Clearly you have doubts, or why would you be replacing the Vreg?
A year ago I didn't even get my bike out. Having owned it for 26 years It's only missed 2 riding seasons due not having the time and/or money to get it on the road. So when I got it out this year, it needed stuff. It's an old motorcycle. I'm sure all of us here know they ALWAYS need stuff. So over the course of this summer I have been chipping away at the list.
- rebuild front brakes
- rebuild carburetors
- new air filter
- new plugs
- replace throttle cables
- helicoil repair leaky fork leg drain plug
- replace turn indicator relay (which worked most of the time, but would intermittently cut out)
- replace points cover gasket
- replace gas cap gasket
- new clutch cable
- new oil filter bolt
- new tach & speedo cables
I've owned this bike for 26 years and done almost all of the work myself, so I know everything that's wrong with it is on me either due to neglect or, for instance over torquing a fork leg drain plug bolt, but I love this bike and regret having let it slide into disrepair, so I've been plugging away at it as time and funds allow, and so far this summer I've found that if I work on a system, it's probably best to replace what I can, because more than once I started working on something, like the brakes for instance and had to stop because I needed more parts. SO now I'm to the point where most of the mechanical issues are all in hand, and I'm moving onto less pressing issues, like replacing the cracked turn indicator lenses. The charging system has been on my mind all summer, but it's been a low priority, because It's never required me to charge the battery manually, and it just keeps running, but it's the next thing I'm tackling. Less important than good working brakes, and more important than shiny fenders. So I know it needs work, and I figure if I'm going to work on it I might as well replace the 41 year old regulator and rectifier which I know to be something that gets problematic with age, and which I have never touched in the last 26 years. From what I've heard the electronic ones work better than stock. So that seems like a good idea. BUT I've been riding it this way for years, not really knowing it was a problem for a lot of them. I put several thousand miles on it this summer, and it hasn't been particularly problematic in spite of the fact that it is clearly not right. In those miles I've found that it doesn't seem to make a difference wether I go 10 miles and never get above 4000 rpm, or go 50 miles and push it straight to redline. At the end of the ride the battery is still in it's same workable, but sub optimal state. So no I haven't put the voltage meter on it at multiple RMPS, but I've ridden it enough to have a pretty good idea that an extra 1000 rpm for 45 minutes is not gong to make a remarkable difference.
Interesting rationalization, I suppose. But, I'm trying to help you get the charging system back to proper function. All this dancing about the issue isn't fixing the problem statement. And, "a pretty good idea" may work fine in your head. But, it doesn't relay facts about just what is going on with your bike.
"Because it's old", Just might be the poorest reason for replacement. The axles are old. Replace? The carburetors are old. Replace? Restoration isn't about total replacement. It is correcting the bits that actually need it.
I have about 10 of the 41 year old regulators and rectifiers, and they all work just fine. I did adjust and refurbish two of the vregs, because someone tweaked it without knowing what they were doing. They are nearly as reliable as a fender. If you connect it properly, give the right battery voltage status and don't massage it with a sledge hammer, the vreg still does it's job. Yes, I've encountered blown rectifiers. Abuse in the form of reverse polarity connections can damage them. The rectifier junctions, (essentially a rock or sand chip) simply don't degrade with time alone. Usually takes human influence to bring about their demise.
rt's posts are relevant to his charging system, which is likely operating correctly.
I think it's apparent that yours doesn't work like his. But, valid testing has been avoided for reasons I don't fully understand.
Good Luck!