Ported head

[Diedrich]

does anyone have a picture of a ported head? what exactly is done when they do this? thanks

[UglyMotha™]

it's where they take out ruff edges and pretty much taking out excess material to give the air a more straighter path to follow

Good luck getting any usefull info on porting. :grr:

I had tried for months and pretty much gave up. :mad:

One bit of advice is to make sure you keep the VOLUME the same from left to right and do not make the intake fully polished so you keep some turbulance.

[Diedrich]

how do u polish it? i got a pretty good idea on how to port it now

[UglyMotha™]

with a very fine sanding drum on a air grinder, uh if i was you i would try to tackle this cause if you don't port it right you can actually decrease the power of your machine and another tip you only want to polish the exhaust side and acutually rough up the intake side if you polish the intake side to smooth fuel will condense on the walls and again you will decrease you power, ya really gotta know what your doin if you want to tackle this

[SandTrix]

we do a ton of 400EX heads. not really trying to advertise. but we only charge $150 and the gains are pretty significant. i think anyone that has put a cam and piston in their bike should surely consider getting the head flowed.

Originally posted by SandTrix
we do a ton of 400EX heads. not really trying to advertise. but we only charge $150 and the gains are pretty significant. i think anyone that has put a cam and piston in their bike should surely consider getting the head flowed.


Thats a good price but didnt really help this guy much :rolleyes: :D

I am thinking posting what you do when porting would better fit the thread, so let us know where your taking away the material and approx how much and about what cc's each runner is when completed :)

OK

[Diedrich]

yeah thats what i wanna know..somebody help me out..send me a picture or one ported and one thats not if ya can..thanks

[SandTrix]

porting is one of those things you could never tell someone how to do. if it is done correctly you will see a very nice increase in power, if not you will be likely to lost a great deal of bottom end power. i would recommend sending the head off to someone that has had experience in porting the heads. if not im willing to bet that you will regret it.

[L.Vegas400]

i found a web site about porting and polishing once when i was thinking of tackling the project. after reading how much math and measurments actually go into a correctly ported head i decided to leave it to the pros. i know a guy that does it, so what i started doing is helping them out at their shop a couple times a month, in hopes of calling in a favor some day:cool:

Originally posted by SandTrix
porting is one of those things you could never tell someone how to do. if it is done correctly you will see a very nice increase in power, if not you will be likely to lost a great deal of bottom end power. i would recommend sending the head off to someone that has had experience in porting the heads. if not im willing to bet that you will regret it.

Diffilcult yes but its not brain surgery either.

If you dont attempt to change the shape of the intake runners, and just open it up slightly and remove the castings marks etc you will see an improvement with little to no chance of losses. Now if you are going to try to attempt to reshape the intake runners to affect the way the fuel charge enters the valves etc you can get into trouble.

On the exhaust end its a little less complicated and most all you would need to think about as a first time porter is to match up to the exhaust gaskets or pipe id and remove the casting marks and then just polish it up. This will help a lot and there less chance of screwing things up.

I have been suprised by the amount of so called professionals that basicly just do a "clean up" porting as described above then call it a full port and polish.

With the info I had managed to get from one or two people I had decided to attempt some of the more intricate re shaping that supposedly this engine really likes and otherwise just did a clean up and I am completely satisfied since its now very very obvious that the stk carb is a bottleneck and cant flow enough for the engine, so I guess I got lucky or talked to the right people.

dont think that because I had sucess that there isnt room for trouble and I did a fair amount of match porting on chevy engines in the past so I had some experience with the basics.

Good luck.

[honda250xrider]

this is what your head will look like if you get it ported and polished

[honda250xrider]

..

Mine wasnt half that blurred :)

[dariusld]

The second picture doesn't look like they matched up the intake with the port. It looks like they need to take more material out or is it the bad picture.

[honda250xrider]

its just a bad picture i will have to get the engine out in the sun light a little bit so you can see the ports better, right now you cant really tell, i will also get you a snap shot of a stock head

[Smoker]

Do a search, there have been some good posts about this in the past for do-it-yourself porting, as long as you us a little sense you will have performance gains, also don't forget that you don't want to weaken the valve seat or guide since they take a constant beating. I talked to Terry at Marcums when I did the 400 and he advised me to open the intake 2mm and exhaust 3mm, hope that helps. :p

[oregonrider89]

I don't have much experience with head porting, but from what I've heard and what everybody can read on this thread if its done wrong it decreases power. My advice would be have someone else do it for you.

