
Bikes been SORN off the road and sitting about 2 years

Battery is fine (I did charge it every now and again to keep it good)
I drained out the fuel, and put in 1 gallon of fresh.
Turn ignition on, choke out with no throttle (as I've read and found out this is the best way to start it)
Engine spins and spins and spins, and won't fire.
If I get lucky, I hear a few fires, but not enough to keep going.
If I get really lucky (as I have done 2 nights this past week) it does actually fire up enough to take some throttle (just) but it's a balancing act between choke and throttle, and if I don't nurse it gently it dies.
Once it dies, it won't re-fire and the engine will just spin and spin on the starter, and I think (perhaps) it's then too wet? inside and no point in trying again till the following day.
Any thoughts?
Thanks.
Oh yes, and just to make you aware of one thing.... I know the rectifiers are known for being a bit pants on VTR's, so in the past I took forum advice and fitted a Yamaha R1 much larger finned Regulator/Rectifier.