The original VFR750F was first introduced to journalists after the 1985 Bol d'Or, and launched at Jerez, Spain. Introduced for 1986 as a complete redesign of the VF700/750F models in order to address some of the camshaft and bearing problems that had become associated with the first-generation Honda V4 engines, and to improve Honda's negative image concerning this engine. Compared to the VF750F, the new VFR750F had greater power output (104 hp up from 83 hp), lighter weight (claimed 20 kg), a lower centre of gravity, a wider front tyre, a slightly shorter wheelbase (15mm) gear driven cams and six rather than five gears.
"Tariff beater"[clarification needed] 700 cc versions (VFR700F) of the first-generation bike were available alongside 750 cc versions in the US market, due to the tax laws in place at the time that penalised large-displacement imported motorcycles (in order to protect the troubled Harley Davidson Motor Company).
In the Japanese domestic market there were other VFR750F variants:
VFR750P - A police-specification model with its own distinctive model number (RC35) was restricted to 77 ps (75 hp) and fitted with a five-speed gearbox, modified main stand, gear indicator, uprated alternator, crash bars, higher handlebars, and modified speedometer. This bike was not offered for sale to the general public.
VFR750K - Not to be confused with the VFR750FK, this bikini faired training version of the VFR750F, again with its own distinctive model number (RC37), was restricted to 77 ps (75 hp). The oil cooler was removed and it was fitted with a modified main stand and gear indicator. This bike was offered for sale to the general public.
A special VFR750F called the '6X', a 135 hp@13000RPM 188 mph full HRC prototype using RVF cycle parts and containing titanium valves, magnesium cases and flat-slide carburettors, weighing 165 kg (364 lb) (dry), even less[peacock term] than the factory RVF that was first seen ridden by Wayne Gardner at a Suzuka test against TT F1 machinery.[clarification needed] Wayne broke his four-stroke lap record by 1.5 seconds. Six examples of the '6X' were built, 4 for the Domestic Championships and two for the American Championships.
In the US Fred Merkel and Wayne Rainey contested the 1986 AMA Camel Pro Championship, which at the time had both Superbike and F1 races but only one championship, with the best finish of the day counting. Merkel just rode in the Superbike while Rainey did the F1 as well. Merkel won two races and Rainey seven, but the championship was won by Merkel by two points.
For 1987 Merkel's bike was passed to Bubba Shobert who took 3rd place in 1987, being beaten by Wayne Rainey and Kevin Schwantz. The points he earned during the 1987 season gained him victory in the AMA Grand National. In 1988 Shobert won three of the seven races to win the AMA superbike championship.
The engine developed in the 6X became the basis for the factory racer, the VFR750R. A race kit was available for the 1986-87 VFR from HRC for US$4,000, this including a titanium exhaust and was known as the VFR750RK.[better source needed]
The VFR750F models all used 748 cc 16-valve gear driven DOHC liquid-cooled 90° V4 engines with carburettor-based air/fuel induction; the bore × stroke remained the same for all 750 models at 70.0 mm × 48.6 mm (2.76 in × 1.91 in). The engine was made of cast aluminium alloy with the crankcase being divided horizontally, VFR750P and VFR750K models use slightly different crankcases with the lower casing being modified to allow for the gear position indicator in place of the neutral switch. On all the VFR750 models the gear drive for the cams was between the cylinders. Lubrication was via a wet sump with a chain-driven, dual-rotor oil pump; an oil (air) cooler was also fitted. The transmission was a 6-speed, with a constant-mesh, wet multi-plate clutch and chain drive to the rear wheel with the exception of the 5-speed VFR750P which had a spacer in place of one of the gears.
The VFR750F uses a 180° crankshaft, instead of the 360° crankshaft used in the VF and VFR750R.
In comparison to the VF750 almost every component had weight shaved off it, each connecting rod lost 90 g (3.2 oz), rocker arms 6 g (0.21 oz), intake valve 0.5 g (0.018 oz), exhaust valves 1.5 g (0.053 oz), pistons 20 g (0.71 oz), piston rings 1.3 g (0.046 oz) per set, valve springs 17 g (0.60 oz) each.
The V4 engine has proven itself highly reliable,[opinion] with few known faults. The gear-driven camshaft system removed any lingering concerns about cam-chain maintenance, which had dogged the VF-series of Honda V4 engines. Valve adjustment on first-generation VFR750Fs was by screw and locknut, which changed in 1990 to shim-under-bucket, along with the valve-clearance inspection interval to 16,000 mi (26,000 km). However, RC36 engines have been known[by whom?] to reach well over 50,000 mi (80,000 km) without any need to adjust the valve clearances.
