engine knocking

[boxer04]

I dropped my bike about 2 weeks ago while changing the oil (don't ask).  Now when ever I start the bike it makes a knocking noise for a couple of seconds, then stops.  It only does it when the engines hot.  When I start it cold in the morning, it won't do it.  It will also do it when I stop at a light or something, and the engine comes down to idle.  I thought maybe I fouled a plug, so I change them both out and it still does it.  Can someone help me out.

[JamesG]

Does your bike have case guards on it?
Which side did it fall on?
Easiest/cheapest thing to check will be to go around the bike looking for things that could have broken or come loose like an engine mount or the exhaust hanger (why I asked which side).

Alot of times a broken or loose bit will has a specific "sympathetic vibration" range where it will be quiet most of the time, but at a specific rev range of the motor will shake and make noise.

After that we start worrying about inside the motor, which gets unplesant & expensive fast...

[boxer04]

Didn't need to hear that about expensive.  It fell on the left side, so no problems with the exaust hangers.  and I checked the motor mounts and they're all good too.  when I dropped it, it took most of the force on the handle bar (shifted it about an inch to the right) and the clutch lever (bent the end of it a little).  It barley touched the engine, just a little scratch on the bottom of the left engine cover, and a some scuffs to the fairings.

[JamesG]

donno  :dunno:

Is it a metallic noise or like a knock on a door  thumping sound?

[MarkusN]

Could be just axial camshaft play, which is more annoying than harmful.

By knocking it over you had the camshaft hit one extreme axial position, out of which it moved with some knocking sounds.

Now that you are aware of this you hear it also when it happens at other occasions.

Or the new oil washed some deposits out, so the camshaft can knock more audibly.

Can you locate the sound? And characterize it better? (metallic? hard? regular, when it comes, or completetly random?)