Stock valve shim size?

Hogges · December 22nd, 2023, 08:40 PM

Does anyone know which valve shim size is installed from the factory I measure 2.95mm for the intake and 2.85mm at the exhaust side. The shims have no writing on them. Just want to make sure I am not ordering the next size down only to find that it’s the same or too much. It’s a bit hard to see the exact number on my mechanical caliper.
Thank you!

Mohawk · December 23rd, 2023, 05:55 AM

You need to use a micrometer to measure the shim thickness. They are all different at the factory just like you they measure the clearance & adjust to the correct gap when new. As it wears in then the gap increases or decreases, hence the need to adjust it over time.

The process to find required replacement shim is to measure the gap first for all valves & make a table of each valve gap.

Remove cams & read or measure each shim size.
Add shim size + gap per valve & then remove the required valve gap to find the new shim size required.
You may be lucky & be able to move shims around & thus not need to buy many.

Have fun.

Hogges · December 24th, 2023, 10:30 PM

Wouldn’t the advantage of shimmed valve spacing be that the manufacturer can omit the individual adjustment? How would this even work? They would need to run the engine for a bit to give the valves a chance to settle in, then take everything apart again to measure and install the proper shims? This would be very expensive. Aren’t modern manufacturing tolerances able to omit this and use the same size for all bikes coming off the line, at least for a while?

Mohawk · December 27th, 2023, 05:49 AM

I think you have a poor understanding of engine manufacturing. It is NOT 100% accurate, hence things like valve clearances have to be set for every valve. The engine does not need to run. They are set on a build bench when the head is built up as a sub assembly. Which then goes to the engine assembly line. The engine is only run once the bike is complete & gets its post assembly systems check.

Engines are run by the manufacturer on a dyno & given real world duty cycles. They're stopped & inspected after various mileages to determine the maintenance schedules for various components, like valve clearances etc.

So as previously stated every valve has an individual shim size that was correct when the head was assembled. Follow the recommended process to set your clearances correctly.

Have fun.

Hogges · December 27th, 2023, 08:09 AM

I don't know how the manufacturers go about this exactly. But my bike has all the same shims for all four valves and they only come in increments of 0.05mm anyway as per Kawasaki's service manual. Still seems reasonable to me that there is such a thing as a stock shim size in high volume engine manufacturing, eliminating the labor cost of individual screw and locknut adjustment of rocker arm designs. I'd be happy to find a video showing the assembly steps at the factory.
Anyway, shims finally shipped and I look forward to putting this mess back together soon, and hopefully without messing up the timing, kinking the timing chain or dropping any parts into the lower engine.

December 22nd, 2023, 08:40 PM	#1
Hogges ninjette.org member Name: Wolfgang Location: Vermont Join Date: Nov 2023 Motorcycle(s): R1200GS, DR200SE, Ninja EX300 Posts: 17	Stock valve shim size? Does anyone know which valve shim size is installed from the factory I measure 2.95mm for the intake and 2.85mm at the exhaust side. The shims have no writing on them. Just want to make sure I am not ordering the next size down only to find that it’s the same or too much. It’s a bit hard to see the exact number on my mechanical caliper. Thank you!

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December 23rd, 2023, 05:55 AM	#2
Mohawk ninjette.org guru Name: Chris Location: Bristol, UK Join Date: Feb 2016 Motorcycle(s): ZZR250, VFR800 Posts: 478	You need to use a micrometer to measure the shim thickness. They are all different at the factory just like you they measure the clearance & adjust to the correct gap when new. As it wears in then the gap increases or decreases, hence the need to adjust it over time. The process to find required replacement shim is to measure the gap first for all valves & make a table of each valve gap. Remove cams & read or measure each shim size. Add shim size + gap per valve & then remove the required valve gap to find the new shim size required. You may be lucky & be able to move shims around & thus not need to buy many. Have fun.

December 24th, 2023, 10:30 PM	#3
Hogges ninjette.org member Name: Wolfgang Location: Vermont Join Date: Nov 2023 Motorcycle(s): R1200GS, DR200SE, Ninja EX300 Posts: 17	Wouldn’t the advantage of shimmed valve spacing be that the manufacturer can omit the individual adjustment? How would this even work? They would need to run the engine for a bit to give the valves a chance to settle in, then take everything apart again to measure and install the proper shims? This would be very expensive. Aren’t modern manufacturing tolerances able to omit this and use the same size for all bikes coming off the line, at least for a while?

December 27th, 2023, 05:49 AM	#4
Mohawk ninjette.org guru Name: Chris Location: Bristol, UK Join Date: Feb 2016 Motorcycle(s): ZZR250, VFR800 Posts: 478	I think you have a poor understanding of engine manufacturing. It is NOT 100% accurate, hence things like valve clearances have to be set for every valve. The engine does not need to run. They are set on a build bench when the head is built up as a sub assembly. Which then goes to the engine assembly line. The engine is only run once the bike is complete & gets its post assembly systems check. Engines are run by the manufacturer on a dyno & given real world duty cycles. They're stopped & inspected after various mileages to determine the maintenance schedules for various components, like valve clearances etc. So as previously stated every valve has an individual shim size that was correct when the head was assembled. Follow the recommended process to set your clearances correctly. Have fun.

December 27th, 2023, 08:09 AM	#5
Hogges ninjette.org member Name: Wolfgang Location: Vermont Join Date: Nov 2023 Motorcycle(s): R1200GS, DR200SE, Ninja EX300 Posts: 17	I don't know how the manufacturers go about this exactly. But my bike has all the same shims for all four valves and they only come in increments of 0.05mm anyway as per Kawasaki's service manual. Still seems reasonable to me that there is such a thing as a stock shim size in high volume engine manufacturing, eliminating the labor cost of individual screw and locknut adjustment of rocker arm designs. I'd be happy to find a video showing the assembly steps at the factory. Anyway, shims finally shipped and I look forward to putting this mess back together soon, and hopefully without messing up the timing, kinking the timing chain or dropping any parts into the lower engine.