Lucas Primary Chaincase Oil Review [and How

During the latest oil change for my 1999 Harley-Davidson Sportster XLH883, which has 43,349 miles on the odometer, I also changed the primary chaincase oil using Lucas Primary Chaincase Oil—it’s all part of the power transmission system.

Even though there is no filtration of the chaincase oil in the air-cooled Harley-Davidson Evolution motor, I tend to not change it at every engine oil change because the chaincase’s operating temperature is lower than for the engine oil. Also, contamination by combustion by-products is not a factor. When I had changed the chaincase oil at every engine oil change, I noted the outgoing oil was virtually as clean as the new oil I was pouring in; that led me to consider doing it on every other change.

My Harley-Davidson Sportster owner’s manual calls for the chaincase oil change at about 5000 miles under normal operating conditions—about when the engine oil change would be due. Also, the primary drive chain was scheduled for a check-up, adjustment if indicated, and an oil change, so I did all that during this maintenance chore. Always follow the manufacturer’s recommendations for the frequency of fluid changes, along with the lubricant specifications.

The chaincase hex-head drain plug is located directly under the clutch cover. The drain plug includes a magnetic end to trap ferrous metal particles and collect a little sludge from inside the case.

Once that is cleaned and the chaincase draining is done, and the inspection port near the top edge of the case is removed, the chain condition and tension can be inspected, and any adjustments made. I give the screws that hold the inspection cover and clutch cover on a shot of Liquid Wrench to make them easier to remove and reduce the chances of stripping the heads. If they still don’t want to come loose, I use a tap or two with an impact driver.

The 1999 Harley-Davidson Sportster XLH883 primary chaincase holds a quart of lubricant that has to go in with the clutch cover removed. It’s a little awkward to get at, as most conventional funnels tend not to be quite right for the job. I’ve found that a fuel system anti-freeze bottle with one side cut off and the interior cleaned and dried makes a handy funnel to do the job. Sometimes, you have to improvise.

The technical data Lucas provides for the Primary Chaincase oil points out that the oil is formulated to carry away more heat from the clutch and friction plates, which can contribute to a longer life for those components. The viscosity index for the product is 150, indicating the viscosity is stable over a wide range of temperature conditions. That is good news for those of us who will ride in temperatures ranging from a little above freezing to triple digits.

With the chaincase oil refreshed, any primary drive chain adjustment that may be necessary completed, and a dab of thread locker on each of the small screws fastening the inspection and clutch covers, things can be reassembled, and the old Sporty is ready for the road with a fresh supply of Lucas Primary Chaincase oil.