Is this posible?

[ICANTD55]

I have a very faint metallic noise at idle.
I have clayed the pistons and had plenty of clearance
Both to pistons and valve to valve.
Checked the cover bolts, checked spring clearance, checked cover clearance.
Checked rocker clearance. Put a boar scope in cylinder no witness marks.
I pulled every pushrod tube and clearance them to over .600 Just in case.Running Smith Bros tapered pushrods.You cannot hear it running down the road or above  1100 rpms. Just at idle. I have tracked the noise to the rear exhaust port Where the Acrs dump. With stethoscope on rear exhaust flange I can hear it best. The bike is running very well with no sigh of a problem.
At first I thought it may be piston slap, but I'm not sold on that.
I have a theory
But am wondering if anyone has had something similar happen.
I am thinking the rear Acr is becoming overwhelmed on the intake stroke pulling it down
And overcoming the spring pressure in the acr and then it is slamming back closed.
Now I pulled the power wire to the starter and listened to what the acrs sound like by cycling them and it is very similar to the sound of them closing. Ting!
The Acrs are new but that dosent mean the spring in the acr is 100 percent.
As I said it is faint and you have to pay attention to hear it.

New build
124 S&S
SE 110 heads with ACRs
S&S 625 cams

Anybody heard something like this??   

[Ohio HD]

Don't see it being an ACR. With the intake valve open, there is plenty of draw coming through there, no reason it would disturb the ACR. Sure that you don't have a piston pecking the head? Check the rod for up and down looseness when assembling? Valve spring hitting coil bind? I realize you said 0.6" lift, but springs could be setup too tight. Small head gasket leak?

Get a stethoscope and listen to try and locate where it is.

[ICANTD55]

You got me thinking Ohio the pop up dome is 5.2 cc.  I gave the the guys that did the head work the pistons and jugs so they could fit the chamber to the pistons. But I did not clay the dome area. 
I can fish some solder in there and check though. Good thought. Will go back in with the boar scope first chance.
Thanks

but when I clayed the valve pockets I used Just one piece of a MLS head gasket that I keep for checking.
So not much gasket just the outer layer of a .030 gasket. Rolled over by hand with no noise or bind.
But good thought and I will be checking that
Thanks

As far as rods, wrist pins all seemed tight.

[rbabos]

I have a very faint metallic noise at idle.
I have clayed the pistons and had plenty of clearance
Both to pistons and valve to valve.
Checked the cover bolts, checked spring clearance, checked cover clearance.
Checked rocker clearance. Put a boar scope in cylinder no witness marks.
I pulled every pushrod tube and clearance them to over .600 Just in case.Running Smith Bros tapered pushrods.You cannot hear it running down the road or above  1100 rpms. Just at idle. I have tracked the noise to the rear exhaust port Where the Acrs dump. With stethoscope on rear exhaust flange I can hear it best. The bike is running very well with no sigh of a problem.
At first I thought it may be piston slap, but I'm not sold on that.
I have a theory
But am wondering if anyone has had something similar happen.
I am thinking the rear Acr is becoming overwhelmed on the intake stroke pulling it down
And overcoming the spring pressure in the acr and then it is slamming back closed.
Now I pulled the power wire to the starter and listened to what the acrs sound like by cycling them and it is very similar to the sound of them closing. Ting!
The Acrs are new but that dosent mean the spring in the acr is 100 percent.
As I said it is faint and you have to pay attention to hear it.

New build
124 S&S
SE 110 heads with ACRs
S&S 625 cams

Anybody heard something like this??   

If this was happening it would be pulling a lower vacumn in the intake than normal. If the vacumn is higher at 1100-1200 than idle, you might be onto something.
Ron

[ICANTD55]

I was thinking of keeping an eye on the rear plug to see if it seems leaner than the front . with a carb usally richer on the rear. At least mine has been .

[bwdogman]

Check heat shield maybe

[ICANTD55]

Went back in with boar scope and was convinced it wasn't coming for anywhere internal. So put on welding gloves. And started grabbing differant areas of the pipe. With downforce on the rear header I could get it quiet.
This is the third set of exhaust gaskets, Tried copper , SE, and the wire wound gaskets. I think that the angle of the fitment is a little off because of the progressive link I have to keep the pipe pulled out a smidgen.
I may try to file fit the pipe to the port. But just gonna try a set of the stock gaskets first, Don't like using them but they may be thick enough to make the seal. Boarzilla.
So it is not the ACR, and doesn't appear to be anything major.
It still could be a head gasket but checked seal with the boar scope no sighn of oil or a leak.
Exhaust Gasket first. Odd have had exhaust leaks before but never sounded like this. 

[ICANTD55]

Don't see it being an ACR. With the intake valve open, there is plenty of draw coming through there, no reason it would disturb the ACR. Sure that you don't have a piston pecking the head? Check the rod for up and down looseness when assembling? Valve spring hitting coil bind? I realize you said 0.6" lift, but springs could be setup too tight. Small head gasket leak?

Get a stethoscope and listen to try and locate where it is.

I think your rite will find out tomorrow. I finally got a compression guage adaptor. My low compression build turned into aa 215 ccp build. WTF. I have been going in with a boar scope and looking every time I got back from a ride. I see one spot on the rear piston that is staying clean. Next to the rear exhaust valve relif  on a spot of the dome rite where I would hear it at the exhaust port. So sence I have a lot more compression than I figured and that noise I am taring down tomorrow. To find some answers.

[ICANTD55]

Well didnt find anything on the head no marks. Heads cced 101cc.