Red Line Synthetic Oil V-Twin Primary Case Oil is a friction-balanced synthetic lubricant formulated for 1984 and newer V-Twin American motorcycle engines. It is suitable for Harley-Davidson-style M8, Evolution, and Twin Cam engines, as well as compatible aftermarket engines with similar primary-drive designs. This 1-quart formulation is intended for primary chain cases equipped with wet clutches and is also suitable for the primary cases of older British motorcycles when the manufacturer specifies a comparable fluid.
Designed to support clutch performance, Red Line Synthetic Oil Part Number 42904 helps improve clutch operation while reducing wear and operating temperatures. Its friction balance provides the controlled slip characteristics needed for smooth engagement, unlike many automotive-style synthetic oils that may be too slippery for wet-clutch applications. The formulation can also help transmit power effectively in modified engines while maintaining consistent primary-drive performance.
Fitment: For 1984-to-present V-Twin American motorcycle engines, including M8, Evolution, Twin Cam, and similar aftermarket engine designs. Verify the motorcycle manufacturer’s primary-case fluid requirements before installation. Add the recommended amount for the specific motorcycle and service the primary case according to the vehicle manufacturer’s maintenance procedure.
Manufactured by Red Line Synthetic Oil, this V-Twin Primary Case Oil is supplied in a 1 US quart container and carries manufacturer part number 42904. Its specialized wet-clutch compatibility makes it a practical choice for riders and technicians seeking dependable primary-chain-case lubrication and smooth clutch response.
Features:
- Application: For 1984-to-present V-Twin American motorcycle engines and compatible aftermarket engine designs
- Engine Compatibility: Suitable for M8, Evolution, and Twin Cam engines
- Primary Case Use: Formulated for primary chain cases with wet clutches
- Clutch Performance: Helps improve clutch operation with smooth, controlled engagement
- Wear Protection: Helps reduce component wear and operating temperatures
- Friction Balance: Provides less slip than many overly slippery synthetic oils while supporting effective power transfer
- Alternate Fitment: Suitable for primary cases in older British motorcycles when a comparable lubricant is specified
- Brand: Red Line Synthetic Oil
- Manufacturer Part Number: 42904
- Package Size: 1 US quart