Can anyone tell me what type of steel the stock retainers are made of? I mean if they are really just pressed steel from the 70s, I can't imagine it is anything to rave about.
Titanium alloys(the pieces we are seeing are likely not pure titanium) will almost always have a higher tensile strength than steel. It is a bit more brittle, but I don't know how hard a valve is shock loading that titanium. If we are worrying about wear as it rubbing against it and wearing in, I'd be amazed to see the old steel pieces wear worse than the modern Titanium pieces.
Steel is a VERY broad word. It could be Chromoly, Stainless, Cold Rolled, Hot Rolled, Heat Treated Carbon Steel, there are a ton of materials the word can cover. And they can be VASTLY different in their strength characteristics.
IF you go off a chart like this:
http://en.wikipedia.org/wiki/Ultimate_tensile_strength Every form of steel is weaker than Titanium save for Chromoly Steel. Which I HIGHLY doubt Honda was producing Chromoly Retainers back in the day.
Also are the retainers we are discussing stamped steel or machined from billet material? Machined pieces will have more material to them in the key areas to make them stronger. And once metal is bent once(like stamping) it is made weaker by the process. Unless treated afterward in some manner it will just be a weakened piece of metal.
A lot of our bikes are probably being put through abuse Honda never intended them to go through.
Personally I've only hit 10,000 RPMs once or twice on my bike. I have no intention of it being a weekend racer. If I want more power it is down low for coming harder out of a corner and a bit of passing power.