So I'll try to keep it short but detailed. I have a 03 mountain cat 900 that I just rebuilt the top end. I took it out on the 1st ride and it ran awesome. Had no issues tell I shredded a belt. I didn't have a spare (LIKE A JACK) so I ended up getting pulled back. It took it for a 2nd ride last weekend and it ran like crap. It was boggy and could tell right away it wasn't running right. Also mid week I took my tank off to weld on my handle bars. For a extra safety precision I started my sled for a sec to run the gas out of my line and into my pluse pump and carbs seeing I was going to be welding right above my line.(problem could be from barley running out of gas) So after the ride I brought it back in the garage to see what the problem was. It has spark it's getting fuel and it blows my finger off the cylinder(don't have compression tester) so it has compression. So i started it up to see if it was what I initially thought running on one cylinder. I pulled the mag side plug wire and it dropped for a sec in rpm's then back to normal pulled the pto side and it died. Dead cylinder on mag side right? Well the weird thing about it is if I pull the wire on the pto side while giving it gas it will stay running but like crap. Please tell me it's not a crank bearing or something with the crank because of that pos belt. Also power valves are working good and look fine just put new reed in as well so they should be good.