port and polish head?

[400thacker]

I am about to aquire a couple extra heads and want to try and port and polish them myself. has anyone on here ever done it before? I mean I am sure if you take it to extremes you can mess it up but are there any paticular areas you have to watch out for? I was going to use a dremel tool with grinding stones then polish it down for a smooth finish.
Another thing, is it really worth it? is it a significan't power gain? comparable to cam or what? I just don't know much about doing it on a atv but have worked on mustang heads before. any imput is greatly appreciated.
atleast I have extra ones to mess up!:D

[drew416ex]

I havnt done it myself but the gains are worth it especially when combined with a bigger cam and high compression.

[drillteamleader]

as far as the port is concerned, just smooth out the casting on top and sides of the intake. concentrate on smoothing the transition around the valve seat, that is where the most gains will come from. I was told not to make the exhaust side any bigger, just make it smooth. The intake side has a part in between the two ports that can be shaped to more of a point. also on the intake side. don't do anything to the port floor, and take a little out of the top. when I did mine I had to go from a 40 pilot to a 42 and a 165dj to a 170 dj, and in the winter it was a little on the lean side.

[hondaguy20]

correct me if i'm wrong but, i think on the intake port you want to keep it a bit rough. The reason i have heard to keep the port that way is that the fuel and air mix better because the mixture bounces off of the walls meaning a more even mixture. but on the exhaust side polish that pig to a shine.

[jcs003]

Originally posted by hondaguy20
correct me if i'm wrong but, i think on the intake port you want to keep it a bit rough. The reason i have heard to keep the port that way is that the fuel and air mix better because the mixture bounces off of the walls meaning a more even mixture. but on the exhaust side polish that pig to a shine.

you do want it a different texture than the exhaust side. it should be done to promote atomization without creating too much turbelance. the exhaust side should be like a mirror, if possible.

i would recommend getting the port work done by a shop with a flow-bench and knowledge of the machine. the best shop in my area is, "four stroke tech," they use a flow-bench.

you could get the extra heads done and sell them to guys for exchanges.