I had SandTrix do mine and I'd recommend that to anyone. It was inexpensive, good turn-around time and I noticed a significant increase in power with my stroker.

oregonrider89

[TRX_Thumper]

here is the absolute best website on the net for intake porting..most of you guys will prolly read once sentence of it then 4get about it and says it junk...well i advise you guys to read all of this website if you want a good power curve on your 400ex's...on one page it actually has some info on the 400ex...it also has lots of info on break in...i have done this guys break is procedure its true

intake porting (http://mototuneusa.com/think_fast_intake_porting.htm)

[phatswinn]

who would have thought smaller intake ports would make such a difference?, the only thing i see missing about his theory is that on the dino graph he should have shown numbers from after it gets ported (bigger)

but the idea actually sounds 100% logical, that guy is a genius and should be working for a huge company for a ton of money

[dj416]

this is tru. chack out these flow results on 2bbl and 4bbl 351 cleveland heads, the much smaller 2bbl heads make more power:eek:

flow data on small port 2 bbl heads

[dj416]

dyno results with small port 2bbl heads

[dj416]

large port 4bbl heads. (note: they flow much better acording to the flow bench compaired to the 2bbl heads)

[dj416]

forgt the pic, here is the 4bbl head info

[dj416]

here is the dyno results with 4bbl heads. see. LESS power with a better flowing head. everything on the motor is i dentical (i did this on desktop dyno on the computer, not actual dyno runs so there is not any other varible, just shows that more is not better)

[Ryan]

So from this information.... Wouldn't you get more power out of keeping your ports stock then modifying them (Making them larger?)

Now this is getting both complicated and interesting.

Every engine set up will have a "sweet spot" and this will change with every engine and mod etc, but there is also a point when there can be too much flow.

I am not the right person to explain this properly but I try to understand the potential for too much intake the same as too much flow in the exhaust. It needs so much back pressure to perform properly unless its set up (intake valving compression and timing etc) to need less restriction. The same can be applied to the intake in that it can potentially out flow the engine itself (more than the valves and cyl and exh can handle) and cause a loss of power.

Just a thought but I think the bulk of "bad" port jobs or potential power loss from them are more of a problem with 2 strokes due to the intricate method of port timming etc.

I remember more than one friend bragging about the large holly carb he just purchased for his car only to be dissapointed that it was slower after it was installed. Too much is not any better than too little unless your counting your $$$$$.

[JOEX]

This is how I look at motor work...

You can add just a cam and get some improvement...
You can add just a high comp piston and get somre improvement....
You can put in a bigger carb and get some improvement...
You can add an exhaust system and get some improvement...
You can do some port work and get some improvement....

Do two or three of these things together and have them compliment each other and you'll have a great motor.

Do everything and have each procedure compliment the others and you'll have a screaming motor.

Adding individual parts may make the motor more powerful but matching parts to compliment each other is what will make a real difference.

Joe

[Diedrich]

yeah..u need mods that work together good..try things out on your quad until u find what does the best..every quad is different..whos does the best porting? and how much will it usually run?

Good points but where that guy was going is that in many engines less porting is better due to increased port velocity. I have heard about this before and in theory it makes perfect sense and especially in a normally aspirated engine.

Now throw a turbo or supercharger etc into the mix and you can controll pressures and velocities and its a whole new game.

Its allmost a science for sure.


whos does the best porting? and how much will it usually run? I am not sure who is the "best" but the more expensive guys charge 400.00-500.00 and I have heard of smaller local shops charging from 150.00 up. I am sure the lower priced jobs are more of a clean up porting but if you believe the guy on the link above that may be better.

[Ryan]

Im guessing with smaller ports, you have less back pressure?

[dariusld]

Im guessing with smaller ports, you have less back pressure? Wouldn't smaller ports make more back pressure and higher velocity?

[cals400ex]

trx thumper, that is an excellent site.