How to adjust valves on a shim under bucket system
If you do not know how to get to the cams (under the valve cover) please pay someone to check your valves. This tutorial is generic (Kawasaki zx6 is used as a model) and you should consult your maintenance manual for specific instructions. You also will need some tools, like a digital/dial caliper or better yet a micrometer. Feeler gauges and general tools will also be needed.
Caution: If you perform this task incorrectly engine damage could/will occur. Proceed at your own risk
Tools required for checking valve clearence. Photo also shows valve train assembly but you will not remove valves for clearence adjustment. The bucket and shim are shown in the upper rt hand side of picture.
1 Gain access to cam/ cams and timing end of crankshaft (usually the end away from the alternator side)
2 Rotate crank shaft until the cyl.l # 1&4 align with the alignment mark or pointer. The Kawasaki pictured uses the case split line as a reference pointer. If you are not sure where the pointer is, remove #1 spark plug and place long screwdriver into plug hole. Rotate engine until the piston pushes the screwdriver to the highest level. Do not allow the screwdriver to get jammed in the plug hole. Look at the crankshaft end and the 1&4 marks should be aligned with some feature of the engine such as a pointer.
3 Pistons # 1&4 go travel in unison but 360 degrees out of cam timing phase. What this means is that when the timing marks are aligned only one cylinder is under compression and that is where we want to take the valve clearance measurements. Hint: The cylinder under compression will have the cam lobes pointing at a 45 degree angles.
So place a feeler gauge between the cam and the shim bucket. Use different sizes until a slight drag is felt between the bucket and the cam. Write down the feeler gauge size that was a good fit on all the valves for the cylinder that is being checked.
This is what the cam lobe position should look like before you use a feeler gauge
This picture shows the feeler gauge in use
4 Rotate crankshaft until the pistons # 2&3 mark is lined up. Follow the instructions in step 3.
5 Repeat until all the valve clearances are measured
6 By looking at your measurements and the specifications in the maintenance manual you will be either finished or looking on in this write up. Most bikes require a check and not a full adjustment.
7 In order to adjust the valve clearance the cams may have to be removed.
To remove cams read on
8 Remove the cam chain tensioner and cams. Do not drop timing chain into the engine. Use wire to secure chain. Do not rotate engine with a loose chain as engine damage could occur.
9 After cam removal remove the shim bucket by use of a magnet and remove shim.
10 Measure the shim thickness by use of a micrometer or calipers
11 When you have the shim dimension you can calculate the needed shim. Example: Your valve clearance should be .008”-.012”. Your valve clearance measurement came out to .006”. Your shim thickness dimension is .110” You will need a shim that is at least .002” thinner to meet the minimum valve clearance dimension of .008” So, your shim thickness should be between .104”and 108”. A shim thickness of
.106" would be ideal as it places you in the middle of the acceptable range.
12 Reinstall the cams. Take notice that there is an intake and an exhaust cam. Line up the cam timing marks and check to make sure the crank did not rotate by checking the crank shaft timing marks. The picture shows the cams without the camshaft caps. The intake cam shows chain slack that will be taken up by the CCT after instalation. There shoul be no slack between the exhaust cam sprocket and the crankshaft sprocket after CCT installation
13 Place cam cap cover over cams. Torque cam cap as per manufacturers instructions or you will damage the cam cap. This part is line bored at the factory and if you should damage it you will be buying a new head as the head and the cap cover are sold in pairs only.
14 Before installing the Cam chain tensioner you must first retract the CCT piston by rotating end of tensioner (through the end hole) until the piston is fully retracted. If you fail to do this step engine damage will occur.
This pix shows a fully retracted and fully extended CCT
15 Once the CCT is installed you must release the CCT by turning the CCT piston until it rotates foreward under its own spring tension. Do not force the piston forward after it contacts the chain or engine damage will occur.
Do not rotate crankshaft before releasing the CCT piston or engine damage could occur
16 Double check the timing marks
17 Rotate the engine at least 2 times to make sure the valves do not hit pistons
18 Put all of the removed parts together, leak check valve cover and go for a ride