Practiced bore-up at the same time as overhauling the upper part of the engine. However, the lower part of the engine is almost untouched by Kawasaki KZ550GP. During the test ride after the bore up, the clutch began to show some slippage condition, so I immediately incorporated the Advantage FCC clutch kit, also known as a reinforced clutch kit.
Clutch slippage can definitely be felt.
In hibernation motorcycles that have returned to public roads after a long absence, for example, engine rpm increases strangely while accelerating with the throttle open, or the engine rpm increases at the moment the throttle is opened for overtaking acceleration and the body of the motorcycle does not move powerfully forward and other condition often occur. Repeated clutch slippage causes the clutch plate to burn and deform, resulting in pronounced intermittent failure.
State-of-the-art clutch kit
Even though it may not look the same, Advantage FCC's clutch kit has evolved and improved with a different friction disc material and non-slip surface treatment on the clutch plate surface. The lineup ranges from the latest super sports models to old motorcycles, so check to see if there is a clutch kit that fits your motorcycle.
Open the cover without draining the engine oil
It is best to replace the clutch disc & plate at the same time as the oil change, but in some cases, due to the timing of the work, you may not want to drain the engine oil. Depending on the engine type and design, the engine oil may not flow out when the clutch cover is removed by securing the front brake lever with a side stand and lifting the rear area with a piece of wood under the rear tire. In the case of the Kawasaki Middle, there is an oil passage under the clutch unit from which oil flows out, so a rubber plug was inserted to stop it. In this condition, stable operation is possible.
Surprisingly easy clutch parts replacement work
The clutch structure, which is easy to maintain, was inherited from Kawasaki's first 4-cylinder model, the Z1, and many motorcycle manufacturers have since adopted the same type of layout. The five-bolt tightening specification is another Kawasaki feature. New clutch discs and plates should be "soaked in engine oil before installation" to soak the oil into the sliding material while washing out fine sliding material powder. The effect of this work is actually significant. On the left is Advantage FCC's reinforced spring and on the right is Kawasaki's OEM spring for KZ550GP. The specifications are almost identical to those of the 550GP, although they seem to be strengthened compared to those for the 400. The top and bottom polished finish with no spring collapse is an important factor for the clutch spring.
Correct assembly sequence
Clutch discs & plates soaked in engine oil are assembled in order. The chamfered side of the steel plate clutch plate convex and concave should face the engine side (back side) to obtain smoothness when the clutch meets. Apply a very small amount of molybdenum disulfide grease to the tip of the stick side of the so-called "mushroom air filter" that is inserted into the shaft center and to the top surface of the mushroom. It is to prevent galling in the early stages of assembly. In many later models, a needle bearing is inserted in this plate part. After the control plate is installed and the clutch spring is tightened, the clutch release must be adjusted. If there is not enough free play in this area, clutch slippage will occur.
What does it mean to "visually check" the clutch lift?
Before closing the clutch cover, repeatedly squeeze and release the clutch lever while peering over the seat directly above the clutch unit to see the intermittent operation of the clutch unit. When the control plate lifts to tilt, the springs should be rotated and adjusted so that the entire control plate lifts simultaneously and on average. Adjusting for the average lift will improve clutch disengagement. Unfortunately, the type with the release on the clutch cover side cannot be visually checked.
POINT
Point 1. If clutch slippage was felt, replace discs as soon as possible to minimize damage.
Point 2. New friction discs and clutch plates should be fully soaked in engine oil before assembly.
Point 3. Apply grease or other anti-gouging chemicals to each sliding part as needed.
Point 4. Adjust to the average lift up when the unit can be visually adjusted to the clutch lever operating conditions.
You may feel the same thing when you ride at full throttle with an engine that has just been overhauled or bored up. The same impression is often felt when a motorcycle is restored after being immobilized. Even if you open the throttle, the engine rpm only increases and it does not accelerate strongly. Yes, that is the symptom of clutch slippage. Especially, when you twist the throttle to accelerate for overtaking, the engine rpm only increases and the motorcycle does not move forward.
If the engine oil and gear oil (gear oil for 2-stroke engines) are not warm, clutch slippage conditions are likely to occur. However, if the engine is warmed up sufficiently, twisting the throttle will only increase the engine rpm.
While you may feel a little disappointed, you may actually be smiling at the increased power of the engine. However, be careful not to damage other parts of the engine if you don't fix these conditions as soon as possible.
This maintenance motorcycle, a KZ550GP, had never had its clutch touched since the motorcycle was purchased, so I did not hesitate to replace it with an FCC clutch kit produced by Advantage, which is also known for its reinforced clutch. FCC is the world's number one manufacturer of multi-plate clutch technology. The manufacturer is also known as a supplier of clutch parts to motorcycle manufacturers around the world. Advantage offers a lineup of such parts as replacement kit parts. The lineup of kit parts for various models ranges from basic kits of disc & plate + reinforced spring to complete kits including clutch basket (outer).
Several types of kit parts are lined up for the Kawasaki Middle Series alone, and details such as compatibility can be found on the Advantage Web. Since the Z500 was introduced in 1979, the Kawasaki air-cooled middle 4-cylinder series continued to be manufactured for nearly 30 years until the Zephyr-X was discontinued. Even though the basic design is the same, there are differences in the details, which is probably why multiple kit parts exist. After converting to the Advantage FCC clutch kit, the driver can now enjoy full throttle with no stress and with a good feeling.
