I changed the engine oil, warmed up the motorcycle, and started. As I was driving along the motorway, I spotted a slow-moving truck in front of me. I downshifted and opened the throttle in the overtaking lane, but what? The engine revs up and the motorcycle doesn't push forward. Wherever the situation may be, slipping clutch discs are often noticed when accelerating to overtake.
The clutch unit is located inside the engine on the transmission side, so the engine oil generally needs to be drained. However, in this case, as it was just after the oil change, we wondered if it was possible to work without draining the engine oil. In such a case, I recommend you to lean the motorcycle over for maintenance.
Lift the rear tire and start working.
The motorcycle being worked on here is a Suzuki GS1000, but the engine layout is similar for all Japanese parallel 4-cylinder models (even parallel 2-cylinder models), so there should be many models that can be worked on in the same way. It is possible to keep the body at an angle by turning the steering wheel to the right side and holding the left grip against a desk or table surface, but this time I put a piece of wood under the rear tire to make the body lean more.
Not only for this kind of work, but also during maintenance, it is always a good idea to keep the front brake lever locked in a "holding position". Locking the brake lever in this way, except when performing maintenance on the front end, will prevent the tires from spinning and the motorcycle from moving even if an earthquake occurs during work. When loading the motorcycle on the trampo, locking the front wheel will definitely stabilize the motorcycle. Here, I use a tire tube that I cut into a circle, but you can also keep a tire lock for trampo in your tool box.
Rear right side is clutch cover
Since the introduction of the Kawasaki Z1, the clutch unit layout for large motorcycles has been largely established. Today's latest liquid-cooled multi-engines are commonly referred to as "three-story engines" due to changes in the transmission shaft layout, but the wet-type multi-plate clutch unit layout is much the same. When the clutch cover is removed, the clutch unit can be seen inside like this.
Since this is a maintenance of a specific model (Suzuki GS1000 in this case), I think there are few cases like this in other models, but the gasket as it was when it was shipped new probably remained tight to the engine side. This time I had bought a new gasket beforehand, but decided to reuse it. I had already bought a new gasket to replace it when it was partially missing or broken, but I think I can reuse this one. However, there was a part of the gasket that covered the clutch unit, so I tore off the unnecessary part of the gasket with my fingertips so that I could pull out the clutch disc.
New discs go into a plastic bag.
Wet clutch disc, or to be more precise, "friction disc of wet type multi-disc clutch" is a part that functions in engine oil. Therefore, when installing a new wet friction disc, the correct answer is to soak it in engine oil before installing it. If the disc is not soaked in engine oil, the clutch may slip after the engine is started, or the disc may burn due to excessive friction, causing unnecessary contamination of the engine oil or warping of the disc. When installing a new friction disc, engine oil should be applied beforehand. In such a case, it is recommended to put a small amount of engine oil in a plastic bag and soak the friction disc in the oil. It is recommended to put a small amount of engine oil in a plastic bag and soak the friction disc in the oil.
The clutch springs were included in the Advantage FCC clutch kit that we installed. The feature of this product is that the friction disc for old motorcycles is developed with the compound for the modern high performance friction disc. Therefore, the spring rate of the clutch spring is lower than the genuine parts at that time because of the friction disc which has larger friction coefficient and less slippage. This is the recommended clutch disc kit that can be purchased as one set.
Magnetic bar convenient for pulling out plates
When removing the old friction disc or iron plate clutch plate, it is often difficult to remove the disc due to sticking by engine oil. In such a case, it is better to use a magnet bar for the iron plate clutch plate and a pick-up tool with tapered and bent end for the friction disc removal. If you have two of either tool, you will be able to work even better. If you have two spokes that you no longer need (bicycle spokes are thin and easy to use), you can easily make your own tool to remove the friction disk.
