Just acquired a 2004 Polaris Predator 500. Unit ran great and popped off everytime, however it leaked oil between the crankcase halves.
Tore the machine apart and resealed the case halves. Repalced all gaskets and seals. I followed the service manual to a "T" with regards to torque, timing, valve lash, carb cleaning, etc. I replaced the spark plug, checked compression (120 lbs.), I am getting fuel to the carb and all the lines are free of obstruction. The fuel filters on the petcock are both clean. I tried fresh gas. The choke cable is operational as well as the throttle mechanism. I even did a load test on the battery figuring maybe the plug would spark when there was no load on the battery but not when the engine was building compression. It tested fine. It sits at 12.6 V to start and only drops to 11.7 while cranking. I checked all the wiring and the pulse coil along with the stator and reverse coil. The only thing I have not tried yet is a leak down test.

The thing just will not start anymore. It cranks and cranks and cranks with an ocassional teaser of a pop through the exhaust (gets the hopes up). I don't get it. Very confused. What am I missing?????

I have worked on stuff like this for several years now and have never experienced this yet.

Rule of thumb: Fuel,Spark,and Compression = Running Engine.