Never trust the manual...lol. I did and it filled my air box with oil. I put 3 liters in, go for a ride around town and then top it off when the engine is warm. The black plastic dipsticks make it a little hard to read the oil level so I drilled three very small holes in the fins of mine. One at the low level, one in the middle and one at the top mark. When you hold up the dipstick, light hits the hole with oil in it and it’s much easier to see check the level.