Six-cylinder bikes are not designed with practicality in mind: they’re expensive to engineer and manufacture, present significant packaging issues whether inline or vee engines, are often very thirsty, and difficult to maintain. But as a statement, as a flagship model, as a simple finger [middle or otherwise] in the face of your competition, they can’t be beat.
The Benelli Sei first appeared in 1972 as a 750cc machine, with a 900cc version following in 1978. The Sei was developed while Benelli was owned by Alejandro De Tomaso [of Pantera and Maserati fame] as a statement of bold intent to the Big Three Japanese manufacturers that his firm could compete with them in terms of engineering ability, although the Sei was relatively unexceptional in most regards, excepting its spectacularly smooth and exotic motor.
The 750cc version made about 71hp and was capable of 126mph, but it was heavy and expensive, with limited cornering clearance.
From the original eBay listing: 1978 Benelli 750 Sei for Sale
This is a 1978 Benelli 750 sei. 100% original, 100% complete (only missing one reflector on the front right signal housing) Showing only 4323 miles on the odometer. Bike had been sitting for many years. Got some fresh fuel to the carbs and it wants to run, though only on choke. This bike will need to be gone through. Electric start and lights/switches/signals work as they should. Gauge cluster is cracked at mounts. Brakes work, rotors have some rust but will clean up fine. Tires are original Perrelli and will need to be replaced. Most of the chrome has pitting, some rather deep. Fenders are real clean. Pipes are all very solid with some pitting, heavy on lower left pipe. Front spokes have some rust. Paint is all original and in very nice condition but not perfect, NO dents or dings. Inside of fuel tank has some rust, still very usable but will need a good cleaning. Seat is very nice. Tool tray under seat has a small piece broken from it. Overall this bike is in good original condition. It would be perfect for a full restoration as all the parts are there. Or, go through it, clean it up, and have an original rider.
Here’s a good clip of a Sei running, to give you an idea what these Benellis can sound like when set up properly.
This particular machine needs some work, but it seems like work worth doing: the bike appears to be complete and very original. I’m sure the carbs will require some pretty serious money and/or time to put right, but this looks like it could easily become a nice rolling restoration.
There’s definitely a Benelli Sei in my fantasy garage, so I’ll be watching this auction to see where it ends up.