I've had gas on my VX for 2 years now, no problems, running it with my YT rockers, exhaust etc. I did have problems in the 1st year, and that is only because i wasnt changing my plugs as regularly as i should have (10,000k;s).Electrics are the key to gas, poor leads, plugs etc = backfire. A Tune up only costs $15 and checks your mixtures etc. I'm planning on getting my heads ported now and hardened valve seats. Make your your cooling system is good as the coolant runs through the mixer to heat it up to stop it freezing over. Some people suggest 81^c thermostat to run it through quicker as gas it wamer and better to cool mixer as quick as possible. Run a Moreys Dripper lubrication system ($70) until you can get hardened seats.(If needed). The performance of you injectors will suffer after a while on gas as they dry out, build up etc. But who cares ! You got gas...it only needs to start up on petrol. Also your engine will stay cleaner.
Also, use a slightly thicker oil, so if you using 10W40 use a 15W 40-50 etc etc. This is cause the gas temperature plays with the oil visco, and change oil regularly(5,000-10,000) as acid build up due to gas.