This is real simple and can be done in twenty minutes max. If you feel even slightly ambitious, you can easily do it yourself by checking the instructions and pictures in the 700/900 FAQ: Engine: Seals, Belts, Vent section.

The flame trap seldom needs to be replaced, merely cleaned. Use some solvent or carb cleaner and a pipe cleaner to dissolve gunk, and blow through the little hose to make sure that is clean as well. The only thing that can go wrong is (1) a split flame trap hose (get another from the dealer or www.ipdusa.com); (2) a crack in the flame trap body at the tee (just buy another). If you don't want to get too dirty or you are concerned about breaking something, then buy the flame trap kit from IPD for about $8 and replace everything.

You should clean the flame trap once per year, or use synthetic oil to minimize gunk buildup.