Need help quad wont start

[TM426]

I helping a friend who has an 05 YFZ. It cranks real slow fully charged with a new battery. We checked all connections and all are tight. If the spark plug is removed it cranks normally. Everything is stock. My guess is the decompression plunger may be stuck. I just dont want to take the valve cover off for a simple fix. Any help is appreciated.

[Colby@C&DRacing]

I think you are looking in the right dirrection. Take the valve cover off and check the plunger.

[TM426]

Ill give it a look. Thanks for the help.