Hi everyone,

First post on this site, with my first bike, a '93 GS500E. Bike was running good, then started to have backfire in the exhaust when down shifting/rpms spiked and were coming down. Now is making a weird intermittent ping/pop from the engine when in neutral giving it some revs, as well as the popping in the exhaust. Also isn't idling smoothly. The noises don't happen when idling,just runs rough, but when I give it throttle it will make the random pings, one every about 10 seconds, and when I drop the rpms the exhaust has the backfire. Doesn't sound like a know, and isn't consistent. so Got new spark plugs to see if it made a difference, and was the same. Pulled off the tank and checked the carbs and airbox, seemed normal, carbs were clean. Pretty new to motorcycles, so don't know a ton, any suggestions or comments would be awesome! 

Interesting. Ill keep checking to see if anyone has an answer too!

When was a valve check last done?

Just checked the valve clearances while I had the tank off, left cylinder valves where both in spec(intake .03mm, exhaust .08mm), right cylinder intake was less than .038, which was my smallest gauge, exhaust was .1 mm, would that make these kind of noises in the engine?