Re: Can you unbridled your 48cc engine ?
this guy with the big words......
I wouldn't say these engines are "bridled" as much as they are extremely cheaply made. Don't get me wrong For ~130 bucks your getting a **** of a deal. like some moped engines which have a restrictive intake that allows the moped to pass regulations and still haul with minor modifications. This is not to say you cant get a small power increase with DIY mods and cheap upgrades.
First things first, replace your spark plug wire(~$8), if your spark plug came with no nipple on it buy an NGK B6HS(~$4), its arguably the best all around plug for most conditions. This will really keep it from sputtering at higher rpms, starts will be easier and it will idle far better.
If i would consider anything a bridle it would be the stock air box. Some of the grubees come with a red one which is not as restrictive, but if you get a black one drill a bunch of holes in it to take away some of the vacuum at higher speeds.
Go with a fully synthetic oil(not a blend). -Increases all around engine performance.
Increase your compression by removing your head gasket or base gasket depending on where you want your power. Remove the head gasket if you want a little more power all around. If torque is a big issue, remove the base gasket(it changes the valve timing in favor of low end torque). I say or because most engines will hit the top of the head if both are removed, but if you try it with both and the piston doesn't hit the plug or head (and your willing to take the slight risk) go ahead and take off both gaskets. If you want your engine to stay clean but some gasket spray, its about 8 bucks but
its good stuff. I have no head or base gasket and my engine has had no leaks for 400 miles.
Though it takes a little longer, matching your exhaust port with your exhaust flange using a rotary grinder or a file can help as well. If your really willing to dig into you engine you can match the transfer ports as well as the intake side.
Just my two cents, 90 percent of my customers who buy 50ccs want to replace them with 80s after they try out my bike( i started with a 50 as well). They have at least twice the torque as the 50s and about a third more power even at the high rpm. And no cop carrys around a syringe to measure displacements so don't worry about the 50cc and under law.
Either way your gonna love it.
-Phil in CT