2006 Honda CRF150F Transmission?

I recently bought a 2006 Honda CRF150F. I'm new to dirtbikes and this is my first bike. It is a blast and I almost want a 250 already. My problem is that switching gears doesn't seem very smooth. At a standstill holding in the clutch trying to get neutral sometimes it doesn't want to switch at all and I have to rock the bike to get it to switch. Also sometimes when in 2nd gear it slips into neutral. I change the oil regularly and put about a quart of Honda oil in. Any suggestions as what to do? Also is testing the engine compression the same as a two stroke? I'm used to 2 stroke snowmobiles.

2nd gear slipping into neutral is a common problem when bikes have been abused.
The shift forks ware and don't move the gears enough to fully lock into the adjacent gear.
Without a positive lock, the trani slips back to neutral.
Transmission repair is necessary.

Compression test is the same with 2 & 4 stroke engines.
Compression gauge in.
Throttle wide open.
Crank the engine.

Testing the compression is the same, as for the tranny you could try adjusting the clutch to get a better feel