how do I calculate shim size needed?

650ed wrote: 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

Oh I didn't know it changes the gap that drastically.

It's best to me in the middle range. Like I said, it can be good for 3-400 miles.
Steve

650ed wrote: 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

Would it be ok to change the #1 exhaust from a 2.65 to a 2.55?

It certainly is not what I would do if it was my bike.

Your drawing shows that the current #1 exhaust valve clearance is 0.076mm, and you state the current shim for that valve is 2.65.

Kawasaki specifies the proper clearance range as 0.08mm – 0.18mm.

Assuming you are correct about the current 0.076mm measurement and the current 2.65 shim size, if you replace the current 2.65mm shim with your suggested 2.55mm shim your shim will be 0.10mm thinner than the current shim. Given that, you will be adding 0.10 clearance to the existing 0.076mm clearance. That is 0.076mm PLUS 0.10mm. When you add those together you get 0.176mm. That is right at the maximum end of the 0.08mm – 0.18mm range. So, why would you want to do that rather than try to set the gap toward the middle of the range?

If that was my bike and I wanted to adjust the clearance (again, assuming you are correct about the current clearance measurement and current shim size) I would use a shim that would get the clearance closer to the center of the specified range. In this case, if the current clearance is 0.076mm and the current shim size is 2.65, I would use a 2.60mm shim. This would add .05mm to the current clearance which would make the new clearance 0.126mm. That is extremely close to the middle of the 0.08mm – 0.18mm range which is 0.13mm.
Ed

Jethro Tull

Your current clearance. What I recommended # (Eds after 42,000 miles)

Exhaust
#1 .003...265 shim #260 shim ........005 ( .006)
#2 .004...275 shim #270 shim..........006 (.007)
#3 .005...280 shim 280 shim...........005 ( .006)
#4 .004...275 shim #270 shim...........006 (.005)

Intake
#1 .005...260 shim 260 shim..........005 (.006)
#2 .004...260 shim #255 shim...........006 ( .0045)
#3 .008...250 shim # 255 shim..........006 (.005)
#4....005...250 shim 250 shim..........005 ( .005)

# are the 5 shims I recommended you change and I used your thousands figures off the valve adjustment thread you started when you first asked about this.

Just wanted to add Ed is totatly right when he says the 3 I recommend opening up from .004 to .006 are in spec but they are so close and since you have the cams out anyway it could save you from pulling them again in 4 to 8,000 miles.

"Jethro Tull"

:laugh: :laugh: :laugh: :laugh:

650ed wrote: It certainly is not what I would do if it was my bike.

Your drawing shows that the current #1 exhaust valve clearance is 0.076mm, and you state the current shim for that valve is 2.65.

Kawasaki specifies the proper clearance range as 0.08mm – 0.18mm.



Assuming you are correct about the current 0.076mm measurement and the current 2.65 shim size, if you replace the current 2.65mm shim with your suggested 2.55mm shim your shim will be 0.10mm thinner than the current shim. Given that, you will be adding 0.10 clearance to the existing 0.076mm clearance. That is 0.076mm PLUS 0.10mm. When you add those together you get 0.176mm. That is right at the maximum end of the 0.08mm – 0.18mm range. So, why would you want to do that rather than try to set the gap toward the middle of the range?

If that was my bike and I wanted to adjust the clearance (again, assuming you are correct about the current clearance measurement and current shim size) I would use a shim that would get the clearance closer to the center of the specified range. In this case, if the current clearance is 0.076mm and the current shim size is 2.65, I would use a 2.60mm shim. This would add .05mm to the current clearance which would make the new clearance 0.126mm. That is extremely close to the middle of the 0.08mm – 0.18mm range which is 0.13mm.
Ed

Shit well I already ordered shims. All the sizes I don't need

Are you even reading what I'm saying or don't you trust me? All you need is 2 -#255s and 2 - #270s ..... the #260 for the #2 Intake you will have left over (by replacing it with the #255) you can use for the #1 exhaust.

I was getting at that two pages ago.
Steve