the folk lore I heard, for whatever it was worth, is that back in the days of Laverda production the 6,500 limit shown on the round face tacho was for the 750 twins. Then, supposedly the same tachos were used on the triples without changing the rev limit, supposedly for cost of production of reasons. I have no way of knowing how true any of that may be.
the other issue is just how accurate or inacurate an old mechanical tach actually may be, especially with the needle bouncing around as so many of them do. My 79 1200 with 4 C cams routinely sees 8,000 + rpm on the mechanical tach before it hits the rev limiter built into John Wilson's IIS ignition that has been in the bike since (?) 2000 maybe? I see John's post above that the limiter in his ignition is set for 8,250, with that the case my bike has hit the rev limiter in the IIS likely hundreds of times. When I get to sending my 79 1200 tach and speedo to Marcel at CB750faces for full rebuilds, I have already pre arranged with him for a custom tacho face with the redline starting at 7,500 rpm, rather than the stock marking of 6,500. So, for my 79 1200, from the original bad bearing crank batch, with crank rebuilt by Phil Todd way back in the day still with stock rods, I have personally done almost 150,000 kms riding it hard and revving it high.
On the other hand, and to Red's point of rods typically failing at lower rpms, my 1984 RGS then stock engine went bang and bent a rod at roughly 3,500 original MILES (USA spec bike) Not being ridden hard, not being revved high. When I went to rebuild the engine, stock rods were in very short supply, so "while I was at it" the crank was rebuilt with Carillo rods and all new bearings supplied by Wolfgang, a 1200 barrel, and high comp 1200 J&E pistons. That engine now has only about 9,000 miles on it, but is holding up well. I pretty much gave up on the RGS tach years ago, the sucker bounces around like a crazy thing, when I am riding it hard (like track days or keping up with friends on modern high powered bikes)) I just wind it until it doesn't want to keep on pulling anymore. The RGS has a 15 year old Witt ignition in it, don't know if the WItt has a rev limiter built in, or if it does, what the rev limiter might be? Does anyone know?
My 82 1200 TS Mirage Series 2 I rebuilt all stock except the ignition, which is an early hybrid from Red, (don't really even remember the details, seem to remember Sasche/Ignitech). Whatever, does not really matter. That bike, with its stock A11 cams, has so much more torque lower down than my 79 1200 with the 4C's, I never really feel any need to rev it high, totally different character and riding experience.
Your mileage may vary. I am just relating my own experience. Use whatever shift point and red line you are personaly comfortable with, 6,500 rpm should certainly be the safest unless you experience a con rod failure at even lower rpm's as Red references. These are old bikes after all.
