Honda ATV Forum banner

Porting my Head

17768 Views 161 Replies 11 Participants Last post by  TRX2fiveO
Ok guys I have an extra head for my quad actually everything but the crank to build another engine. I took the head to the shop today and bead blasted all the funk off it it looks like a new head now. I taped up the top and bottom faces so the beading wouldn't pit them.
I will be porting the head next week sometime, after I finish my homework first, I'm carrying it to a local machine shop to have it Flow tested stock so I'll know where I'm at on factory CFM specs. Then it's off to the workbench and die-grinder dremel. I have done old V-8 heads so this one should be fairly simple. there is alot of casting defects to remove on the intake side and where the intake mates to the head I can see about 1.5 to 2 mm of the head so port matching that will be first. the exhaust side is pretty much the same way but I'm only going to drum sand the port and opening to clean it and reshape the exit to match the copper exhaust bushing. I will post up some progress pics as soon as I start.
1 - 20 of 162 Posts
Alrighty here are a few Before pics. I didn't take a picture of the whole head since I'm sure everyone knows what they look like and I won't be doing anything to that just yet (heat painting)
Notice the dark shaded area this is the only airflow this head has.

This is the Exhaust port notice the head protruding above the gasket face and the casting line

This is the intake opening the port split in the center will be rounded over and opened up on the bottom and top
See less See more
Right now I think I can get about 90 so with the mod I think I may hit 101 lol jk realistically I'm at about 60 to 62mph if I let my neighbor ride it lol he's a bit lighter than I think with the porting I may get another 5 to 8.
Yeah but I gotta keep up with 300ex's lol
Especially Green and Black ones..
But I got to say if I spent another 320 buck I can get a stroker crank from Poweroll that will bump me up to 350cc with a 78mm piston 11:1 cpr. then I would say look out 400EX's!!! LOL!!!
Yeah it would but for now I'm going to stick to the port job and see what my gains will be. I'm definitely replacing the valve seals valves and stiffer springs. If I got to the +1 valves I'll have to let the machine shop handle that and while they have it I may get an axis grind on them too.
I need to find somewhere around here that can do it. I don't know if a auto Chassis Dyno will work but Im game. If it will I want to do a before and after. just to compare the difference.
My buddy told me today that there was a guy here in town that had a motorcycle/ATV Dyno that I may be aboe to get a few pulls on for about 40 bucks. I'm going to find out tomorrow if he still has it.
Oh I will definitely do that if I can get it done and they print out the results I will post the sheet too.

Get some pics .
Well I started porting this morning I got to work early since this is the only time I have to do anything. So far it's turning out really well I have one intake bowl opened a little more rounded and smoothed the area around the valve guide with a smooth transition from the throat to the bowl. The first picture shows what it looked like well now there is no step lip to the valve guide and the bowl sides have a nice roll down into the intake throat. i have removed some of the edge in the third picture opening up the mouth some. More to come and pictures too!!
me no have camera

Me no see pictures!?!?!?!
Believe me if I could afford that right now I would but Ho-Ho's coming

Damn, Hey you should have wore a Go pro on your head while doing it... then we could all watch!
LMAO yeah but I would pick the wrong one knowing my luck and it would stilll be expensive. lol.... I got 4 kids to buy for so I'll have to wait on the helmet cam. they come first. ya'll understand
My wife and I do not buy eachother any gifts for X-mas the tree is filled underneath with just the kids things. and as they get older the gifts move
I will post some progress pics up this evening, i will take my head back home and grab the wife's camera.
ok I took this with my phone so the detal sucks a little. The upper left valve bowl is 90% completed I have to smooth out a few rough areas I started the right upper 50% i'd say. I also sanded the combustion area and did a quick polist to see where my imperfections are. I will try to take some beter pics tomorrow.

See less See more
I have to order a long shaft burr bit i can't reach the center of the runners too well other than that it's coming along nicely, I'm going through sanding drums like crazy!! lol. I knock off the cast defects with a burr bit and smooth with a drum so far so good, I got the bowls shaped really nice they actually look like a bowl now and not like a half-bowl.
Im using both right now
Well I pretty much have done all I am going to do in the combustion area it's pretty slick and shiny my camera phoe dosen't do it any justice.
See less See more
Gee Thanks it was my first
1 - 20 of 162 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.