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View Full Version : 4 stroke 50cc?

lukerogers94
07-19-2009, 02:36 AM
im building a mini chopper, and im looking at buying a 4 stroke 50cc would this be enough to push me around at say 40km/h?
Affair_driven
07-19-2009, 07:27 AM
Going to need at least double that size.
mike75925
07-19-2009, 07:41 AM
with the right gear reduction maybe, after all, it's not like you said 40 mph.
Affair_driven
07-19-2009, 07:49 AM
40kph = 24.86mph
50cc won't cut it. Reduction will make things worse.
ed1380
07-19-2009, 08:29 AM
why 4 stroke?
mike75925
07-19-2009, 08:42 AM
some of these two stroke 49cc's run pretty fast. with a four stroke seems more readily done. with the added torque, you could run smaller wheel sprocket and still have a decent acceleration. right?
all these older mopeds and small motos run i would say a good 30. depending on his engines tune package.
oscaryu1
07-19-2009, 08:55 AM
49cc 2 stroke would do it.

If it doesn't, add on a CNC lightened and balanced flywheel, rockit 10 degrees advanced timing key, full circle crankshaft, Black Widow 3 stage reeds, big bore kit, port and polished cylinder, NGK spark plug, 2 shoe adjustable racing clutch...

Yeah.
mike75925
07-19-2009, 09:42 AM
that's alot of stuff for 30mph. shoudn't you get like a hundred out of that? ballpark, idk.
Kaptain Krunch
07-19-2009, 10:18 AM
that's alot of stuff for 30mph. shoudn't you get like a hundred out of that? ballpark, idk.

Are you serious? its 49cc, you can only go so far...Even with all that stuff in the end there is no replacement for displacement.
mike75925
07-19-2009, 12:34 PM
true displacement is the easy way for power, aprilia makes a 50cc that does 70, granted with a six speed tranny
lukerogers94
07-19-2009, 10:15 PM
:confused: do you think that a 80cc would cut it?
mike75925
07-19-2009, 10:36 PM
i've had a few 80cc dirtbikes, with four and five speed gearboxes, they topped at 45/48mph and they were about 3/4 life. if thinking bike engine, yamaha's yz85, will come up in all six gears, and top 75mph with a 145lb rider. next would be the kx80 expert.
lukerogers94
07-21-2009, 03:33 AM
why 4 stroke?
not really by choice but it was what i could find, but anyway wouldnt a four stroke sound better on a chopper. anyway i did some more searching and i might be able to get a 5 horsepower or an 80 cc they would push it around much better.
mike75925
07-21-2009, 09:38 AM
if the 80 has a tranny yes, it would be the fastest.