The provided documentation discusses Lockhart oil coolers, primarily in the context of Kawasaki KZ series motorcycles, specifically the ZN1100 and KZ650 models. The discussion centers on installation practices, the presence or absence of thermostats, oil drainage during maintenance, and the overall function of these coolers in relation to engine and clutch cooling. Users share experiences and insights regarding performance and maintenance, with varying opinions on the necessity of thermostats and the primary cooling function of the oil cooler itself.
Oil Cooler Functionality and Thermostat Considerations
The primary function of an oil cooler is to maintain optimal oil temperature, preventing overheating and ensuring consistent lubrication. Several users discuss the role of a thermostat within the oil cooler system. According to one user, Derale manufactured oil coolers with integrated thermostats. These thermostats utilize a bimetallic strip to regulate oil flow through the cooler based on temperature. When the oil is cold, the strip blocks flow to the main cooler passages, diverting it through a smaller passage. As the oil warms, the strip bends, allowing full flow through the cooler.
However, the documentation indicates that not all Lockhart oil coolers include a thermostat as standard equipment. One user states that unless specifically installed as an option, Lockhart coolers do not typically include a thermostat. Another user suggests that the absence of a thermostat is not a significant concern.
Conflicting opinions exist regarding the necessity of a thermostat. One user recommends a thermostat, particularly in colder climates, to facilitate faster engine warm-up. Conversely, another user asserts that the oil cooler’s effect is negligible when the motorcycle is stationary, and a thermostat is therefore unnecessary.
Installation Practices
The documentation details aspects of installing a Lockhart model 420 oil cooler on a motorcycle originally equipped for a 1980-1990s Sportster. The installation involved acquiring the cooler itself, hoses, hose clamps, mounting clamps, a thermostat oil adapter, and specialized hose ends. The user encountered a fitting issue with 90-degree hose bends, requiring a visit to a hardware store to obtain a suitable alternative. The use of 1-inch heater hose as a buffer between the cooler and painted surfaces was also noted to prevent damage.
Oil Drainage During Maintenance
A common question raised by users concerns ensuring complete oil drainage from the cooler during oil changes. The documentation indicates that complete drainage is difficult without disconnecting the hoses attached to the oil cooler. Gravity alone is generally sufficient to drain the oil from the cooler once the hoses are removed.
Cooling System Role: Engine vs. Clutch
A significant point of discussion revolves around whether the oil cooler primarily cools the engine or the clutch. One user emphasizes that the oil cooler’s main function is to cool the wet clutch, as the clutch is the primary component utilizing oil for cooling. This user draws a parallel to automatic transmission fluid coolers in automobiles. They argue that the oil cooler contributes to the longevity of the machine, even if its impact on overall engine temperature is less pronounced.
However, another user disagrees, asserting that the oil cooler does help cool the engine, not just the clutch. They point to motorcycles with dry clutches that still utilize oil coolers as evidence, arguing that the oil extracts heat from all internal engine components. They also note that maintaining optimal oil temperature is crucial for consistent lubrication.
Oil Temperature and Performance
One user with extensive experience running oil temperature gauges and coolers on Kawasaki Z series motorcycles reports observing oil temperatures exceeding 240 degrees Fahrenheit in stop-and-go traffic during hot weather. They advocate for maintaining an oil temperature of 180 degrees Fahrenheit to remove moisture from the engine. They also plan to install fans behind the oil cooler to further reduce oil temperatures in heavy traffic. The use of AMSOIL 10W-40 motorcycle oil is also mentioned as a preventative measure against internal engine rust.
Additional Considerations
The documentation references several forum posts and project logs related to KZ series motorcycle modifications. These references suggest a broader community interest in performance enhancements and maintenance procedures. The discussion also touches upon the use of specific oil types and their potential benefits.
Conclusion
Lockhart oil coolers are a common aftermarket addition to Kawasaki KZ series motorcycles, intended to manage oil temperature and enhance engine longevity. Installation can vary depending on the specific model and existing configuration, and the presence of a thermostat is not guaranteed. While opinions differ on the primary cooling function – engine versus clutch – the consensus is that maintaining optimal oil temperature is crucial for performance and reliability. Proper oil drainage during maintenance requires disconnecting the cooler hoses. The provided documentation represents a collection of user experiences and insights, offering practical guidance for owners considering or maintaining these oil cooling systems.