"Clattering" noise

[Guest]

No better way to describe it. The Flame! has, of late, made a clattering noise when first started. This has happened on 2-3 occasions (out of many tens of starts so far this season). Best way to describe it is that the normal sewing-machine engine sound is replaced with an old-fashioned manual typewriter sound. After 2-3 minutes of operation, the sound abruptly stops (i.e., doesn't fade out).

It only happens on start-up, never happens after the engine is running normally.

Any thoughts/suggestions welcome!

[Mekanix]

Timing chain tensioner.

[tom203]

Can you isolate noise? from valve area or maybe camchain tensioner ? Is this always from cold start?

[MisterCinders]

Location is key here. I had a little clatter from the front that made me fear the valves were in trouble. Turned out that one of my exhaust bolts was a bit loose and allowed the header flange to rattle from time to time.

[yoshisakan]

take off your oil cap while the motor is running, can you hear it from in there? Could be the clutch sleeve hub nut.

[MAC10]

If you start it while it is on the side stand, could be the clutch springs rattling as the oil is tipped away from them. It will stop when the bike is level.

[Kerry]

Thanks for the suggestions. I was thinking cam chain tensioner as well, but the short-lived and very intermittent nature of the noise had me wondering.

@tom203: has happened on both hot and cold starts, but only on start-up.

@MAC10: has happened on both sidestand and level starts.

@yoshisakan: will check next time it happens.

[tom203]

At next start up, put your hand on tensioner knob as you start it up.

[Mekanix]

Return spring is probably weak.

While your there, if its not the spring that's weak, Try loosening the locknut on the other side and see how many turns it takes to bottom out. It should be half a turn but if its worn or that set screw is in slightly too far it could wear into the pushrod and catch it.

that stops the plunger from extending all the way and only the vibrations from the engine free it up.

[JimmyR]

I had an alarming rattle recently. It turned out to be a loose license plate screw.

Sounds to me like a cam chain. But I'm no expert. It can't hurt to go around the bike checking how tight all the bolts are. As a Harley rider this is normal practise for me.

[cowboyup3371]

I had an alarming rattle recently. It turned out to be a loose license plate screw.

Sounds to me like a cam chain. But I'm no expert. It can't hurt to go around the bike checking how tight all the bolts are. As a Harley rider this is normal practise for me.

Agreed. I recently had an irritating rattle coming from the front end. Turned out it was the front brake handle since once I replaced the MC with one from a Kawasaki, the rattling stopped.

[sedelen]

I vote for the cam chain tensioner, it could be dry on start up until the oil gets pumping, but a couple of minutes is rather long. I would think you'd be able to feel the roughness if you held on to it during start up.