Metallic clunk from engine 6-8 seconds after starting

[jogirob]

Hello all,
Anyone else getting a metallic clunk from the engine 6-8 seconds after starting? I can hear it coming from the front of the engine and can hear it affecting the RPM and can see it in the RPM gauge. After the clunk RPM's get slightly higher and sounds smoother. I've noticed the clunk steadily getting louder as the months go by.

I'm at about 1,250 miles and I did the valve adjustment at the factory recommended mile mark. The bike sometimes dies when I coast to a stop and I blip the throttle from idle but very rarely.

About time for another valve adjustment?

[fjmartin]

Can't comment on the clunk but when my bike was new and the valves started to close up the bike would die when releasing the throttle and doing the valves would resolve it. My intakes settled in at about 1500 miles but it took till 13000 before the exhausts settled in and stopped moving. At the start I was doing valve checks/adjusts at 500, 1000, 1500, 2500, 3500, 5000, 7000, 9000, 11000 and then 13000. Now I am going to switch to 5k intervals since they have settled.

[Inroads]

Originally Posted by jogirob

Hello all,
Anyone else getting a metallic clunk from the engine 6-8 seconds after starting? I can hear it coming from the front of the engine and can hear it affecting the RPM and can see it in the RPM gauge. After the clunk RPM's get slightly higher and sounds smoother. I've noticed the clunk steadily getting louder as the months go by.

I'm at about 1,250 miles and I did the valve adjustment at the factory recommended mile mark. The bike sometimes dies when I coast to a stop and I blip the throttle from idle but very rarely.

About time for another valve adjustment?

Did "clunk" show up right after your valve adjust?
Maybe better define the clunk and does it go away after warm up or accel/decel ??

[Jay In Milpitas]

Originally Posted by Inroads

Did "clunk" show up right after your valve adjust?
Maybe better define the clunk and does it go away after warm up or accel/decel ??

Agreed, also is the noise consistent, happening every time?

Most likely best to call Gerry at CSC tomorrow.

[ChondaChondaChonda]

Just a thought, but mine occasionally does something similar ; my hunch is that the idle may drop low enough to allow the compression release mechanism to engage and then disengage. Not sure how to test the theory. Perhaps caused by a weak spring or something else, I'm not really sure, but it does kind of make a clunk sound when it happens. My NC250 is not in an RX3.

[jogirob]

It happens only once a few seconds after starting and idling. Calling it a "clunk" would imply something complex. It's more of a metallic plink, like if you'd take your screw driver and plinked it against the engine guard.

One plink about 6-8 seconds after start up. No weird sounds otherwise. Happens every time at start up no matter hot or cold. I did the valve adjustment many months ago but I just really started noticing the plink maybe 1 month and a half ago.

[CSaddict]

Check to see if one of the lock nuts backed themselves out on the adjuster. I've seen that twice.

[jogirob]

OK so if I start the bike in neutral without depressing clutch the plink happens as described. However, if I depress the clutch during start up, and in neutral, the plink is delayed until I release the clutch. About 3-5 seconds after release to be exact.

[ChondaChondaChonda]

Originally Posted by jogirob

OK so if I start the bike in neutral without depressing clutch the plink happens as described. However, if I depress the clutch during start up, and in neutral, the plink is delayed until I release the clutch. About 3-5 seconds after release to be exact.

There is a small amount of clearance between the clutch push rod and the 'plunger' that pushes the outer plate away from the clutches. I wonder if you are hearing that rod get spun and thrust into the gap?