The 1986 VFR750F used what Honda call a diamond type frame, this is because the engine is "set" in the frame like a precious stone is set in jewellery. This design of frame is now referred to as a twin spar. The 1986 VFR750F frame uses the engine as a stressed member and has a cast aluminium headstock joined via 28 by 60 mm (1.1 by 2.4 in) extrusions to the rear castings. The downtubes are 30 by 40 mm (1.2 by 1.6 in). The VFR750F was the first of the 750 class to have an aluminium twin spar frame, weighing just[peacock term] 14 kg (31 lb) and the nearest thing on the road to the VFR,[opinion] the GSX-R also had an aluminium frame but it was of a conventional twin cradle design.
First-generation VFR750Fs sported anti-dive (adjustable on some models) on the damping-rod front 37 mm (1.5 in) Showa forks (uprated to 41 mm (1.6 in) for 1988) and a conventional, dual-sided aluminium swingarm with a centrally located Showa damping unit with remote hydraulic pre-load adjustment at the rear and a pro-link suspension linkage.
Second-generation models had non-adjustable 41 mm (1.6 in) cartridge-style Showa front forks, coupled with a remotely adjustable (for pre-load) emulsion-type Showa shock absorber and the trademark single-sided swing arm. Honda soon upgraded the VFR750F's suspension to include pre-load adjustment on the forks, and damping adjustment on the shock. The bike's distinctive swing arm,[opinion] derived from the Elf-designed race-bike Pro-Arm development work, has the advantage of allowing rear-wheel removal without the need to remove the drive chain or rear axle, and allows chain adjustment to be made very simply with no concerns of altering wheel alignment.
Third-generation VFR750Fs continued to use the same basic suspension components as the VFR750FN/P, though the single-sided swing arm was redesigned to reduce weight.
The VFR750F can be divided[by whom?] into three distinct generations, with significant revisions having taken place upon the introduction of the VFR750FL in 1990 and the VFR750FR in 1994. The VFR750F ceased production in 1997 with the introduction of the VFR800Fi, marketed in the US as the "Interceptor" and in the UK as the "VFR".
1986–1987 — VFR750FG/H (RC24)
Honda VFR750F RC24
Honda VFR750F RC24
New model based on a complete redesign of the VF750F, full fairing, alloy twin-spar frame, gear-driven camshafts, and 16 inch front and 18 inch rear wheels.[sentence fragment] The VFR750FG also had a cam sensor which was omitted from all later versions. US and Canada models had round gauges while all other models had square gauges.
The "Tarrif Beater"[opinion] 700cc VFR700F was almost identical to the 750cc version with minor changes to graphics (no 750 on the lower fairing), shorter stroke, different cams and ignition timing. The VFR700F2 was mechanically the same as the standard F but had an upgraded rear shock and fork internals alongside square gauges.
1986–1987 — VFR750RK (RC24)
Not to be confused with the VFR750R (RC30) the VFR750RK was the HRC race kitted version of the VFR750F. Designed for TT F1 and Endurance racing as well as AMA Superbike. The kit bumped the claimed power output from 105PS@10500 rpm to 125PS@12000 rpm[better source needed] due to engine changes including new titanium rods (steel for AMA), pistons (raising compression to 11:1) and cams with larger (optional titanium for the inlet) valves. A new ECU bumped the ignition advance by 5°. Depending on year either the original carbs were modified or a new set were offered as an option.
As well as the engine parts the kit options included a new radiator and optional secondary radiator, modified bodywork, wider wheels, new suspension (forks, shock and linkage) and the option for bars (replacing the clip-ons).[sentence fragment]
Minor revision with fairing redesign from a two piece to three piece along with 2-position flip up screen, exhaust redesign, stronger fork legs (up to 41mm from 37mm) but retaining anti-dive on the left leg, a more reliable ignition system and 17 inch wheels front and rear.[sentence fragment] Larger engine valves for improved midrange along with larger carbs. Gear ratios remain the same but the gearbox shift mechanism was upgraded to the same as the VFR750R (RC30).[sentence fragment]
A clock and fuel gauge were added and the pillion footrest mounts were changed from being part of the rear subframe to bolt on cast aluminium assemblies. New larger frame castings reduced the amount of frame welding. New fairing side-panels allowed easier access to the engine, and the fairing cutaways for the rider's feet were much reduced in area. The change in wheel size allowed both a greater range of tyre options and a claimed improvement in handling. This model was not imported into the US.
1990–1993 — VFR750FL/M/N/P (RC36)
VFR 750 F RC36
Major redesign with new frame and bodywork, cartridge forks, single-sided swingarm and wider wheels to accept more modern tyres, gain of some weight.[sentence fragment]
The bodywork revision evoked Honda NR design cues;[opinion] mechanically very similar to its predecessor, but dozens of minor and weight-saving changes made the bike lighter and more responsive to ride. Last of the VFR750F models before replacement by the VFR800Fi in 1998.