Head Porting/polishing

[blankenship]

Hey do you guys think that u could do you own porting and polishing is it possible or will u just make a huge mess of your head in a hurry?

[dariusld]

Read this thread (http://www.exriders.com/vbb/showthread.php?s=&threadid=374270)

[blankenship]

you wouldnt happen to have pictures of your port/polish job would u i am pretty good with a dremel (rotary tool) i just dont want to fack up my head will removing casting flaws in the ports and anf port matching with the gasket and intake boot but will this/could this fack my head

[dariusld]

No a mild port job won't mess up your head. Just don't go crazy with hogging out your ports. Its kinda of hard with a dremel to mess up because they don't remove alot of material compared to a high speed device. If your smart and I say "go for it", then it should be OK, but if your idiot and I say "go for it" , then "facked up head" A mild port isn't going to get the gains the pros will get from your head, but it won't get messed up either.

[blankenship]

thank i think i might try it when i get some time im not lookin for a whole lot of gain just to inprove throttle response u think a mild port like this would help throttle response

[dariusld]

You have a perfect combo for port & polish. I know it will help your top end not so much throttle response.

[drillteamleader]

I have done a little port work and have researched it quite a bit. With my 400 head what I did mainly was smooth out the casting and join the 2 porteswith a sharper edge. As you look into the port, try to join the 2 ports without making the port too much wider. I was told not to make the exhaust port any bigger, just smooth it out. To make the most power you need the smallest port you can get that will flow what you need. This raises the volumetric efficiency of the motor. A small port that flowes the same as a big port will make a lot more power. The best thing you can do to improve flow in any production head is to have a three angl valve job done, the valve area has more restriction than any other area in the port.

[blankenship]

Originally posted by drillteamleader
I have done a little port work and have researched it quite a bit. With my 400 head what I did mainly was smooth out the casting and join the 2 porteswith a sharper edge. As you look into the port, try to join the 2 ports without making the port too much wider. I was told not to make the exhaust port any bigger, just smooth it out. To make the most power you need the smallest port you can get that will flow what you need. This raises the volumetric efficiency of the motor. A small port that flowes the same as a big port will make a lot more power. The best thing you can do to improve flow in any production head is to have a three angl valve job done, the valve area has more restriction than any other area in the port.


thanks for the input would you be able to give me a little more detail if i were to give you some pictures of a head that has been ported it on another head thats on this forum i would really like more info before doing this mod but i definrtly want to do this in the near future

[drillteamleader]

Like I was saying mainly just smooth out the casting, then If you look at the pics on the other thread about this you can see how the 2 ports join together in the middle. That is what you need to do. As far as the valve area, If youre not getting a valve job, take out the valves and smooth out the transition where the port turns down to go through the valve seat. There was Quite a bit of a lip on my head. Make sure you don't nick the valve seat at all, or you will need a valve job anyway. When done properly, and that is not possible without the valve job, if you cut the port down the middle to see a side veiw, It should look like a ventoury.

[drillteamleader]

Also, do as little as you can to the bottom of the port to get it smoothed out. From the research that I have done the bottom of the port is a stagnent area, if you grind it all down then you just made it bigger and didn't improve the flow much, if any at all. Once you have all the casting smoothed out go over the top of the port and take just a little bit more off closer to where it turns down to go throught the valve. If you where looking through the port, the turn from the floor of the port down through the valve shouldn't be diturbed unless you know what you are doing.

yeah thats the hard part about it is the bend int he ports its so hard to get the tools in there. I messed around with the damaged 400ex in my garage I took a drill and a wire brush bit that fit perfectly in the ports it had some tension to take material off. It cleaned them out really well and smoothed them down a little bit but nothing major. Thought about doing it to my own but it isnt worth it for me to take apart my motor and valves and all for 1 or 2HP. A dremel you have to make sure you dont dig in and make it uneven. I might practice more with the dremel on the dmaged head though. Thats what I recomend, go find a used head thats cheap maybe its got chunks out of it but the ports are fine. Even if its a car head you get at the junkyard and mess around with that before you do work on something that will actually be running. Might sound like a waste of time but you will learn how to do it and if you mess up its no big deal.