Brian Gillen, MV Agusta’s three- and four-cylinder platform manager, explains the primary difference between the F3 675 and 800: “On the 800 you’re talking about 148 hp (at the crankshaft) versus 129 hp. So the 800 has just about the same horsepower as our F3 675 World Supersport racebike, but you have more torque than on the World Supersport bike and the same weight as the standard F3 675.” The disparity between engine internals isn’t overly dramatic, of course; the F3 800 has the same bore (79mm) but a longer stroke (54.3mm versus 45.9mm) and, as a result, shorter connecting rods. The camshafts are the same, but, “The valves are all titanium and with the longer stroke we had to slow down piston speeds,” Gillen says. Consequently, the F3 800’s rev limiter has been lowered from 15,000 rpm to 13,500 rpm. Other internal changes include a slipper clutch with 10 plates versus eight, new fuel injectors with a higher flow rate, and pistons that are lighter and also different in regard to crown shape. The compression ratio jumps from 13.0:1 to 13.3:1 as a result.

The F3 800 and 675 share a common chassis and hardware, though the 800’s Marzocchi fork uses a stiffer compression damping stack to compensate for the added braking force provided by new Brembo M4.34a monoblock brake calipers. Similarly, the Sachs shock gets a firmer compression and rebound damping stack. Spring rates are the same front and rear.

A modern sportbike depends heavily on the algorithm within its engine control unit, and here’s where MV Agusta knows that there’s been room for improvement. “Honestly, at MV we really had to take a couple of steps back and reevaluate,” Gillen says. “Because with our experience we pushed really hard to get into production with our F3 675, and we found out that really we were behind the competition with our electronics.” The result of that realization is MV Agusta’s third entirely new algorithm, with calculations intended to shorten the time between input and reaction both at open and closed throttle. In simpler terms, the new algorithm is less cumbersome and therefore able to provide a more formal connection between a rider’s wrist, the engine, and rear wheel. As has been the case in years past, MV Agusta owners can find updates for their bike’s map on the MV Agusta website; if a new map has been released since the last time your bike went in for service, then you can go back to the dealer for a free software update.

Similar to the F3 675, the 800 has Rain, Normal, Sport, and Custom riding modes, the latter of which can be adjusted for things like engine braking control (Normal for more engine braking and Sport for less), gas sensitivity (how fast or slow the throttle reacts), and engine response (how fast the engine spins up). The traction control system gets eight levels of intervention plus off, and in an effort to put more control in the rider’s right hand, MV Agusta has outfitted the 800 with a new throttle return spring that’s flatter. “So the spring is stiffer at the beginning but more constant throughout,” Gillen says. Theoretically, this will make the throttle easier to modulate.

Different Strokes

There are distinct similarities and differences between the F3 675 and 800 at the racetrack. Both bikes are designed around the tightest rider triangle possible, for example, and that makes the F3 800 especially difficult to ride if you’re taller than 6 feet. More to its favor, the F3 800 steers into a corner with the ease and precision of a 250cc sportbike. A sure result of the counter-rotating crankshaft we’ve raved about since the F3 675 was first introduced two years ago.

The engine dynamic between both bikes is noticeably different, and due to the crankshaft’s higher inertia the F3 800 picks up revs just a bit slower than the 675. Midrange performance is a step above, and we’d quickly discover that on the 800 it’s easier to run a gear higher and tractor out of the corner, whereas on the 675 you’ll have to keep the engine spun up consistently. Acclimating yourself to the 1,500-rpm-lower rev limiter takes time but mostly because MV was too stubborn (cheap?) to update the 800’s digital display; the bike’s 13,500-rpm rev limiter appears about an inch to the left of where the rpm display ends, and the numerals are so small that you’ll almost never be able to read them. Power delivery isn’t perfectly linear, but there’s never that uncontrollable push like you get on the 675 as you reach the top part of the revs.

 

SPECIFICATIONS
2014 MV AGUSTA F3 800
MSRP: $15,798
ENGINE
Type: Liquid-cooled, DOHC, inline-triple four-stroke, 4 valves/cyl.
Displacement: 798cc
Bore x stroke: 79.0 x 54.3mm
Compression ratio: 13.3:1
Induction: Mikuni EFI, 50mm throttle bodies, dual injectors/cyl.
CHASSIS
Front tire: 120/70ZR-17 Pirelli Diablo Rosso Corsa
Rear tire: 180/55ZR-17 Pirelli Diablo Rosso Corsa
Rake/trail: 23.6°/3.9 in. (99mm)
Wheelbase: 54.3 in. (1380mm)
Seat height: 31.7 in. (805mm)
Fuel capacity: 4.4 gal. (16.5L)
Claimed dry weight: 382 lb. (173kg)