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Discussion Starter · #1 ·
helo,
i am looking for some hp by using a regrinded camshaft by Kent or Piper in my 2003 ZX9R.

anybody here, who can say: "yes, do it; it works great !" ???

PS: i am driving on race tracks, not 1/8 or 1/4 mile
 

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You can pick up some HP with them.

We used Web regrinds in the street and race engines.

I found the Web intake with the stock exhaust cam gave the best bang for the buck. When both cams were installed the midrange really fell off and the gains up top were not all that great.

THE best bang for the buck -
- Pull the head and cylinders.
- Re-ring if you want.
- Replace the wrist pins w/ pins from a ZX-7R. These are the lighter pins Kawi originally used. Kawi uses the stock pins in their race kit for Super bike.
- Toss the metal gasket that goes in between the case and the block. Assembly with sealant. This will tighten up the squish and boost compression. Better than just milling the head.
- Install block & cylinder head. Use OEM Kawi head gasket. Torque to 45 ft lbs.
- Install Web intake & stock exhaust. Set valve clearances to loosest spec.
- Time camshafts to 103 intake lobe center & 105 exhaust lobe center.
- Install 2 degree ignition advancer.

I like Denso IU31A spark plugs. They are one range colder than stock. I see Denso has an iridium race plug now, but I haven't worked on anything in a couple of years (praise be to merciful Allah) so I don't know anything about them. If you don't agree with the colder plug or iridium's then good for you, just buy whatever plug you think is great but please don't turn this guy's thread into a 10 page argument about spark plugs.

Assuming you have already installed a pipe, jet kit, & BMC race filter - re-jet as needed.

You could have the head ported while it is off. The intakes are very good, they just need some blending/matching/flash removal.

I would not recommend milling the head unless you are a very experienced builder. Once the base gasket is removed and you install the Web intake cam there is not a lot of room to play around with so you really have to know what you are doing there.

This has all been posted before.
 

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For pipes, the best I have seen for 98 and newer is Akrapovic. Fit & finish, sound, and power it is a good pipe. I have not used their Evo pipe, but the 9R engine likes tapered head pipes.

The M4 pipe works good too.

The Ti Force pipe worked best on the 98/99 bike but has a huge dip on the later models. Kawi changed the head around and you need cross over tubes to get rid of it. This is right from M4. They ran into the same issues when they tried the 98/99 pipe on the 2000 model. They fixed it by installing cross over tubes. Akrapovic uses cross over tubes on all years pipes.

If this bike was still current, I would love to see a tapered head pipe Akrapovic to see what kind of power that would make.
 

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Discussion Starter · #5 · (Edited)
Thank you. That are really nice advices !!!

What are you thinking about the inlet camshaft of the ZX900C in a ZX900F (because there ist 16° longer duration with same max lift and same lobe center)??? Could this work? i am thinking of longer valve opening and so better charging at high rpm with some losts at low rpms?

But Piper and Web use a shorter duration (even shorter then original)? perhaps to realize higher air flow speed for better charging/air-fuel-mixture? questions over questions, damned. i dont want to use the try-and-error-method (-;

(i think, this could be an endless story)
 
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