Here's the deal. I have the 6 row Jagg and it's mounted on the downtube above the filter. Each fkg time I start this thing its' quiet on the lifters and going down the street, and considerable time after that I can hear the them clatter some. Ride long enough and they get quiet, Idle to rev limit.
Is it possible that with being so high in mounting that some drain back occurs and creates an air space at the top of the cooler. This in turn gets pumped into the engine causing the lifters to get some air and go nuts until it works itself out?
Ron

 

A drop in oil pressure will definitely cause clattering in your valvetrain. I would check to make sure you have no restrictions in your new setup.
Do you have an oil pressure gage. I would change the location or remove it all together to verify if this is the problem

 

Oil pressure is good. Using a high quality mechanical gauge .15 hot idle and 35 running over 1500.
Ron

 

I figure there is full oil circulation in a minute max. Except fot a takeapart, then 90 sec.

Maybe as the engine warms up the cilenders get longer first. Thats when the noise is I believe you said. Pushrod clearance opens up.
Then as the whole engine gets hot including the pushrods, which are steel and don't grow as long as the cilender anyway, catches up. Noise goes away.

Could tighter the adjustment if you wanted. This would help during the warmup.

From what I have experienced you can just about run just one or two FLATS above bottomed out and still be OK. Almost solid.

These Hyd lifters, except for a few special ones, are not really working with the Harley TC with HP springs.