The engine oil is the chief factor affecting the performance and service life of your engine. Use only the recommended oil, and ensure oil is maintained at the proper level. Plan on changing the engine oil every 1,500-2,000 miles, or every 30-60 days. Once a month sounds like a waste of time and oil, but the time interval is as important as elapsed mileage. Acids formed by gasoline vapor will contaminate the oil, even if the bike has not run for several weeks.
How much engine oil do I need for my CB350 / CL350 / SL350?
CB350 / CL350: 2.1 U.S. Quart / 2 Lit.
SL350: 2.3 U.S. Quart / 2.2
What engine oil should I use for my CB350 / CL350 / SL350?
Use only a detergent oil with an API rating of SD or better.
Recommended oil viscosity for general riding and all temperatures is: SAE 10W-40. We recommend adding 2oz. of Zinc ZDDP additive per quart of oil with every oil change.
We've also had success running diesel truck oil at 15W-40 viscosity. Diesel oil has the bonus of extra detergent additives. Synthetic oils are not recommended as they will cause your clutch to slip. As of late 2023, Shell Rotella T4, Chevron Delo 400 and Mobil Delvac 1300 are now a semi-synthetic oil and cause clutch slippage in these engines. Be sure that any oil you are using is still 100% mineral oil.
Engine Oil Change Instructions
Note: Be sure to drain the oil while the engine is still warm. This will help assure complete and rapid draining. Make sure the motorcycle is in an upright, and level position during the oil change.
1 ) Remove oil filter cap from right crankcase cover.
2 ) Place empty vessel under crankcase to catch the oil. Once that's in place, remove the oil drain plug located on the bottom of the engine. (Wear gloves! This step can get messy.)
3 ) After the oil has stopped draining from the crankcase, crank the engine using the kick-starter several times to drain any oil that may be left in the recesses of the engine.
4 ) When the oil has been completely drained, reinstall the drain plug.
5 ) Fill the crankcase through the oil filter opening with the recommended grade oil. Check the oil level with the filler cap dipstick (do not screw in the cap.) The oil level should be between the upper and lower level marks on the dipstick.
Your oil rotor and filter needs to be cleaned and change every other oil change.
(instructions, parts, and video)
Recommended Drain Plugs:
Be sure to also complete your cam chain adjustment, valve adjustment, and ignition timing during each oil change or every 1,500 m / 2,400 km:
Honda CB350 Engine Valve (Rocker Arm) & Cam Chain Adjustment
How to set the ignition timing on the Honda CB350 / CL350 / SL350