Sounds like the timing is off. I helped my boyfriend go through the carbs on a friend's bike (streetbike) and it did about the same thing. He adjusted the timing and it fired right up. Now, how you adjust the timing is another question and I can't answer that!
As for starting the bike, I can only start my 94 if I follow the primer drill:
Gas on, full choke on.
Lean it over to the left until some gas comes out the vent tube.
Stand it up and let just the weight of my foot bring the kickstarter down 3 or 4 times.
Bring it back up and KICK it - no throttle.
If it doesn't start in 3 kicks, I start over but hold the kill button down while doing the slow kickstarter prime.
Usually fires right up by the second go around, even in cold weather.
BTW, it isn't necessarily leg strength, it's more technique. Heck a little ole girl like me can do it, once you get the technique down. (Of course I have never lacked in leg strength ;) )