I get this strange sound like something is loose in the tranny when I'm coasting to a stop. The sound usually starts at around 5k rpm and will stop at around 2k rpm. Happens in all gears. Noise goes away when in neutral. It's been like this for a while. Recently changed front and rear sprockets with new chain. I've looked for anything that could have been loose or out of the ordinary but everything looks ok to me. Any ideas? Thanks.

 

You stated the bike is making a strange noise, but you forget to describe what the noise sounds like. If you can describe the noise, you will get some better responses.

If its a whining noise, check to make sure you have enough slack in the chain. If the chain is too tight, it will put stress on the output shaft bearing and the bearing will whine. If its a clunking noise, check the front sprocket and make sure its tight. Might also be a good time to remove the sprocket cover and make sure you don't have any witness marks from the chain. Also, check the rear wheel alignment. If its too far off, it could cause the chain to resonate some noise.