I'll strongly encourage you to keep the automatic vacuum operated petcock. The 'Air Injection System', you can use your own judgement, as regards time required to servicing valve tappets.
Paul, why do you say that, recommending to keep the stock vacuum diaphragm petcock? I hate them, seriously, as they are known to fail, cause problems (erratic running, etc.), whereas the Yamaha Raptor petcock is ultra reliable. I've done the diaphragm removal/block off mod on a couple of stock petcocks, but use the Raptor petcocks instead.
I can appreciate the risk of having a float valve stick in the carb, and (with petcock left on) that fill the crankcase (with gas), spill gas all over the place, burn your house down etc. ...but, when parked indoors I think it's wise to shut petcocks off, diaphragm operated or not!
For those that think that's an unlikely scenario, bike catching on fire, one parts bike I bought had caught on fire... was all scorched/damaged right around the petcock area. (leaked).