After being through two sets of stock oem ACCTs in 25,000 miles, I can't recommend anything but the TOC manual tensioners. They just plain work, and have been working for 45,000 miles. The spring on the ACCTs really has very little to do with how they are supposed to work. It puts a small amount of tension on the plunger, so it can advance when the chain wears. But it in no way is designed to hold tension on the plunger so it can't back out, the idea behind the use of stronger springs. The plunger must be mechanically locked, so it CANNOT back out no matter what in order for the tensioners to work. When the tensioner is new, the threads are tight enough to do this. But those tensioner internals vibrate like crazy while the engine is running, and the threads quickly wear and become loose. That is when the plunger starts to back out. You can reset it using the "Grambo trick" but it won't stay reset for long, till it backs out again. You can even advance the plunger manually by turning the screw counterclockwise, and stop the noise temporarily, but just like with the Grambo trick, the plunger will back out after a couple hundred miles. The oem ACCTs are a defective design, though they should last a lot longer if made of metal that didn't wear so easily. No matter what you do to them, you will continue to have problems, and all the time the cam chain is making noise, it is sustaining excessive wear. Use of manual tensioners will permanently stop the noise and excessive wear. In the 45,000 miles I have had them, I have not had to adjust them once, after two initial adjustments, getting a feel for just how tight they should be without putting excessive force on the cam chain guide. The noise has never returned. Just my opinion, but I feel this is the best investment you can make for a Vulcan 750. It permanently solves one of the Vulcan's 2 biggest problems, the other being the spline issue, but if yours are good, keep them lubed with moly paste, and they will stay good.
Even BMW messed up on the driveshaft design, and their splines will wear just as fast as the Vulcan's if not constantly maintained. But at least they lubricated theirs at the factory. Ideally a driveshaft should not require any maintenance, other than changing the gear oil. The splines should be lubricated by gear and engine oil, just like they are on a car driveshaft. But then I think motorcycles should have controlled output alternators as well, just like cars, rather than constant output stators, which run wide open at full output all the time, and any excess current must be disposed of by shorting it to ground. I'm fairly certain this design has resulted in the demise of a lot of stators and R/Rs. And while I' on a rant, I also think all street motorcycles should be REQUIRED to have tubeless tires, in order to meet DOT safety requirements. If DOT is going to exist, they should do their job. It was DOT after all that mandated all motorcycles use their headlights 24 hours a day, which actually seemed to work until cars started doing it too, then they just blended into the sea of lights. But to me, the idea of a "modern" motorcycle, with EFI and ABS, still using tube type tires is absolutely ridiculous.
I am a motorcyclist, NOT a biker.
1997 Vulcan 750, purchased about a week ago
2006 Sportster 1200 Low
2013 Royal Enfield Bullet 500, converted to carb
2001 Yamaha XT225, heavily modified
2004 Honda Rebel 250
1979 Vespa P200E
2002 Vulcan 750 parts bike
1994 Yamaha XT225 parts bike