I was given a 2005 Suzuki Quad sport 250 the compression is very low i'm trying mystery oil now to see if maybe rings are stuck or a valve is stuck open. is there anyway of telling which is the problem b4 tearing down engine if oil doesn't work.

 

Leak down test can tell you whether it's leaking past the valves,piston or both.You should be able to hear it leak through the carb if it's mainly the piston,exhaust pipe if it's a valve problem.And again both can leak on a low compression engine. Can even show head and base gasket leaks. If compression is low and valves are adjusted correctly,etc,you still probably will have to pull the top end down and check it out. You can check out the piston and rings,plus you can pour solvent into the intake and exhaust ports to see if the valves either seep or pour out also once the head is off. Small Engine Repair: Using a Harbor Freight Leak-Down Tester on a Briggs & Stratton Engine - YouTube