Valve Shim Calculator Instructions (v1.3.5)

A simple web application to help you record and calculate the valve shims needed to get the correct valve clearences for bucket and shim type cylinder heads.
Works up to 4 cylinders and 16 valve engines. If you hase less cylinders or valves just enter 0 for those you dont need.
Allows you to load some test data, load your previous data or save your data to a file to reimport later.
The application also gives actual shim sizes but also sizes for shims in the 0.05mm selection range as this is what most shim kits contain.
There is some data validation on entry to help you identify any erors.

How to get Measurements?

1. Ensure the engine is cold
2. Remove tank, fairings, wiring, etc to access valve cover.
3. Remove the valve cover.
4. Follow instructions to measure valve clearances.
5. Insert the gap found in step 3 between the exhaust cam lobe and cam follower in the exhaust gap section and the gap between the inlet cam lobe and cam follower in the inlet gap section (Rectangle).
6. If needed remove the cam shafts and cam followers
7. Measure the shim thickness and enter in the exhaust and inlet shim sections (circles).
8. Look up your bike valve tolerances and enter relevant values.

Example: If the exhaust tolerance is 0.24mm to 0.30mm then enter the mean 0.27mm and precsion of 0.03mm and the inlet tolerance is 0.13mm to 0.19mm then enter the mean 0.16mm and precsion of 0.03mm`

Calculate shim adjustment

Press the Calculate Button

This provides 4 tables:

1. Exhaust valve readings and calculations
2. Inlet valve readings and calculations
3. Shim sizes (rounded size if you have a 0.05mm shim kit)
4. Shim sizes (actual size if you have all shim sizes)

The Calculate and save buttons will be enabled when you have entered all required data

If the colour is red the clerance is out of tollerance
If the colour is orange the clerance is in tollerance but not exact
If the colour is green the clerance is perfect

Save your measurements

Press the Open Calc Data Button

Example file

ValveShimCalculatorv1.3
0.3,0.15,0.13,0.25,0.25,0.2,0.28,0.25
1.5,1.65,1.65,1.5,1.5,1.53,1.5,1.55
1.55,1.45,1.68,1.65,1.60,1.70,1.67,1.65
0.25,0.25,0.15,0.13,0.18,0.13,0.15,0.15
0.27
0.16

Line definition

• ValveShimCalculatorv1.3 [file ID and Version]
• 0.3,0.15,0.13,0.25,0.25,0.2,0.28,0.25 [Exhaust Valve gap]
• 1.5,1.65,1.65,1.5,1.5,1.53,1.5,1.55 [Exhaust Shim thickness]
• 1.55,1.45,1.68,1.65,1.60,1.70,1.67,1.65 [Inlet Shim thickness]
• 0.25,0.25,0.15,0.13,0.18,0.13,0.15,0.15 [Inlet Valve gap]
• 0.27 [Exhaust tolerance mean]
• 0.16 [Inlet tolerance mean]

Load your measurements

Press the Download Calc Data Button and select the formatted file

Contact

ernie.sebright@gmail.com