you guys didn't really notice a huge difference between something like the pocketbike engine (50cc) vs the larger china dolls?
 
I don't think any of the China girl two strokes have the displacement stamped on them anywhere. A law man cant see the difference between a 50cc and a 66-80cc without and engine teardown, micrometer and dial indicator.
 
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