Hi just thought id throw my 2 bob in the ring on this one
I have an 81 model XT500 and it took me a while to learn the starting tricks, but now it can sit there for months and still will start first go.
One thing i will stress is when i stop the engine i always give it a quick rev (about half throttle) then hit the kill switch as its winding down, NOW the trick i have found is vital in 2 points , when i go to restart hot or cold DONT TOUCH ANYTHING if cold put the choke on full if hot dont.
That rev you give it seems to leave just the right amount of fuel in the carb to restart. Now the most important point i can give is MAKE SURE YOUR ON A COMPRESSION STROKE dont worry about the TDC indicator with my old girl the kick starter engages a little further forward on the compression stroke than an exhaust.
OK now lay into the kick starter and dont be a pussy with it cause as many will know 500's can bite pretty hard.
Well thats the way i start a 500 hope it helps