I have a 2012 600 snyper. Bought it cheap because the engine was gone. Replaced the cylinder,piston,rings,timing chain,guides. Ran great but no real speed. I read on here to check the fuel pressure. C/o the fuel pump. Ran awesome for about 3 months then quit. No power to the fuel pump. Checked the wiring and now the pump works. But the engine won't run. It tries to start but backfires. Sounds like a timing problem. Any ideas? Totaly stumped on this one.

[2015 Z Force 800 53/Trail EPS]

Take the manual and check all the basics like valve timing, crank position sensor, fuel pump voltage,pressure and volume, tank vent check valve, spark, valve lash settings, compression...ect. If it has fuel and air in the right ratios along with proper compression and detonation at the right time, it will run. You just need to find out what's lacking.

I've checked the timing marks as per the manual. They are ok. Fuel pressure is where it should be. Changed out the spark plug. I have no idea why the timing would be off. If it was the crank sensor it wouldn't try to start would it? I

trying to start and backfiring tells me you are getting spark and fuel. Did you check compression? after the compression check then I would be looking at crank/cam sensors (if it has cam sensor kinda doubt it) fuel injectors for leaking or something. Or a restriction in the intake?