what valves to get kz9000

I have a 76 kz900 Im going to start putting back together. the motor is all stock. I bought new bronze vavle guides and seals. I had a kz guy I know tell me what I needed but we know longer talk. So I could use some help from the experts!
Im looking to put in ape 37.5 intake and not sure what I should go on the exhaust
I emailed pitstop performance for a quote on there valve job and valves waiting to find out what thats going to run me. . I live in Indiana and dont really know anybody around here to do the work.
what size exhuast valves should I go?
not sure what carb I have its a mikuni I measured the manifold side it read 1.25 inch / 31.75mm

Being all stock I can't see you needing anything larger than stock. Just my 2 cents.
What part of Indiana?

Les

lebanon In. heres a pic of the carbs, not rally sure what they are. I was told if I go with 37.5 intake it would help it open up a little.

Carbs are around 1974 28mm.
Truth is you need to speak to a cylinder head guy and tell him your plans. Each one has their own specific ways of doing things and can explain the whys and why not of larger valves.
I live around Kingman, use to work in Thorntown back in the late 80's. Played over there a few times, they had some good running stuff.

Les

Ya you should really talk to a professional. it all depends on what you want out of the bike and how you ride it.and if you go with bigger valves you would want to port the head to make much diffrence.

your one stop shop www.cavanaughracing.com/

I talked to a guy at ape, he said it would help it breath a little better that they came restricted from the factory. I will give the link above a call tomorrow and see what the have to say also.

are them carbs I have work on my bike good?

wood9781 wrote: I talked to a guy at ape, he said it would help it breath a little better that they came restricted from the factory. I will give the link above a call tomorrow and see what the have to say also.

are them carbs I have work on my bike good?

If the bike is stock. If you're not making the motor bigger, the stock 36's are fine on the intake side. If you want new valves, Kibble White is what you want.

I prefer to use either J model 37mm or GPz11 38mm when going over size in a KZ900 / 1000 head. They're .050" shorter than the KZ aftermarket 37.5 intakes. That works big time in your favor if you have a stock 1.110" base circle cam.

I believe there was a misunderstanding when you spoke to our people. The restriction is in the seat throat. Opening the seat throat and blending it to the port will help increase flow with the stock 36 valve. All of the newer bikes like the busa comes from the factory like that.

Its all stock motor Im not goin to put a buch of money in the bike, so should i still get a valve job done with the vavle guides amd seats since i already have them? what size valves should i get for the intake and exhuast.
So the 37.5 is not worth it?

thanks for the help guys, just kinda new to the kz's

wood9781 wrote: Its all stock motor Im not goin to put a buch of money in the bike, so should i still get a valve job done with the vavle guides amd seats since i already have them? what size valves should i get for the intake and exhuast.
So the 37.5 is not worth it?

thanks for the help guys, just kinda new to the kz's

Oversize valves require sinking the seat to keep the valves from tangling. For what you're trhing to accomplish, it's not worth the cost unless you intend to add cams and a big bore kit.

If you pull it apart yourself to do the work, open up the throats to 90% of the diameter of the intake valve or 32.4mm. By throats I mean the hole in the valve seat. It has to be blended back into the bowls.

When you don that, you'll take material away from the seat and the bowl, all the way around. Don't lay the short side [port floor] back.

When you look at the exhaust valves, you'll see they're seating way low on the face. That needs to be corrected also. Push the seat out on the face toward the top of the face. Open the exhaust throats to 89% of the diameter of the exhaust valve or 26.7mm. They'll be close to that already.

Here's a picture

Thanks Larry looks like I'm staying stock