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Discussion Starter #1
hi

I cant find info im after in the uk so hope you guys can help out,
sorry if its been asked before.

ok im just in the process of stripping and rebuilding my race bike (zx10r 06)
what i need to know is when porting the head is it best to make the ports as big as poss or just stick with keeping them as they are and just matching them (size)
also if i go bigger how big?


thanks in advance
 

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you actually want to get them smaller. do a search, there are some info on this. i think garth is the one you should talk to
 

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If you are doing it yourself, keep the shape and general size, and smooth out all surfaces, including unshrouding the valves. Look at the race manual, the process is described there. Get a good valvejob, install stiffer springs, and you're good to go.
 

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Discussion Starter #7
this is why im confused , everyone in the uk tells me to stick with stock valve springs and valves.
I`v manged to get a thin head gasket so was just hoping to tidy the head up enough to get at least 180bhp
 

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Like was mentioned before, if u are doing them yourself just clean them up a bit. If u are going to have them done there are pro's out there who actually make the ports smaller to maximise velocity. I read of this on one of Garths threads (wish he was still around....). They were claiming around 10hp gain.
 

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Most pro porters (Carpenter, KWS, Lee Shierts, Lazer, Comp CNC) will open up the port volume. The reduced choke velocity port is an alternate, less common method. I picked up 8hp with mild porting, a race cam, 14:1 CR, and .026" squish. I have a small-port head now on my turbo, built by Ryan Kallina, but haven't tested it back-to-back yet. The stock valves are fine for normally aspirated motors. Swap out the Ti ex valves for turbo or heavy nitrous use, too much heat.

If you plan to use the motor at high rpm ranges, I would highly suggest a set of stiffer valve springs. Not only will the head perform better with more accurate valve closing, but you will help to prevent valve spring retainer failure. The Carpenter 62lb single springs are $150 from Schnitz Racing. The APEs are a bit lighter weight, double spring, and around the same price from APE.
 

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hi

I cant find info im after in the uk so hope you guys can help out,
sorry if its been asked before.

ok im just in the process of stripping and rebuilding my race bike (zx10r 06)
what i need to know is when porting the head is it best to make the ports as big as poss or just stick with keeping them as they are and just matching them (size)
also if i go bigger how big?


thanks in advance
If you won't need any portion of your engines powerband except the last 20%, sure make everything big...ports, cams, exhaust, etc. If you want an engine crisp and responsive yet still wiiling to rev keep port size within the stock size and shape. In the "2mm?????" thread alot of useful info is posted.
 

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Kibblewhite also makes a very very nice valve spring and retainer setup that I run in my motor. Seat pressure is less that the heavy carpenters and it can be that way because it uses a double spring. It also comes with a ti retainer and gets rid of the stock crap ones. Dwayne at Cycle Concepts is a sponsor here and can get you a good deal on them.
 

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I'm glad someone mentioned it, we wore out a few Busa heads with Carpenter springs and found out the expensive way how important a proper valve spring is.
 

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Kibblewhite makes the best springs and spring kits on the market...I'll be happy to help anybody that may have questions about the product..
 

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do not open the intakes all at, if anything make them smaller on the floor of them
 

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Most pro porters (Carpenter, KWS, Lee Shierts, Lazer, Comp CNC) will open up the port volume. The reduced choke velocity port is an alternate, less common method. I picked up 8hp with mild porting, a race cam, 14:1 CR, and .026" squish. I have a small-port head now on my turbo, built by Ryan Kallina, but haven't tested it back-to-back yet. The stock valves are fine for normally aspirated motors. Swap out the Ti ex valves for turbo or heavy nitrous use, too much heat.

If you plan to use the motor at high rpm ranges, I would highly suggest a set of stiffer valve springs. Not only will the head perform better with more accurate valve closing, but you will help to prevent valve spring retainer failure. The Carpenter 62lb single springs are $150 from Schnitz Racing. The APEs are a bit lighter weight, double spring, and around the same price from APE.
I picked up 13HP with a small ported head,kaw race intake cam { Ryan Killina}
same dyno before headwork, and after headwork picked up 13hp
 
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