There are 3 hoses that run up to the idle sensor on the top of the motor. One of mine cracked and this aloud dirt to enter the motor after the air filter.
At present my machine may need an engine over haul. It has just over 3K miles on it. It seems these hoses have very thin side walls and flex while the motor is running and they fail. It is an easy fix to put automotive type hose in there place. Keep an eye on them or just replace them and be safe. Hope this was helpful. On another note, I have 1600 miles on my front drive shaft carriage bearing and it is still working fine. I replaced it with an SKF bearing and grease it each oil change. The factory bearing have been know to fail in less than 300 miles. If you need the part number let me know.