Kymco 50 four stroke

[fiscardo]

I have a Kymco Jetix 50cc. It has a four stroke engine and a four speed semi auto gear box.

I don't see many of these in forums or on the net.  I bought it new in Greece and it is very restricted.  I assume this is being done either in the exhaust, the carb or electronically throught the chip.

The susual solution here seems to be to buy a 100cc piston and cylinder kit and a new carb.  I would prefer not to do this but would like to tweak current set-up to try and get it to handle more like the old Honda 50's whih went fine....

Does anyone with tecnical know how have any idea on what I could do?

Best wishes

Nick

[cors50agility]

I would look to relieve the exhaust restrictions first.
The header pipe may be restricted depending on your exhaust valve size.

Then check the inlet manifold and intake valve size variation.
Small intake manifold negates all carburetor mods.

I would have bought a 125cc variant rather than big bore kit.

The 50cc project bike i have seems to have a very limited exhaust header size and exhaust valve size.
The stock carby is adequate for the motor into the upper revs, but the inlet manifold is a limiting factor into higher revs.
The inlet valve size seems adequate for most of the usable rev range.

The cam can always be tweaked and offers a bolt on solution for some of the port/valve combo short falls.

I guess you need to know your motor.