Porting and polishing

[400EXIAN]

I am hearing good thing about a good port and polishing...Is this a big power gainer? Can i do this at home (I would assume it shouldnt be hard with the right tools)? Would it be worth my time or is it better to have it done? Anyone who has done their own do you have any directions, good tips, or templates?? My bike as of now has a 155 main jet, a big gun slip on, and a K&N filter. Would a port and polish help me any???
Any info is very very much appreciated!!
-Ian:D

[dariusld]

I did my own port and polish. When I took the engine apart to put in a new piston and cam,I figured what the hell. I thought if I don't go to wild, I won't hurt anything. First thing I did was to smooth out the casting flaws. On the intake and exhaust ports, there is a line going down the sides, I ground those down smoooth with the rest of the port. I was a little more aggressive with the exhaust ports than the intake. On both I tried to grind the spots that didn't give me a straight shot into the cylinder. I wanted a straight line in, as much as possiable.You want to match the port side with the exhaust manifold or intake manifold. If you go bigger than that, you will get a leak. On the exhaust side I just etched inside the exhaust gasket, took the old gaskets off and grinded down to those marks. They say you should go about an inch in. On the intake side I just started grinding down any humps in the port. Then I put the intake manifold on to see if it was a smooth transition, from manifold to the port. I did this a couple times before it was a smooth entry. The final steps was to polish the exhaust side. I didn't spend alot of time here. I didn't polish the intake at all. They say you shouldn't. I don't know if my port and polish made a differrence, positive or negative, but it was free. I love free. I'm not saying this is what you should do, I'm just telling you what I did. I don't think a port polish will help as much, if you don't have a cam.

[Steve-o 400EX]

I wouldnt recommend getting a port and polish done unless you get a new cam, piston, springs and valves. You wont see a very big difference without this stuff done. I wouldnt do it yourself, I would send it out so you know it was done right, if it is not you could screw up your head. I would invest in motor mods like a piston and cam before that. I am getting mine done later on this summer, I already have an 11:1 416 kit and a hotcams stage 2 and they made a huge difference.:macho

its your money, you would benifit from other things first....but if you do port it yourself...take your head somewhere and have them sandblast inside the INTAKE ports only...its to help keep fuel build up down or something i dont know...but get the outside as smooth as mossible(send it to me and ill polish it!) j/k