damn oil lines! My 330 trailboss has them and about a year ago i was riding and next thing i knew the quad sounded terrible and wanted to shut down. id got off looked and all i saw was the oil line off. opened up the dipstick and tons of smoke came out. that cost me about 1000 to repair. new crank,piston,rings,connecting rod,wrist pin and everything. but i actually brought it home before i repaired it and put the oil line and new oil in it and it did drive almost the same but the engine sounded terrible like it had nails in it and then it didnt want to go as fast as it went, it would bog out after about half throttle. i wouldnt worry too much about it along as it sounds okay and drives good. if your really worried do a compression test and that will help you out.
2002 polaris sportsman 700 twin 4x4-rear cargo box
-freshly rebuilt top end
2003 polaris trailboss 330 2x4-freshly rebuilt engine
1987 Yamaha Banshee 350 twin (sold)
1998 Yamaha badger 80 (sold)
1993 arctic cat 550 ext! (snowmobile)