What oil type to use when changing engine oil in a c50 boulevard?

Question edited for a lot more clarity. 'see 50' to 'C50', add Maker.
Question moved to model category.

https://www.google.com/search?q=boulevard+c50+replace+ignition+switch

Should be bottom center of the engine.

First drain the oil from the engine by un-doing the oil drain plug at the bottom of the engines oil pan. Once most of the oil drains replace the oil filter. The oil filter on a Suzuki Boulevard c50 is located just below the gas tank on the right side of the motorcycle. The oil filter is a round assembly that is typically black or chrome and can be removed using an oil filter wrench. Put a bit of oil around the gasket on the new filter and screw it on tightly by hand. Put in the drain plug and fill the engine up with oil (check the oil level glass window with the bike in an upright position to make sure you have enough oil in the engine block)

Sorry, no dipstick; the oil level is checked at a sight window low on the right side of the engine. This is best done with an inspection mirror, as the bike must be held level to read accurately. Side note: when changing the oil filter, make sure that the rubber gasket of the old filter does not stick to the bike- some have failed to notice this, causing a total loss of engine oil while the bike is running!

One and the same- that is why, if you use an oil that is not motorcycle-specific, make sure that it does not have the "energy saving" label in the grade rating emblem. I have run Shell Rotella, both dino and synthetic, for most of the 32K of my Boulevard.

As long as the oil does not have the "energy saving" designation in the rating emblem, synthetic work just fine in the Boulevard.

engine case vent bad . does engine heat up and then shut down?

well some manufactures do recommend this ,they feel there engines operate better and not cause any problems...but personaly i would change the filter at that time..for peace of mind!!

It takes 10w40 oil and 3.2 qts for oil change only and 3.6 qts for oil and filter change.