Honda VFR750F

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Honda VFR750F
Honda VFR750P.jpg
VFR750P police variant
Manufacturer Honda
Also called Intercepter
Production 1986–1997
Predecessor Honda VF750F
Successor VFR800
Engine 750 cc liquid-cooled DOHC V4 four-stroke, carbureted

The Honda VFR750F is motorcycle produced by Honda from 1986 to 1997. Originally intended as a sports bike to compete with the Suzuki GSX-R750 and Yamaha FZ750 it was reassigned to a sports tourer with its replacement in racing of the Honda VFR750R followed by the introduction of the more rounded 1990 VFR750FL. The fully faired motorcycle was introduced with a 104 horsepower (77 kW) liquid-cooled double overhead cam (DOHC) V4 four-stroke engine. All generations of VFR750F since 1990 had an ELF-designed pro-arm single-sided rear swingarm and since 1986 had durable, gear-driven cams.[1]

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 center of gravity, a wider front tire, a slightly shorter wheelbase (15mm) gear driven cams and six rather than five gears.

"Tariff beater" 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 penalized 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.

Race history[edit]

Although not designed as a race bike, in 1986 British racer Ron Haslam took a standard VFR750F to third place in a soaked Transatlantic Challenge race at Donington Park, UK [2]

A very 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 carburetors, weighing 165 kg (dry), even less than the factory RVF, was first seen ridden by Wayne Gardner at a Suzuka test against TT F1 machinery. Wayne trounced the opposition, smashing his four-stroke lap record by 1.5s. 6 Examples of the '6X' were built, 4 for the Domestic Championships and 2 for the American Championships.

The VFR '6X' was raced at the Isle of Man TT by Geoff Johnson, coming in 2nd to Joey Dunlop in both the F1 and Senior TT.[3]

In the United States 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 Flyin' Fred Merkel by only two points.

For 1987 Fred'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.[4][5]

The engine developed in the 6X became the basis for the factory racer, the VFR750R. An engine race kit was available for the 1986 VFR from HRC for $4,000 (USD), including a titanium exhaust.

Engine[edit]

The VFR750F models all used 748 cc 16-valve gear driven DOHC liquid-cooled 90° V4 engines with carburetor-based air/fuel induction; the bore/stroke remained the same for all 750 models at 70.0 x 48.6 mm (2.756 x 1.913 inches). 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° crank, instead of the 360 degree crank used in the VF and VFR750R.

In comparison to the VF750 almost every component had weight shaved off it, each con-rod lost 90g, rocker arms 6g, intake valve 0.5g, exhaust valves 1.5g, pistons 20g, piston rings 1.3g per set, valve springs 17g each.

The V4 engine has proven itself highly reliable, 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 miles). However, RC36 engines have been known to reach well over 50,000 miles without any need to adjust the valve clearances.

Second- and third-generation VFR750Fs have notoriously suffered from failed regulators/rectifiers, likely caused by heat damage. Although Honda eventually re-designed the replacement part, such that failures of the new, finned regulator/rectifier are rare, some VFR750F owners carry spare regulator/rectifiers[citation needed] or even install small cooling fans to prevent reg/rec units from overheating.

Chassis[edit]

The VFR750F was the first of the 750 class to have an aluminium twin spar frame, weighing just 14 kg and the nearest thing on the road to the VFR, the GSX-R also had an aluminium frame but it was of a conventional twin cradle design.

Suspension[edit]

First-generation VFR750Fs sported anti-dive (adjustable on some models) on the damping-rod front 37 mm Showa forks (uprated to 41mm 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.

Second-generation models had non-adjustable 41 mm 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, 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.

Models[edit]

The VFR750F can be divided 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)[edit]

New model based on a complete redesign of the VF750F, full fairing, alloy twin-spar frame, gear-driven camshafts, single-color paintwork, and 16 inch front and 18 inch rear wheels. The VFR750FG also had a cam sensor which was omitted from all later versions.

