[duhast]

What's your opinion of this?

http://www.cycledoctor.com/JohnsonArticles/JET.html

 

[springer-]

What's your opinion of this?

What part of it? There is a ton of stuff there.

 

[duhast]

Well, just a general feel. Do they know what they're talking about, or blowing smoke?

No, I'm not thinking of going to them for work. My dream is still Big Boyz....

 

[springer-]

Well, just a general feel. Do they know what they're talking about, or blowing smoke?

No, I'm not thinking of going to them for work. My dream is still Big Boyz....

I have read that article before. There are a couple things that come to mind. He comes from an auto racing background and applied the same principals, sound move. Absolutely makes sense, I certainly wouldn't argue with him. But that is an old article (guessing) because it only talks about Evo's. It is pretty much common knowledge that EVO ports and valves were too big from the factory. Some of the principals that he applied to those heads can be found in the Stock Twin Cam heads. The Twin Cam heads have smaller ports yet a larger displacement engine, how could that be? Same principal. Of course the stock TC heads don't have hemi combustion chambers and still use the quench to help create turbulence and promote burn.

In speaking with Bean many times about porting and cylinder fill he has said similar things about port velocity and cylinder fill after BDC. Bean retains the stock size valves and only works on the port. The stock intake valve size helps keep the velocity up. JET welds up the ports and reshapes them to maximize this effect (based on the article). The extra work is costly.

I guess it comes down to Money and what you want out of the bike. If you want a maximized build and are shooting for a top performer and money is no object, then there are many expensive engine packages that can get you there. Bean's concept is to take what the factory gave you and make it better. Better performance at a reasonable price for those of us that want more but aren't out there to drag race or made of money.

This is just my opinion, I am not a head porter or engine builder. I have a basic understanding of the whole process and am still learning about the whole cylinder fill vs cam timing etc..