Honda VFR750F

src: laudeman.com

The Honda VFR750F is a 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.

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.

Video Honda VFR750F

Race history

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

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.

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.

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.

Maps Honda VFR750F

Engine

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 or even install small cooling fans to prevent reg/rec units from overheating.

src: www.motorcyclespecs.co.za

Chassis

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.

src: i.ytimg.com

Suspension

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.

src: pages.cs.wisc.edu

Models

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)

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 mm × 48.6 mm (2.76 in × 1.91 in)
Compression ratio 10.5:1
Rake/Trail 27.5 degrees/4.3 mm (0.17 in)
Carburettors 4 x 34 mm Keihin CV type
11,500 rpm Red Line
Front tyre 110/90 V16
Rear tyre 130/80 V18
Wheelbase 1,480 mm (58 in)
Seat height 795 mm (31.3 in)
Fuel Tank 20 L (4.4 imp gal; 5.3 US gal)
Dry Weight 199 kg (439 lb)
Wet Weight 230 kg (510 lb)

Performance

From Cycle June 1986:

Curb Weight /W full tank Fuel: 505.5 lb (229.3 kg)
Power: 82.5 hp (61.5 kW) (rear wheel) @ 10,500rpm
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: 29.8 mph (48.0 km/h)
60 mph indicated: 57.15 mph (91.97 km/h)
Braking Distance:
From 60 mph 118 ft
Engine RPM @ 60 mph 4420RPM
Measured top speed: 151 mph (243 km/h)

1988-1989 - VFR750FJ/K (RC24)

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. Larger engine valves for improved midrange. 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 1,480 mm (58 in)

1990-1993 - VFR750FL/M/N/P (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.

Bore & Stroke 70.0 mm × 48.6 mm (2.76 in × 1.91 in)
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 1,479 mm (58.2 in)
Length 2,180 mm (86 in)
Width 700 mm (28 in)
Height 1,185 mm (46.7 in)
Rake/trail 26 deg/100 mm (3.9 in)
Fuel capacity 19 L (4.2 imp gal; 5.0 US gal)
Dry Weight 216 kg (476 lb)
Wet Weight 244 kg (538 lb)

1994-1997 - VFR750FR/S/T/V (RC36)

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.

Power 100 hp (75 kW) (claimed)
torque 53.9 lb?ft (73.1 N?m) (claimed)
Measured top speed: 152 mph (245 km/h)
Standing 1/4 mile: 11.6sec
Bore & Stroke 70 mm × 48 mm (2.8 in × 1.9 in)
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 1,470 mm (58 in)
Width 720 mm (28.3 in)
Length 2125 mm (83.7 in)
Height 1185 mm (46.7 in)
Rake/trail 26deg/100 mm (3.9 in)
Fuel capacity 21 L (4.6 imp gal; 5.5 US gal)
Dry Weight 209 kg (461 lb)
Wet Weight 236 kg (520 lb)

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