Yup what a carb does mainly is dumps the raw fuel into the cylinder, its the cylinders job to break down the fuel further to it'll burn quicker and cleaner

 

Next time it rains when your in your car/truck dont put on your windsheild wipers for a minute. The rain slowly moves up your window because its sticking to the smooth glass surface. Now if that was scuffed up, causing some turbulance it would move quicker and thats what you want.

 

you can polish the intake side of an engine....your engine will require more fuel...a richer mix, because of the reduced atomization of the f/a mix....but....it will run significantly cooler, due to the droplets of raw fuel contacting the piston, plug and cylinder wall. it may not be as dependable, due to the fuel washing the oil off of the cylinder walls, but if done right, it will make for faster f/a flow. it probably would only be effective for high end power, though. all the car racing guys polish up there intake manifolds, they swear by it.

what i want to design is a rotary cylinder head, without a cam or valves. think about how hard it is to turn a cam over......thats sapping alot of hp. now imagine an engine that didnt force air around a valve.....at a certain point in timing, a plate with a slice cut out of it exposes the cylinder directly to the intake....no restriction, no valvespring. kinda hard to explain, but ive got some great drawings. if i had a machine shop, id try building it.

 

your talking a 4-stroke compared to a 2 stroke. They are totally different animals when it comes to cylinder design and fuel delivery

 

That makes sence.. I understand better now, thanks.

 

SO say you have two identical bikes with same mods (pretend they run the same exact way) and you took one cylinder and polished it and left the other one rough. The rougher one would have more power? or burn cleaner or both? If it does why would anybody polish the intake? Also, if you took the polished one and put it back on would you have to re-jet that much?

 

Customfabandweld is right... smaller ports gives more torque, better atomization, larger ports give better breathing at high revs, usually a narrow power band as well.

 

incorrect. smaller ports dont always give more torque. A motor designed that can flow x amount of air can be hendered by smaller ports rather then helped. Look at the transfer on a honda compared to a banshee. Honda has nearly 2x the size and the honda will almost always pull more torque then a banshee. Comparing apples to oranges, but its the idea...

 

I made the mistake about 15 years ago of polishing the entire inside of a street/strip manifold on my hot rod after matching the ports. Needless to say it was given away not long after. The car black smoked, especially when under heavy throttle and ran like crap. I didnt understand why until I pulled the carb back off. There was the fuel just setting there all inside the manifold. When the surface is smooth the fuel drops out of suspension. The worst part about it was it took quite some time to do the work. One of those lessons learned.