To find out more
about the VFR750FJ and FK To find out more about the VFR400 The Honda VFR750F Story
Honda first used a V4 engine layout for their 750 race bikes in the 1970s in pursuit of a four stroke GP machine which could compete with two stroke opposition. This development path resulted in the 1983 oval piston NR500 V4 which produced 135bhp at 18,500rpm.
Honda believed that the V4 layout provided a number of benefits over the then currently fashionable 4-in-line layout. In addition to giving an engine with better torque characteristics the V4 layout produced a narrower engine block which resulted in a narrower, and hence more aerodynamic, bike. However the first production V4, the 1982 VF750S (or Sabre in the US) used a water cooled 78bhp V4 engine in an unfaired bike with the V4 motor connected to a shaft drive - hardly a race replica.
Unlike the gear driven cams on the NR the VF750 used more conventional camchains and the race bike bucket and shim tappets were forsaken for more conventional threaded adjusters though with a single cam follower operating two valves with individual adjusters. The bike was more of a Honda demonstration of technology than a race bike and with a considerable price premium over other (more conventional) 750s was not a big seller.
Race development continued using bored out versions of the production engine including the 1,024cc FWS100 commonly referred to as the Water Whale.
Clearly however Honda had merely been cautious with the radical V4 development and the following year launched the VF750F (or Interceptor in the US). This used the same V4 engine layout in a more sporting rectangular section double cradle frame. The power was increased to 83bhp and the shaft drive dropped in favour of a conventional chain layout. This was the first of a family of bikes comprising the VF400F, VF500F, VF750F and VF1000F.
Race development continued with machines that appeared to share the VF750F's engine but were actually equipped with gear driven cams and shim under bucket valve gear. This coupled with titanium conrods resulted in machine capable of almost 120bhp in race trim.
All of this new development by Honda came seriously unstuck when it soon after the launch it became clear that all of the VF series road bikes, but especially the VF750F suffered cam problems. The problems were much more evident in Europe where riders rode their machines much harder, Honda even sent a team to Europe to find out why machines which were apparently reliable in the USA were failing in Europe.
Honda threw all of their research efforts into solving the problems and solutions included special tappet adjusting tools to oil additives and an instruction for extended warming up period before the bike was ridden.
While still trying to resolve this problem Honda launched the race replica VF1000R a V4 but with gear driven cams. Honda had been using gear driven cams in race bikes from the early sixties to achieve the very high rev limits needed for race bikes but had never before used the configuration in a mass production machine.
Race development continued with the RS series of V4 leading ultimately to the first of the legendary works RVF750s in 1985 with the hallmark single sided layout being adopted later that year.
With a real showroom crisis on it's hands in the camchain problem of the VF750F Honda needed a new bike in the 750 class, it had to be available very quickly but Honda could not be another failure.
Unable to develop a new totally new bike in the timescale Honda turned to its racing department HRC and developed a road going version of the RVF750.
The VFR750F was launched in 1986 as the VFR750FG. It retained the gear driven cam arrangement of the RVF but used short pivoted actuating rockers with screw adjusters; in place of shims. The conrods were steel in place of titanium and the engine cases aluminium instead of magnesium. It however retained the RVFs 360degree layout replacing the 180degree format used in the VF750.
The new engine produced; a vastly improved 100bhp and revved to an almost unheard of 11,000 red line. Around the world bike magazines voted it "Bike of the Year" - the VFR legend was born.
Development continued of the RVF leading ultimately to the launch in 1987 of the RC30 a bike that even that dominated endurance racing for the next ten years.
To find out more
about the VFR750FJ and FK To find out more about the VFR400