A few things that can lead to having trouble finding neutral are as follows.

1. Improper clutch adjustment or cable adjustment.

2. Primary fluid level too high.
It should be premeasured or just up to the bottom of the clutch basket with the bike upright and level.

3. Poor quality trans fluid.
You will see a marked improvement using a gear oil over the dealer installed syn 3 oil.
20/50 oil is motor oil and not the best choice for transmissions.

Some choices here in gear quality oil are...

Spectro platinum 6 Speed oil
Mobil 1 gear oil
Redline shockproof heavy gear oil
Bel ray gear oil
75/90 or 75/140 are both acceptable.