I have an 89 Intruder 750 with just over 18,000 mi on it which i´ve owned for nearly two years. About six months ago, the motor began making a metallic rattling sound after it had run for a while and warmed up (like 10-15 mins). Now the rattle starts in under 2 mins after the bike is started. The rattle also becomes faster as the RPMs increase. I took it to a Suzuki dealership and was told the noise was a loose baffle in the exhaust pipe, not too sure about that. I´ve also been told it was caused by pre-ignition. I think the noise is comming from the front cylender because it isnt running as smoothly as the rear cylender. Any ideas about what this might be and how to check for it without going to a mechanic? Thanks!