Noise from oil filter 1520 f6c

[Woodsyv12]

I've seen this has been discussed before and wondered if it was resolved.
The noise is strongest at the oil filter, I haven't tried replacement yet because I'm waiting for a new filter.
It occurred after removing the engine to paint it. Starter motor, alternator were removed during this. Valve clearances done. Demobbed, Engine replaced and appeared to run as before. Changed oil and filter and ran engine all was good.
Bike sat for a month then I ran it and then this very same noise appeared. Its loud when cold and virtually disappears when hot.
Took water pump out and obviously caught all the oil that came out of the case, so it was almost empty. Ran engine (briefly) and there's no noise.
I thought it was the water pump but after stripping pump and finding nothing I replaced the water pump.
I filled with oil, ran engine and noise returned.
Drained oil and very briefly ran engine again.  No noise.
It appears to either oil filter or oil relief valve.
Anyone had and cured this?
Was this issue solved?

[RonW]

my defective oil pump made a high pitch shrill sound usually when riding though.

[Jess from VA]

Could this be the buzz bolt?  http://www.valkyrieriders.com/shoptalk/buzz.htm

[Woodsyv12]

Could this be the buzz bolt?  http://www.valkyrieriders.com/shoptalk/buzz.htm

Hi chap, If it was the 'buzz bolt' it would still make the noise when oil drained out of the engine. 

[The emperor has no clothes]

Could this be the buzz bolt?  http://www.valkyrieriders.com/shoptalk/buzz.htm

Hi chap, If it was the 'buzz bolt' it would still make the noise when oil drained out of the engine. 

I don’t know if running it with the oil drained is a very good idea. I personally wouldn’t even turn the engine over without oil.

[Jess from VA]

To get all the oil out, to get the whole gallon in, I bump the starter on a drained crankcase a couple times.

But I don't let it start.  Put down a lawn and leaf bag, it shoots out (a little).