Clunking sound? At startup and before running temp

[agrady1995]

Hey there. 99' honda valkyrie interstate, and recently did total carb rebuild with 6 brand new, air cut valves and the kit from red eye.

I have been recently hearing a clunking sound (not very loud, almost like a loose part) but only occurs whe  engine is first moving. In neutral, sotto g still I hear normal engine idle. Once I out it into first and start to let out the clutch it'll move and also makes a slight clunking sound, and I'm worried that it's something like one of the 6 pistons is loose against the crankshaft... I can try to upload a video of the sound, but is there something I should check?

I do have the pair valve still installed, and will put on a desmog this weekend, but is there anything I should check?
Timing belts are brand new and properly tensioned, that was one of the first things I checked.

I recently did a valve adjustment and only had to touch two, and re-check ed those but they are fine as well.

HELP!   OHH AND 68K MILES

[Challenger]

Is it multiple clunks or just one as you start to move? With engine off and in first gear, rock bike forward and backward to see if you hear the sound. Could be the rear wheel dampers taking up slack.

[John Schmidt]

Check the driveline....drive shaft, u-joint(1st choice), pinion cup....just to mention a couple. Also might be a front caliper causing that sound. Do you get any noise when underway or only when just starting to move. If it's that, my guess is caliper(s).

[shadowmagic]

Can you post a link to the air cut valves? Thank you.

[Bighead]

I had a clunking sound before desmog (until warm) and it went away after. So I think it was the pair valves.

[Rio Wil]

Sounds like the rubber dampeners in the front of the alternator have gotten hard and make a light clunking sound, if I remember right, it is worse at idle and in neutral.

[Jims99]

Could it be a misfire you’re hearing? Maybe one cylinder is running lean at start till it warms up causing a miss. That could cause the clunk noise. Try testing the exhaust temperature. There are a few threads on here about it. Could just need mixture screw adjusted. Hopefully it’s something simple.

[indybobm]

If it does it consistently, try lightly applying the front brake before you start moving.  As John said, it could be the front pads.

[John Schmidt]

If it does it consistently, try lightly applying the front brake before you start moving.  As John said, it could be the front pads.

They're supposed to be "floating calipers" but sometimes after a few years they don't "float" as designed and when you start to move you'll get a clunk. Or, might be the front master cyl. needs a good cleaning, specifically the little hole in the bottom with the little clip covering it. Not allowing pressure release and sometimes causes the clunk.