Maybe you guys can help me out.
You guys seem to know more about engines than most on TT, so I'll ask here as well as TT. My 05 DRZ400 is making a strange ticking noise that I don't believe is the valves or cam chain. The bike doesn't make a ticking sound at idle, under acceleration, or cruising. It only makes the sound during engine braking. If I pull in the clutch, the sound stops.
The tick itself isn't normal. It sounds like a metallic heartbeat. Again, only on decel engine breaking: tick tick -- tick tick -- tick tick. The sound doesn't really seem to be related to engine rpm as the the speed of the tick only marginally slows down, almost not even noticeable in time.
Do you guys have any ideas? The noise came on suddenly, it didn't grow louder as time went on, it was just there one day.