Rattling noise during deceleration

[cpaiin]

Really informative title, right?  So it's difficult for me to be more specific, but I'm wondering if anyone here could point me in the right direction.
Basically,  whenever I'm not pulling the throttle, there's an unsettling rattle as if something has come loose around the location of the engine.  I'm not sure if it's the transmission, crankshaft, or something else.  I thought I would be a good idea to come here and see if anyone has any ideas on what could be wrong before I tear the thing apart and wind up in over my head.

Again, it only occurs when I'm decelerating.  It occurs no matter what gear I'm in (including neutral).  The sound is only audible above ~20mph.  Once I decelerate below 20mph, the sound dies off. 

Thanks for any suggestions.

[Thrillwill352]

Unfortunately I don't have any advice but I am experiencing a similar problem but mine specifically happens at about 2.5-4k rpm's

[06_500F]

Cam chain? Tensioner might not be working correctly?

[Big Rich]

First things first, check your drive chain tension. When accelerating, the motor is pulling the top half of the chain which pulls the wheel / sprocket. But when decelerating, the wheel is pulling the bottom half of the chain while the top half goes a little slack. If your swingarm rubber / protective guard is worn out on the top half, the chain could be sliding on the swinger.

[gsJack]

While your checking the drive chain take  a look at the front sprocket.  A badly worn front sprocket will make a rattling noise on decal at lower bike speeds as the chain clicks off the worn hooked teeth.  Doesn't do it under power.

[cpaiin]

How the simple things escape me.
Looks like all I had to do was tighten the chain. Thanks for the tips everyone.