I have a recently rebuilt evo, with maybe 200 miles on it. On a recent ride, the bike stopped running. Upon trying to restart it, it started back firing through the carb. It never actually started though, just coughed and died. After trailering it home I took a closer look. I suspected timing so I opened up the nosecone and found that the timing might have changed. The screws were loose. Not having a timing light, I moved the timing plate a little in each direction. Still didnt start. Then I noticed something a little more disturbing. I took off the air cleaner cover and turned the motor over with the spark plug wires disconnected. As it turned over there is a rythmic puff of "air" coming from the carburetor. I am begining to think of a collapsed lifter? Should I pull off the pushrod tube covers and watch the lifters? I know when it was rebuilt that adjustable pushrods were installed. (for whaht thats worth) Any suggestions???? Thanks in advance