1. Check for significant blue discolouration of the drive chain plates indicating excessive heat build-up.
2. Examine all pins for signs of rotation.
3. Check for cracking or deep scratching of the drive chain plates.
4. Check for severe wear of the inner plates as indicated in the diagram below.
For a more thorough check, proceed as follows:
1. Remove the drive chain from the engine.
2. Suspend the drive chain from a pin or hook with a 13 kg weight attached at the lower end.
3. Measure across 23 links as shown in the diagram below. If the drive chain is within limits, the measurement should be no longer than 149.48 mm. Measurements beyond 149.48 mm indicate that the drive chain must be replaced.
4. Check for severe wear of the inner surface of the outer plates at the side-contact points with the sprocket teeth.
5. Check for signs of stiffness or kinking.
6. Check for severe wear of the plates in the area shown below.
7. If any of these symptoms are evident, the camshaft drive chain must be replaced.