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What is the proper spark plug gap for a 1981 Yamaha XS400?
Asked in Yamaha Motorcycles
What is the proper oil filter for a 1981 Yamaha xs400?
Asked in Spark Plugs and Wires, Yamaha Motorcycles
What is the proper spark plug for a yamaha dt 175?
Asked in Motorcycle Law
What are the specifications for a 1981 Yamaha xs400?
Asked in Cars & Vehicles, Yamaha Motorcycles
What is the correct spark plug gap for a 1981 Yamaha xs650?
Asked in Yamaha Motorcycles, DIY Projects
How do you adjust the timing for a 1981 Yamaha maxim xj 650?
Asked in Oil and Oil Filters, Yamaha Motorcycles
What weight of oil is recommended for a 1981 Yamaha XS400 Special?
Answer: Given the make and year, I would go with a 10W40 viscosity. I own a Chilton's Motorcycle Repair Manual (1959-1981) and in the Yamaha XS360-400 section is states "When the average air temperature is above 5 degrees Celsius (41 degrees Fahrenheit), use Yamalube 4-stroke oil, or SAE 20W-40, service rating SE or SF. When air temperature is consistently below 15 degrees Celsius (59 degrees Fahrenheit), use SAE 10W-30, service rating SE or SF."