Valve info

Can anyone tell me what the valve angle is on a KZ650 and also what the interference is for valve seats? By that I mean the interference between the valve seat OD and the hole you put them in. I'm gonna throw caution to the wind and do all my own machine work this fall. Also does anyone know what grade of bronze to make the seats out of?

Also what sizes are the stock intake and exhaust valves? And how big can the intake go out to?

I really dont think you want to go down this road, there is a reason as the saying goes "pay the man".
There is a lot of special equipment used in doing a valve job, you ask about material for valve seats, there is a specific hardness and press that has to be done just right or things will go way bad in addition the correct placement of the seats along with grinding them correctly to match the valve face.
I know doi it yourself is fun, but the machines and skill to use them goes a long way

I appreciate that, but if you dont know the answers to any of my questions dont post please. Why assume I dont have the knowledge and resources to do these things myself? Its a bit harder to cut the valve angles on a CNC than the real machine, but I figure the old girl's up to the job.

let me explain something, I spent 12 years as a automotive machinist, I do know the what needs to be done and the proper way to do it.
with that being said, you dont turn the valve in a lathe, you grind them on a valve grinding machine, the lathe will cause the valve to flex thus not being true.
I was trying to be nice and help you out and keep you from having a problem, with that being said, your on your own

Right on. Did I say I was putting valves in lathes?

77_650B1 wrote:

Right on. Did I say I was putting valves in lathes?

No, but you could

You could use a collet to hold the valve in the spindle, then use a tool post grinder to grind the valve.

You can also bore a cylinder block on a lathe, make a fixture to mount the block on the cross slide, then run a boring bar between centers.

Unfortunately, none of the above has anything to do with your original question

I think you're asking the wrong people, you probably should ask the people at www.practicalmachinist.com by posting in the General forum there.

I know what CNC is, and basically how it works, but I have no experience with any cnc machine, not even a cnc router


And good for you for wanting to do it yourself!!!

77_650B1, Don't take anything that follows as fact, only my opinion. You can measure the valve angle using a sine plate and a 7 mm mandrel. (the included angle is probably in the FSM) I once pursued replacing the seats on my Z1 and talked with an automotive machinist. He had store bought blanks on the shelf. He spoke of using a slight taper along with the interference fits to secure the steel inserts into the aluminum head. You can look up the Linear Expansion for both materials in the Machinists Handbook and from those numbers, figure what dimensions will keep the seats locked in the head, along with the profile of the reverse taper. I read an article on a new Ducati and they mentioned using Beryllium (SP) Copper. This material is pretty amazing and is sold though Brush Wellman. The valve diameters also should be in the FSM.
You'll probably end up making a sine fixture large enough to position the head for the mill work. My 0.02 cents worth, ride safe, Steve

77_650B1 wrote:

I appreciate that, but if you dont know the answers to any of my questions dont post please. Why assume I dont have the knowledge

Here is some knowledge you may not have: just making valves bigger does not mean you will get better flow or more HP, in fact, it may screw it up worse than it is now.

As for valve seat angles, my FSM says to use:

75 deg (top chamfer)
45 deg (main face)
30 deg (bot chamfer)

going from the outer surface of the head in.

Cool, thanks all. I've gotta get a FSM actually, all I have now is a clymer. The seat angles help a lot! I just wanna get most of this stuff planned out before I begin.

Steell, wouldn't it be easier to make a boring bar of the right diameter for boring the cylinders, and do it on a mill?

I hadn't thought about a taper, thats surely something to think about too. I've got a few engine design books here I have to look at. I'll be crunching the numbers too over the next few months to see what size valves to use with the 810cc.

(PS - I'm a mech engineering student in my 5th year university, this will be a nice project for me.)

I'm not a professional machinist, I'm a home shop hobby machinist, which means I can operate the machines in my home shop, I can use the machines to make a big ole mess, and on rare occasions, I can even make a part that bears some resemblance to the drawing I started with, and may even (on even rarer occasions) measure within .050" of what it's supposed to be.

And I've worked hard to gain those qualifications

If you have a mill with enough vertical travel to bore the cylinder, then that is easier, but if your mill doesn't have the required travel, then the lathe takes over.

I don't care if it costs me $1 and twenty hours labor to make something I can buy for $30, I'll learn something in the doing that will last me the rest of my life, and more than likely be needed again to make something else.

And besides that, it's fun

I'm exactly the same way steell!

The boring can definately be done on a milling machine. Criterion makes really nice boring heads and maybe you can borrow one. Remember the boring is only the first "roughing" operation. The idea is to get a round straight hole that can be honed for finish size and crosshatch. Sunnen makes some fantastic honing machines. Those guys can literally hold 50 millionths of an inch.
steell and 77_650B1, I sure like your attitude on the learning process. I agree that the little "pearls" of knowledge I have were at the expense of making mistakes! It seems that is the way I learn best. I've been torturing raw material into usable components for my adult life, so I have some answers on some subjects. If I can help, I'll enjoy it. Ride safe, Steve