Issues starting bike after it has been ridden for a while...

[daymay801]

So I just finished my bike and have had a couple issues with it, it starts and runs great, but after I ride id for about 30-40 minutes and turn it off it doesn't want to start back up.
It doesn't seem like a fuel issue, and at first I thought maybe it wasn't charging but I checked the leads coming off the stator and they are pushing out plenty of voltage.
Any ides on what this could be?
I was thinking maybe the coils are overheating so they aren't sending spark? Or maybe I have a bad ground somewhere?
Any help would be great! Thanks!

 

[gggGary]

Crank it (kick it) for a while and pull the plugs, wet = ignition problem, dry = fuel if they they are dry try a little ether if it fires, float level? tank vent? TCI, points, or pamco? How does the spark look when you kick it hot? Check valve clearance recently? Does compression feel strong? Check timing with a timing light if points or Pamco advance correct and progressive?

 

[daymay801]

I adjusted the floats and it seems to have fixed a lot of problems, but now it is backfiring from a lot from the left cylinder when I let off the throttle? And I can hear a light rhythmic knocking sound on the same cylinder, how do you check valve clearance?

 

[gggGary]

synch the carbs.
Any XS manual shows the technique, it's about as easy as any engine gets for setting valves.
http://www.biker.net/650parts_index.html

Check your cam chain too. Do not delay on checking timing with a timing light. Out of range timing can be cured. Advanced or sticky timing will hole a piston in short order. A knock is a very bad thing on these engines.