how do I calculate shim size needed?

But just subtracting one shim size and adding a shim size ain't to hard to figure out either.

KZB2 650 wrote: But just subtracting one shim size and adding a shim size ain't to hard to figure out either.

RIGHT!!!
And after this, that is the way you'll do it from now on.
It's what I do, unless the head has fresh valves or valve grind.

Earlier on I said I've never had to buy or move shims that were more then one or two sizes different then how it was set up from the factory.
Normally, you'd see the gaps in there close in.... closer to the small gap range allowed by the FSM.... when they get too close, you just buy the next smaller number shim and install it. Then put the cams, chain and cover back on and go ride the mofo!
You have one that looks like it need one size bigger.... intake #3.... it could use a #255. That going larger is odd....

Unless a valve has been nicked. Sometimes you can switch shims around, buy a couple, save the old ones and use them later.
Steve

I think I have the valve shims I need figured out. I'm going by the equation they gave me in my manual.

Got this so far. Looks pretty good.

missionkz wrote:

KZB2 650 wrote: But just subtracting one shim size and adding a shim size ain't to hard to figure out either.

RIGHT!!!
And after this, that is the way you'll do it from now on.
It's what I do, unless the head has fresh valves or valve grind.

Earlier on I said I've never had to buy or move shims that were more then one or two sizes different then how it was set up from the factory.
Normally, you'd see the gaps in there close in.... closer to the small gap range allowed by the FSM.... when they get too close, you just buy the next smaller number shim and install it. Then put the cams, chain and cover back on and go ride the mofo!
You have one that looks like it need one size bigger.... intake #3.... it could use a #255. That going larger is odd....

Yeah I didn't get why that one was too big

Blink, here's a link to the KZ650B1 Factory Service Manual.
I believe your '78 (B2?) will have some minor changes, like headlight switch and brake caliper position.

www.dropbox.com/s/ielbey7s4nwqc96/Z650%2...Service%20Manual.pdf

from here: www.zedrider.co.uk/service--owners-manuals.html

blink543 wrote:

Got this so far. Looks pretty good.

Can anyone comment on this?

Since you asked -

You only need to change 2 shims. The other 6 clearances are well within spec. The spec is .08mm - .18mm. If your Clymer book says the clearance must be .15mm it is bogus; no credible specification source would ever give a single measurement for valve clearances. There is ALWAYS a range, and in this case the range is .08mm - .18mm.

None of this information is likely to change your mind since you seem hellbent on changing more shims than should be changed and setting the clearances on the outside edge of the range instead of leaving them near the most desirable settings. But that's ok. It's your bike, so do what you like. Ed

Yup.
Steve

650ed wrote: Since you asked -

You only need to change 2 shims. The other 6 clearances are well within spec. The spec is .08mm - .18mm. If your Clymer book says the clearance must be .15mm it is bogus; no credible specification source would ever give a single measurement for valve clearances. There is ALWAYS a range, and in this case the range is .08mm - .18mm.

None of this information is likely to change your mind since you seem hellbent on changing more shims than should be changed and setting the clearances on the outside edge of the range instead of leaving them near the most desirable settings. But that's ok. It's your bike, so do what you like. Ed

Ok? Well if I shim a valve that's at .10 to open it up one size who cares? It's still in spec is it not?

Yes, and if you change the shim from 2.60 to 2.55 on a valve that currently has a clearance of .127mm (as you show for intake #1) you change the gap to .177mm, and theoretically that is also still within the .08 - .18 spec but only by .003mm rather than being close to the center of the range as it currently is set. That, of course, assumes you can actually measure accurately to 3/1000 of a mm which I know for a fact you and I cannot do with feeler gauges.

As I said, it's your bike and your engine so do want you want to it. I'm sure you know more about it than me. I've only owned and maintained my KZ650 for 38 years and 58,000 miles, so what would I know about it? Then again, my bike still runs quite well. Ed