i bought a 400ex figured it needed a new top end. did a compression test it only has 30 for compression. i put a tiny amount of oil into the cylinder. did nothing put more into it. it went up to like 60 70. so i started taking it about. i ended up finding out it has paper stuffed into the intake boot before the valves. put it back together still 30. the pin for the depression valve it still there. and goes up and down fine. the cylinder wall looks good. the piston looks pretty good. could it have 30 for compression with the burned out rings i noticed the first ring stayed compressed the 2nd one wasn't. im pretty sure it has the stock piston in it. its like a kyb or something. the timing is good. all the marks lined up. so if its posible to has 30 for compression with burned rings. or is it off timing like its trying to get compression of the wrong one. i read online that the lobes for the cam has to be facing down and they were. any help would greatly be appreciated thanks. its also a 2001 if that matters. im almost thinking its the valves but whats wrong with the valves im not sure about. cuz when i put my hand on the exhaust i noticed it push out but not much but sucked back in. but idk if that had to do with the intake being stuffed with paper.