Install the new friction disc and clutch plate in good order after soaking in engine oil. There are bumps on the inside of the clutch plate, and it is combined with the clutch hub, and the clutch meet will be smoother by installing the chamfered and rounded bumps at the back. In some cases, the chamfered side is installed facing outward to improve clutch disengagement, but in general, it is installed facing inward (at the rear).
Since the old gasket came off cleanly without breaking during disassembly, I decided to save the new gasket. In such a case, we always want to use silicon-based liquid gasket. Silicone gaskets are the best and easiest to use when sealing the engine oil. Daytona's liquid gaskets are sold in small quantities and are really convenient.!!
I soaked a rag in parts cleaner, wiped the gasket surface to remove any oil, and then applied a thin layer of silicone-based liquid gasket. I applied it to both the gasket contact surface and the cover tightening seat before restoring it.
- Point 1: Keep in mind that tilting the motorcycle can improve maintenance, not just clutch disc replacement.
- Point 2: When installing a new clutch friction disc, soak it thoroughly in engine oil before starting work.
- Point 3: When it is difficult to remove the old clutch disc, you can use a pick-up tool or a magnet bar.
- Point 3: The gasket which peeled off cleanly without cutting can be reused by using liquid gasket together. It is better to think of it as a first aid, but when oil leakage or seepage occurs, replace it with a new gasket!
I often notice some changes or troubles at the timing like "I just changed the engine oil". There are many cases where the engine oil has to be drained out when inspecting the internal engine parts or replacing parts, so working at such timing is daunting.
Here is a suggestion. When you want to proceed with engine maintenance by removing engine oil that has just been replaced, you can easily reuse the removed engine oil by placing a 2-liter PET bottle horizontally and inserting a cutter blade into the top surface of the bottle to use it like a "waste oil pan". When refilling the oil jug, it is easy to check for foreign matter, and the spout makes it very easy to work with. For the moped class, a 2-liter capacity is sufficient, but for larger models, prepare two or three 2-liter PET bottles. For larger models, two or three 2-liter PET bottles can be used, not for drinking water, but for windshield washers. We are now in the age of eco-friendliness, so we want to reuse usable parts.
Since the clutch unit of the large engine is designed with an almost similar layout, the reassembly work and inspection like this should be easy to do by tilting the body. I have practiced similar maintenance before with Super Kap's "centrifugal clutch model". This is a Super Cub where the primary clutch is laid out on the crankshaft side. In the case of such an engine, I would like to recommend working with the vehicle body tilted greatly. Because the clutch lifter releases the primary clutch at the time of the gear change, and the structure is designed to mitigate the shock and vibration at the time of the gear change, but the clutch lifter (around the steel ball) is stuck at the time of restoration, and it is difficult to restore the assembly. When the clutch cover is removed from the Super Cub, the assembly around the clutch lifter often does not go well during restoration. That's why I would like to recommend doing maintenance with the motorcycle leaned over.
Not only clutch covers, but also gaskets sometimes come off cleanly when engine parts covers are removed, luckily (same with cylinder base gaskets). In such a case, proceed carefully so as not to damage the gasket while working, and when restoring the cover, degrease not only the seating surface on the cover side, but also the tightening surface on the gasket side. It is a good idea to soak a clean rag with parts cleaner and degrease the gasket by pressing the rag against it. In addition, if you use a silicon liquid gasket and apply a thin layer of the liquid gasket and restore it, there is little chance of oil seepage or oil leaks occurring. If oil seepage occurs, you can replace it with a new gasket. This kind of procedure is not allowed in the shop, but in the DIY maintenance of us Sunday mechanics, the high performance liquid gasket is often a real blessing. If you want to reuse the cylinder base gasket of 2-stroke engine, you should use gasoline resistant solvent type liquid gasket instead of silicone type, because the other party is not engine oil but gasoline mixture.
See KAWASAKI Moto Index Page
See SUZUKI Moto Index Page
See Accessories for KAWASAKI Z1
See Accessories for SUZUKI GS1000E/S