  • Fork Diameter 37mm
  • Bore & Stroke 70.0 x 48.6 mm
  • Compression ratio 10.5:1
  • Rake/Trail 27.5 degrees/4.3 inches
  • Carburettors 4 x 34 mm Keihin CV type
  • 11,500 rpm Red Line
  • Front tyre 110/90 V16
  • Rear tyre 130/80 V18
  • Wheelbase 1480 mm
  • Seat height 795 mm
  • Fuel Tank 20 litres

Performance[edit]

From Cycle June 1986:[6]

  • Curb Weight /W full tank Fuel: 505.5 lb
  • Standing 1/4 mile: 10.95sec @ 113.95 mph
  • Fuel Consumption: 45 mpg
  • Range (to Reserve) 189 miles
  • Acceleration:
  • 0-60 mph 2.4sec
  • In Gear Acceleration:
  • 45-70 mph
  • 4th 3.76sec
  • 5th 4.64sec
  • 6th 5.20sec
  • Speedometer Error
  • 30 mph indicated 29.80 mph
  • 60 mph indicated 57.15 mph
  • Braking Distance:
  • From 60 mph 118 ft
  • Engine RPM @ 60 mph 4420RPM
  • Measured top speed: 151 mph

1988–1989 - VFR750FJ/K (RC24)[edit]

Minor revision with fairing redesign 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. 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 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 USA.)

  • Fork Diameter 41mm
  • Front tyre 110/80 V17
  • Rear tyre 140/80 V17
  • Wheelbase 1480 mm

1990–1993 - VFR750FL/M/N/P (RC36)[edit]

Major redesign with new frame and bodywork, cartridge forks, single-sided swingarm and wider wheels to accept more modern tyres, gain of some weight.

  • Bore & Stroke 70 x 48.6 mm
  • Compression ratio 11:1
  • Carburettors 4 x 36 mm VP CV type
  • Front tyre 120/70; 3.5 x 17 wheel
  • Rear tyre 170/60; 5.5 x 17 wheel
  • Wheelbase 1470 mm
  • Length 2180 mm
  • Width 700 mm
  • Height 1185 mm
  • Rake/trail 26 deg/100 mm
  • Fuel capacity 19 litres
  • Weight ???kg

1994–1997 - VFR750FR/S/T/V (RC36)[edit]

Bodywork revision evoked Honda NR design cues; 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.

  • Bore & Stroke 70 x 48.6 mm
  • Compression ratio 11:1
  • Carburettors 4 x 34mm Keihin downdraft CV type
  • Front tyre 120/70 ZR17; 3.5 x 17 wheel
  • Rear tyre 170/60 ZR17; 5 x 17 wheel
  • Wheelbase 1470mm
  • Width 720 mm (28.3 in)
  • Length 2125 mm (83.7 in)
  • Height 1185 mm (46.7 in)
  • Rake/trail 26deg/100mm
  • Fuel capacity 21 litres

+weight 236kg Related models include the VFR400R (NC30), RVF400R (NC35), VF1000F/VF1000R (SC15/16/19/20), VFR750R (RC30), RVF750R (RC45), NR750 (RC40) and VFR800Fi (RC46).

References[edit]

  1. ^ Cycle June 1986 http://www.mediafire.com/file/zjzwfi0zjg1/Cycle_Comp.pdf
  2. ^ "1986 Transatlantic Challenge". Youtube. Retrieved 8 January 2016. 
  3. ^ "Race Results - The official Isle of Man TT website". Iomtt.com. Retrieved 2011-12-27. 
  4. ^ "VSB ~ 1986 Honda VFR750". Vintagesuperbike.com. Retrieved 2011-12-27. 
  5. ^ "Brian O'Shea: AMA Superbike Collector - Mr. Superbike Part II - Motorcyclist Magazine". Motorcyclistonline.com. Retrieved 2011-12-27. 
  6. ^ Cycle June 1986 http://www.mediafire.com/file/zjzwfi0zjg1/Cycle_Comp.pdf


External links[edit]