Hey everyone im new to the forum but hope someone can help! I have a2003 Polaris Predator 500 that was a cheap craigslist find, i know what more can i expect. Lol anyways it was cheap and i have had good luck with previous fixer uppers before, Well when i got it the seller was original owner and the motor i was promised is stock. It looks like its seen its fair share of rides but he told me it was just idling rough and a little backfiring when it last ran but it hasnt been rode in almost a year. Well when i got there the filter was kinda ghetto and filthy and i assumed prob filter and carb rebuild. Well got it to start in about 2 minutes after getting home and noticed it was a little rough and after a ride up the street a few times a few backfires. I also noticed a loud ticking from the top end of the motor. well i didnt wanna run it much so i parked it did a little online research and decided maybe timing chain or something so i opened up the top and seen it was a little off time so i set timing and but back together, well it idles great and not backfiring but still knocking. Chain seemed very tight so id assume not stretched so i drained the oil to find metal on the plug. not real fine but big enough to be worried. So today i pulled the whole top end off expecting to find a bent valve or some damage on the piston or something but valves look like they have a lot of carbon but no pitting to be found and luckily piston looks great! the only metal i found was under one of the buckets where the shim goes was sever shards, the other three where clean? well thats all i know and hope i can get further advice asap. Thanks for reading this long post just trying to be as descriptive as possible, im fixing to take our the oil filter and give it a look while im waiting on some expert advice lol Thanks guys!