porting and polishing heads.

[Mojoe]

It is a well known common fact that if you port and polish your heads, you will gain significant performance. In case you do not know the basics behind it, it is just to smooth up the casting of the head and mainfolds to allow for smoother air flow.
I have all the stuff to do mine on my old engine that I will rebuild with a few mods.
Anyway, if you want a good read on the basic and the "how-to", here is a decent site. Anyone can do it and the gains are worth it. A shop will soak you $4-500 for doing it.

So I have a question for you all. If you could swap your head and $100-$150 for a polished and ported head, would you?

http://www.sa-motorsports.com/diyport.shtm

[ThAzKat]

Good link, yes I would if I had insurance that the work is kickarse. Is that something you are considering. I would like to actually have both a stock head and a mod head.

[Mojoe]

I am not a stranger to polishing and porting. I did alot when I was racing cars back years ago...amateur stock car on dirt track. As it says in the article, you can do both heads on a v8 in about 8-10 hours, but more like 5 or 6 after you have done a few. I have not done a bike yet, but see no difference. I will do mine first for sure and let you know how it turns out. Is it something I am considering doing? Yes. Once I get my shop all set up (grr...been a year waiting), I plan on doing all kinds of stuff. Not any one thing in particular all the time because I get bored quickly. But if I can pick up an old engine and make an extra $100-$150 bucks by porting the head and say sticking it on ebay as a core exchange auction, sure...why not. Should not take more than 2 hours to do a bike. I already have all the tools for it...and a zillion other things. Basically I am just taking on enough work to cover my cost to do my own stuff on my own bikes. I kinda wanna take older tired bikes and ressurect them. So every once in a while when I get an idea about something to make a few bucks, I ask questions like this to see who would be in the market.
I know a guy who had his head done last summer on a v-twin harley and it cost him over $400.00 And that is walking into the shop with the heads in hand. As you can see by the article. it is really easy to do...any of you can do it yourselves.

[md86]

Re: porting and polishing heads.

So I have a question for you all. If you could swap your head and $100-$150 for a polished and ported head, would you?

http://www.sa-motorsports.com/diyport.shtm

You know , I was thinking about that same thing just the other day ! I wouldn't feel comfortable doing it myself . Hell , I don't know if I could even get the HEAD off myself !

[ThAzKat]

Awesome Mojoe, I am interested in seeing the difference between stock Kat head and port and polished on a Dyno. I am sure because of the better flow there will be other things that need to be done.

I hope there is alot more interest!!!!

[Mojoe]

You know , I was thinking about that same thing just the other day ! I wouldn't feel comfortable doing it myself . Hell , I don't know if I could even get the HEAD off myself !

What engine would this be for? I will be tearing down my spare 1100 oil cooled soon and doing it. I am also going to polish up the side covers and stuff....just for some practice. I will post pics when done. If you have an 1100 oil cooled engine, then I will do a swap with you for the parts.

[The CyberPoet]

I wouldn't bother with a 98+ engine (just how much power could I free up?); porting the exhaust header's sloppy weld seams right at the start of the pipes takes far less time and usually benefits more. But that's just me...

Cheers
=-= The CyberPoet

[tzortn]

I wouldn't bother with a 98+ engine (just how much power could I free up?); porting the exhaust header's sloppy weld seams right at the start of the pipes takes far less time and usually benefits more. But that's just me...

Cheers
=-= The CyberPoet

Keep in mind that porting can increase the engine HP, but it can also help we the engine's responsiveness. You may not be looking for more power but being able to more quickly and easily tap into the power that you do have is a good thing.

[md86]

You know , I was thinking about that same thing just the other day ! I wouldn't feel comfortable doing it myself . Hell , I don't know if I could even get the HEAD off myself !

What engine would this be for? I will be tearing down my spare 1100 oil cooled soon and doing it. I am also going to polish up the side covers and stuff....just for some practice. I will post pics when done. If you have an 1100 oil cooled engine, then I will do a swap with you for the parts.

771 , actaully . Seems like more of a pipe-dream at this point than anything . SOUNDED pretty cool !

[Mojoe]

771 , actaully . Seems like more of a pipe-dream at this point than anything . SOUNDED pretty cool

Why a pipe dream? Porting and polish is VERY easy to do. One of the simplest things you can do to to gain significant performance. The hardest part about is head removal/installation. If you can do that on your own, the rest is cake.

[BlackB12]

Yes, in theory it's not terribly difficult to port your own heads. Howover porting only may not yield any gain at all on a stock bike. In order to flow more, you'd also have to have a more aggressive cam in there. To get the higher lift cam to work best, you'd need more compression. Maybe slot the cam sprockets to allow custom phasing of the cams.. So now you have a head porting, cams, and piston kit. THEN you'd see some gains. Also, with home porting, how would you know that each cylinder flowed the same without a flow bench? You'd most likely end up with 4 different rates of flow making jetting the bike quite a challenge.

Mike

[tzortn]

Yes, in theory it's not terribly difficult to port your own heads. Howover porting only may not yield any gain at all on a stock bike. In order to flow more, you'd also have to have a more aggressive cam in there. To get the higher lift cam to work best, you'd need more compression. Maybe slot the cam sprockets to allow custom phasing of the cams.. So now you have a head porting, cams, and piston kit. THEN you'd see some gains. Also, with home porting, how would you know that each cylinder flowed the same without a flow bench? You'd most likely end up with 4 different rates of flow making jetting the bike quite a challenge.

Mike

You bring up good points. They crossed my mind, but after reading the article that Mojoe posted I was reminded that we are not talking about high end race motors. Often the castings on stock engines are so nasty that a little clean up will make a difference. As for the balance if you are not changing the port shape, just smoothing it, the balance should not be upset. We used to hand port our heads and flow them until we found something that worked. We would look into both flow velocities as well as flow patterns. The hand ported runner was then scanned so we could create machine code that was used to CNC port all of our heads.

[BlackB12]

cool. I didn't know how the cnc porting worked until now. I find that amazing that the machine can scan a 3d object and turn that into a cnc program.

Mike