Among the many out-of-print motorcycles, the Kawasaki Z1/Z2 series has been favored by many fans of all generations. As the older motorcycles are more than 40 years old, they share a variety of problems and weaknesses, but oil oozing or leaking from the alternator stator harness grommet is one of the most common problems with Z-series motorcycles. Here are some tips to improve the effectiveness of maintenance among the countermeasure methods using external parts.
The cause of the oil leak is heat, age, and installation location issues.
The alternator of the Z1/Z2 series is soaked in engine oil, and the stator coil fixed to the alternator cover side is also spinning with oil. Because of this condition, it is inevitable that oil will leak if the adhesive on the grommet seen in the lower left corner deteriorates. The stator coil harness can also have oil penetrating quite far upstream due to capillary action.
To say "everyone's favorite" is an exaggeration, but the Kawasaki Z1/Z2 series has been shining at the center of out-of-print motorcycles for the past 20 years. Although it is the fate of out-of-print motorcycles that the number of motorcycles decreases as time goes by, the popularity of these old motorcycles, which have been out of print for almost half a century since their debut, continues to grow as parts manufacturers re-produce them and Kawasaki Heavy Industries re-produces cylinder heads.
What is it about Z that appeals to you? The reason for this is different for each person, but no matter how popular they are, they are still old motorcycles that have been manufactured for decades, so proper maintenance is essential if you want to keep them in good shape.
One of the most common problems you may notice around the engine is oil leaks and oozing. Some people use the excuse that oil leaks are evidence of oil in the system, but it's better not to leak, of course.
A typical oil leak point common to Z1 to Z1000Mk II and 750s of the same age is the grommet under the alternator cover on the left side of the engine. Inside the cover is the alternator stator coil, and the three cords of the coil, which is powered by three-phase alternating current, are led through the rubber grommet to the outside of the cover.
The engine oil is circulating inside this cover, so the oil is leaking through the gap between the cover and the grommet and the three holes where the cord goes.
Whether or not the alternator is soaked in engine oil depends on the model, but at least the Z1 series has oil going around here. However, the inside of the cover isn't all submerged, so if the part of the cover where the cord goes through was on the top side of the cover, the chance of an oil leak would have been reduced.
However, I can imagine that this would detract from the aesthetic appeal of the cover, so they decided to pull it out from underneath the cover, which is inconspicuous.
After 40+ years in an oil-soaked environment with the heat of the engine, it's inevitable that the grommets will deteriorate over time. It's not uncommon for the stator coil harness itself to be soaked in oil for a long time, allowing oil to penetrate between the outer skin and the core wire by capillary action.
In order to solve such problems, a replacement harness kit is now available from a company that actively develops and sells Z series repro parts. With these parts, you can replace the grommet that leaks oil and the stator coil harness that has hardened from oil leaks and heat from the engine.
- Point 1 - Oil leakage from the alternator cover is a classic symptom of the Z1/Z2 series
- Point 2 - Grommet hardening over time is inevitable.
Harness replacement is not difficult, but don't be impatient.
Replace the alternator cover grommet and stator coil harness with repro parts (in this case from Doremi Collection). Before replacing the harness, check the stator coils themselves for burned out or broken wires before replacing the harness. The wires can be connected by crimping the sleeve ring that comes with the harness kit, but I also used solder for a more secure connection.
When replacing the stator coil harness, you will need a cover gasket to remove the alternator cover. It's also a good idea to do this at the same time as the oil change to drain the engine oil.
What I am introducing here is an example of work on a 1976 KZ900LTD, but both Z1 and Z1000 are identical in content. This motorcycle is low mileage with less than 7,000km from new, but even so, oil had penetrated the wiring of the stator harness and lost flexibility, and engine oil was leaking out of the grommet part.
Replacing the harness requires soldering to remove the old harness and connect the new one. This can be done with the stator coil still attached to the alternator cover, but it's best to remove the coil and degrease it thoroughly to ensure that the stator coil leads are connected to the new harness, and to do this in an area where there is plenty of space.
Also, when connecting a new harness, run the three wires through the grommets before you solder the three wires and the heat shrink tubing that insulates the soldered area. Don't be too hasty, don't be distracted by the grommets after soldering, and be stunned.
After soldering the harness and covering the heat shrink tube, install the stator coil to the alternator cover and set the grommets in place. If there is any oil left on the cover side at this time, the adhesive applied to the grommet will not be as effective as it should be, so degrease the grommet carefully beforehand.
At this point, if the stator coil is connected to the stator coil harness with the stator coil still attached to the cover, engine oil can flow from unexpected places. If you remove the stator coils, the alternator cover can be removed and the alternator cover can be left alone.
- Point 1 - Replace the alternator cover grommets at the same time as the stator coil harness.
- Point 2 - Alternator cover degreasing is important to allow the glue to stick.
Once the grommets are glued on, they're locked in place and waiting.
Once the stator coils are installed on the degreased alternator cover, the grommets coated with Cemedine Super X are set in place. The Super X starts to cure initially in a short time, but you'll want to add a little extra work to push the grommets deep into the grooves to cure.
The grommets are crimped by clamping the aluminum angle material with a C-shaped clamp. By choosing the material that will be twisted with the surface to which the cover will be attached, it can be installed on the engine without any later modifications. The 3-wire sleeve cover of the stator harness is tucked up and temporarily secured with tape to prevent the glue from sticking to it.
The new grommets that separate the alternator cover inside and outside will be glued on, but the adhesive used is best if it is heat and oil resistant, seismic resistant, and has good fleshiness.
Many mechanics in out-of-print motorcycle shops love Cemedine's Super X series as an adhesive that satisfies such greedy requirements. As the catchphrase "Super X" implies, Super X is characterized by its ability to maintain moderate elasticity like rubber even after curing, and it has excellent heat and water resistance. It is also suitable for bonding metal and rubber, and it is an excellent material that was created for alternator cover grommets.
It is important that the glue is pressed down firmly until it cures, not just on the Super X. Even grommets that have been glued on should be allowed to cure with the alternator cover intact, rather than being assembled to the engine with it freshly applied.
You need to make sure that the cover and the grommet are tightly fitted. You just need to clamp the grommet with the C-shaped clamps. Apply a little bit of oil on the angle material instead of the mold release agent to prevent the glue from sticking to the grommet, and fix the grommet to the edge of the cover. It can be demonstrated.
If you seal it so carefully, it won't leak again in a short period of time. It is important to take the time and effort to do this simple work in order to maintain the beauty of your famous motorcycle.
If you remove the angle material after the adhesive has cured, you'll see that the end faces of the cover and grommets are perfectly aligned. Super X remains elastic even after it cures, so the area where the three yellow lines pass through will not crack and will maintain its seal.
Once the alternator cover is installed, the oil leak protection is completely invisible. Even owners who stick to the stock style may find it easier to accept the improved quality in the hidden areas.
- Point 1 - Elastic adhesives are the best way to bond grommets
- Point 2 - Allow the adhesive to cure by crimping before assembly to the engine.
See KAWASAKI Moto Index Page
See Accessories for KAWASAKI Z1 (900 Super Four)
See Accessories for KAWASAKI Z2 (750RS, Z750 Four)
See Accessories for KAWASAKI Z1000 MkII (KZ1000 MkII)
