Just wanted to share....a little head porting

[kfxguy]

Well I'm porting a head for a friend, along with putting new valves in, some cams and a few other goodies. I figured I'd share a little bit of DIY head porting. Here's the chamber I did today and pics are in order of how it's done.

First you start by flattening the edges by the seats

More radius

Rounding it out a little more.

Dremel is used for all the above small work. Below I'm using air die grinder and cartridge rolls

Flap wheel and more cartridge rolls on this stage

It's getting there......

Crossbuff time. Coarse one ......

Fine cross buff ......

And finally polishing....using a mothers powerball and mothers polish. I usually use a cotton polish wheel..... But it disappeared. Powerball worked great.

Here's the tools I used. Pretty simple....


Tomorrow I'm going to do a light port job. I'll post pics afterwards

[biggiej42]

looks fantastic

[Felker2007]

Turned out well, what kinds of gains do you notice by doing the above?

[kfxguy]

Originally Posted by Felker2007

Turned out well, what kinds of gains do you notice by doing the above?

Well I've never dynoed a bike after. But, I've done just a port job to my bike with no other changes and it was a good noticeable difference. I've also learned a few things since then too. I think the chamber work makes the most difference because the ports in the z400 stock are pretty decent. I do a pretty good amount to the exhaust port tho. The intake port doesn't require much. I'm going to finish the head up later today and post it up. I wont be doing a full on job because we agreed on a little cleanup job. I sometimes get carried away tho. I hate doing things halfass. I've also had quite a few people tell me that their bike run a bunch better too.

Anyway, notice how much I unshrouded the valves? All the way to the head gasket inner edge. I think that plays a big role in it. Also with everything being so smooth, it helps to prevent detonation in high compression engines. I'll detail his piston too. I'll post pics of that too if you guys wanna see it.

[kfxguy]

Btw, these pics were taken with the iPhone 4s

[TuckerHardRide]

Originally Posted by kfxguy

Btw, these pics were taken with the iPhone 4s

Great job on the write up can't wait to see some specs on how well it does!
Also I ordered my iPhone 4s I should be getting it next weekend!

[Dangerouspower]

The iphone with siri will be a big hit !
If you don't mind me asking how much are you gonna ask for what your doing there including the piston ? This winter if your interested I may send you my head and piston to port and polish.

[kfxguy]

Update

Here's the beginning of the exhaust port....it's what I like to call removing the carbon so I can see what I'm working with

Here's where I'm starting to shape it

Little more.....keep in mind this is a mild port job. I'm not spending as much time shaping guides and a few other things. He's getting a better port job than I originally agreed to tho



More to come shortly......

[kfxguy]

Here's some intake work.....I like to radius the inlet....dunno how much it helps, it makes me feel better to do it lol

Above it just one side started. Below we are getting closer to the shape I want

Starting some bowl work

Little more.....

A look down the intake port, really you don't need to do much to the intake, especially on a 400cc motor. I did a slight cleanup (looks better in pics too lol!)

Little exhaust cleanup. The short turn radius on intake and exhaust need to be reshaped a little. You round it out a bit instead of the slightly square shape

[atv4life95]

Originally Posted by Dangerouspower

The iphone with siri will be a big hit !
If you don't mind me asking how much are you gonna ask for what your doing there including the piston ? This winter if your interested I may send you my head and piston to port and polish.

I too may be interested in having this done to my head over the winter..

[kfxguy]

Next the valves need to be lapped in. I know some of you guys think it's not ok to lap them in.....well I never had a problem. I've done this on every head I've done. I use a fine compound. You want a small ring undisturbed around the valve and valve seat. The grey ring should be in the middle or slightly toward the outer edge of the machined surface of the valve

And here's a comparison between a lapped in valve and an untouched valve. Notice the grey ring? Make sure you inspect the seats for pitting.


One of the intake seats was barely pitted. Well it's really not worth a valve job just yet. I lapped it in a little more and after it runs for a bit, itll deal perfectly because of the carbon buildup. If its bad, get a valve job.
You may be able to see it in the pic below

[kfxguy]

Now it's time to assemble it. I cleaned it up and it's ready for valves. I'm using drz400 double valve springs and new stem seals of course. The stock valve spring seat, retainers and locks work perfectly with the double springs. You can of course go a couple steps farther and put some kibble white springs with titanium retainers (which are heavier than the aluminum retainers believe it or not).


O and look.....the part number for the springs....

[atv4life95]

I'm not sure if this is true or not, but I heard that when you install stiffer springs, it actually hurts performance because it takes more energy from the engine to push them down, making the engine less efficient. I know that you guys all use the stiffer springs so you can raise the rev limit, but I would not see an advantage to installing stiffer springs just for the hell of it. I would think that you would want to run the softest springs you possibly could that wouldn't allow valve float.

[kfxguy]

And here's the finished product

[atv4life95]

Originally Posted by kfxguy

And here's the finished product

You really did a beautiful job.. How much would it cost for me to send my head to you to have a job like this done?