Skight knocking / tapping sound at idle

Its weird I have a knocking sound coming from the front lower crankcase only when at idle. after it is warmed up itas not as loud and once i hit the throttle it goes away completely. The bike runs and idles perfectly for its age and the sound has always been there, (8 yrs fyi). Carbs are thned and synced, Valves are right. Just figured id ask.

 

Does it go away when you pull your clutch in?Might just be clutch rattle.

 

my money is on a cam chain.
has the cam tensioner adjustment been performed?

 

If it's a 550 and depending on the age and mileage, it could be that the primary chain tensioner/guide has broken up and the Hyvo chain is flapping around.
I think it was only an issue on the early ones (not sure about that though) and only showed at high mileage. Unless the HYVO chains are cheaper now, or the engine has sentimental value I wouldn't bother tearing it apart.
If it is the problem, then taking the sump off will reveal some lumps of black rubber. At the time I did the work on mine I was told it was common at 80-90,000 miles - or maybe that was how long the chain would last. I've never heard of one failing catastrophically, though.

 

I had a "Knock" that turned-out to be a leaking Exhaust Header Gasket.

If you DO have a knock ... it's best to try and find it!

A wooden or fiberglass dowel of about a Meter in length makes a good "Listening" tool.

Hole the Tool in a clenched fist with your thumb over the end. Place the end of the Dowel on to the Engine at various spots and apply pressure to the Rod with your thumb.

Place your ear to your thumbnail and listen for the sounds that the engine is making. Probe around the area you think you hear knocking.

You'll definitely HEAR a KNOCK.
You won't necessarily HEAR an exhaust leak or anything other than routing mechanical and rotational sounds if the Engine is not knocking.

Probe the crankcase and disconnect one sparkplug at a time to see it the knock is a Big End or wristpin.

The Knock will go away when the offending Cylinders has no spark.
This is Old School.

If you spun a bearing or have loose tolerances at a bearing you'll hear it.

If you hear a regular tapping noise neat the cam shafts its most likely a loose valve and loose valves can't burn.

Some noises are good noises!!!