I'll second the Murph's replacement petcock. Easy installation, no problems, works great. I was really worried about any hydrolock problems, since when I bought the bike, the original petcock had been left in the prime position. I've also had problems with the EX500, had to rebuild the petcock on that one after I noticed the oil level rising in the sight window. So, call me superstitious, but now I always turn the fuel off when I turn the bike off. Well worth the peace of mind.