Originally Posted by RIPSAW

You are speaking about the first year or so of the TC. Harleys' engineers put the oil injectors in at the base of the cylinders for oil cooling of the high heat area at the top of the pistons.

Problem is, at a street light, with no air flow, it was found out the hard way a V-twin can on the short term can take more heat then engine oil.

So the redesigned the oil injectors with 15-18 psi release springs and engineered the oil pump thru design so flow pressure was about 12 psi with 50W oil and their 5 micron oil filter. Unlike big long engines, Harleys' don't need a lot of pressure to get oil all the way thru. Oil film lubricates. Not pressure.

Above idle, it can easily top 35, so there is a relief valve in the cam plate so the underside is not totally flooded.

Those injectors also add lubrication for the inner cam bearings along with the limited splash from the crank wheels.

Older Harleys' are not 100% dry sump. Especially the TCb models. In the bottom of the block where the oil pickup for the return side of the pump that is in the cam galley. There is about a 1 1/2" raised wall.

That keeps about 1/2 quart of oil in the sump. Best I can tell when I have drained the cam plate side there is another 1/2 quart there.

Later Harleys' designs does not use that. Probably to pick up a few horsepower.

Not sure what noise you are referring to. OEM cams have a few thousands of and inch rise on the base circle just before big lift starts to be quite and compensate for lifter bleed. Most high performance aftermarket does not.

Lifters must bleed some or they would make the valves leak.