Don Terrill’s Speed-Talk

Cosworth's 20,000 rpm CA F1 V8 used bronze main bearings, apparently machined from solid.

A lot of bikes are using 4.5 mm stem Ti up to 15000 rpm with absolutely zero issues.

BillK, put the feeler Guage between the journal and bearing or between the cap and bearing? Between the crank and the bearing. I know it looks crude and I cant remember who showed it to me but it is a great way for DIY guys to check for an approximate clearance if they dont have the correct tools. ...

Nitrided.

They were offered as a gimmick retainer machined from Vanadium.

Force, not 'pressure'.

Brent, you're asking a question with the title, not making a statement, so no need for an exclamation mark, let alone three of them.

Run it.
A valve has virtually no tensile load on it at any point except when seated and then it is very low in relation to the stem's cross sectional area.
Open spring force loading is through the top shoulder of the collet groove and the circumferential clamping load the collets apply.

It's facing the wrong way and unfinished underneath.
Pick up the high pressure air from the base of the screen and make a tray.
That location is likely relatively low pressure and high turbulence.

Block and head bulk temperature regulation is handled by the coolant circulation.

Looks like bark on undersized bar stock used that didn't grind clean.

Secular best wishes to David.

Lately I've been testing the KTM Duke 390 as a temporary city ride and track day ride alike. The 390 is a liquid cooled single cylinder of 373cc, with bore and stroke of 89x60, and a four valve DOHC head. From the factory wheel hp is 41 to 43, and wheel torque is 24 to 26. When properly fettled wit...

Make them from bronze.

Make the seats longer/deeper/larger od heavier wall, no question.