Read the quotes stated below on the another forum...which is about the development of the factory HRC RVF750 racer '91 (raced by Doohan/Gardner during 8 hours Suzuka '91). Of course if you are interested in some works RVF history
Quote LarryL
Developments of the 91 NSR 500 focused around Doohan testing a number
of designs as HRC shifted their main push behind the new up and
comer... For some while Doohan had been asking engineers to replicate
the wide power band characteristic of the 90 RVF750 4 stroke endurance
bike, which he and Gardner had used to lead the previous summer's
Suzuka 8 Hours... HRC answer was the 2 stroke equivalent of the the 4
stroke Big Bang... technically speaking all four cylinders fried within 70
degrees to afford the tire more time to hook up...
Quote MCI
"Though it had another purpose throughout the 1980s, Honda's world
title-winning F1 have permitted the Camel Honda team to and Endurance
weapon, the RVF750, has run bikes that are more RVFthan RC30 in the
latterly been developed with a single objective - winning the Suzuka 8
Hours. Since Honda's approved achieving vital corporate goal has been
to import their works 500cc riders for a one-off four-stroke race,
it's not surprising that the RVF has been more and more modelled on
the NSR500 GP racer in chassis terms, while the V4 engine - based on
the RC30 for homologation purposes, but hyper-developed almost without
regard for cost - has come to resemble ever more closely a four-stroke
GP race motor.
This means that the ultimate RVF750 racers, the am/pm sponsored bike
which Eddie Lawson/Satoshi Tsujimoto took to second place in the '93
Suzuka race, and its companion OKI-backed bike ridden to fourth place
by Mick Doohan and Darryl Beattie - are the trickest, costliest, most
potent and most effective round-piston four-stroke road racers ever
built. To contest the eight-hour GP race that is Suzuka, Honda poured
decades of four stroke tuning experience into extracting maximum
performance from the 70 x 48.6mm engine, without sacrificing
reliability. This meant using the motorcycle that Beattie and Wayne
Gardner took to victory in '92, with some extra refinements to Honda's
pet 'throttle linear throttle concept also yielding a further 5bhp.
This was achieved through painstaking work to reduce friction and
reciprocating weight to the minimum, with extensive use of titanium
and ceramic coated components. Much of this technology - also crucial
in saving weight, allowing the RVF to scale an incredible 140kg
half-dry without lights - was directly transferred to the RC45. So was
the RVF's fairing design, incorporating carbon-fibre air ducts below
the screen to feed the airbox around the carbs, in which the underside
of the fuel tank plays a critical part. Thanks to the restrictions on
bodywork shape imposed by Superbike rules. Honda could do what the
Rumi team wanted to but couldn't, with the result that the
ultra-trick, ultra-expensive 40mm flatslide Keihin carbs breathe from
a pressurised airbox as is now the norm in top-level racebikes of any
type. The right rear Keihin has a sensor which monitors throttle
position for the Programmed Ignition Control (PIC) system. This
employs a microprocessor to monitor this sensor and one in the tacho
to vary the digital ignition between anyone of the five curves, and is
a key element in retaining the smooth power delivery and flat torque
curve the Y4 motor has always been famous for, in spite of the radical
valve timing now required to obtain 'over 150bhp' (believed to be
157bhp at the gearbox) at 14,000rpm from a nominally production-based
750cc engine. One can only speculate about the useof titanium, but for
sure the conrods, valves, seats, retainers and springs would be made
from it, while the camshafts have two-gear cam drive to reduce weight
and friction. Yet, because of the standard-engine-castings Fl rule,
all this trickery is concealed from view: externally, the RVF motor
looks innocuously similar to the RC30 engine. But it isn't. Nor is the
chassis - but this time you can tell, not only by looking at it, but
just by sitting on the bike. The motor is fitted to a meaty,
fabricated alloy frame using triple box extrusions for the twin spars
and essentially identical to the '92 race-winning frame. The spars are
thicker and deeper than on the RC30,and the engine is fitted much
further forward. To help deliver the GP feeling that their riders
wanted, Honda produced steering geometry befitting an NSR500
four-stroke clone, with that steep 22 head angle, a 55/45 frontal
weight bias, a 1,385mm wheelbase and 98mm of trail that was lengthened
via the offsets to give Eddie Lawson the extra high-speed stability
round fast turns he's always preferred. Honda's dynasty of central
cam-drive V4 four-strokes reached its ultimate technical expression
with the '93 RVF.Too bad it didn't achieve its objective with oil left
by another bike sending Lawson into the sand and Kawasaki into victory
lane. But as the rolling testbed for the RC45, it had more than served
its purpose."
god they sound fookin amazing
I wonder why honda dont make another supersport V4.
It is about time that the great from Japan needs to produce and release a new litre bike V4 and if possible a little V4 with minimal 400 up to 600cc. I reckon the competition will if they don't. Their current new bikes (700cc) are indeed economical but their taste is not my cup of tea...i.e. boring, boring 
