Honda RVF400

Honda RVF400

Manufacturer	Honda
Production	1994 - 1996
Predecessor	VFR400R (NC30)
Class	Sport bike
Related	Honda CBR400 Honda RVF750 Honda VFR400

The Honda RVF400R (NC35) is a motorcycle introduced by Honda Motor Company in 1994, powered by a V4 16 valve double overhead geardriven cam 400 cc engine and known for its supreme handling capabilities. There were two models, the R and the T, which differed only in their paint schemes. The RVF (as it was marketed by Honda in Japan) finished production in 1996, though unsold RVFs remained available to purchase from Japanese Honda dealers through to 2001. The RVF400R is the smaller sibling of RVF750R (RC45), as the VFR400R (NC30) was to the VFR750R (RC30).

The Honda RVF400R was the successor to the Honda VFR400R NC30, which ceased production in 1993. While at first glance there appear to be mainly styling changes between the VFR400R and the RVF400R, the actual number of changes are vast as the entire bike was redesigned with numerous identical looking components being totally different.

The obvious differences between the VFR400R and the RVF400R are that the front forks are of the upside-down type and the rear wheel takes a 17" tyre (the Honda VFR400R took a 18"), there are two air tubes that feed fresh air to the area just in front of the air box (this is not a ram air system, the airbox is unpressurised) and the headlights have changed from twin round headlights to twin 'fox-eye' lights (this is one feature not mirrored from the RVF750R (RC45) as the RC45 features twin large round headlights).

Unlike the VFR400R the RVF400R was only officially sold new in Japan. The RVF400R outputs slightly less peak power than the VFR400R (due to japanese regulations at the time) but has a stronger midrange. There is a Haynes Manual for the RVF400R.

Like other Hondas with gear-driven camshafts, the RVF's engine makes a loud 'whine' sound when operating. The exhaust note of the V4 engine is also different from that of a more conventional inline four. The 400 cc VFR and RVF models share a unique exhaust note with their larger siblings—the VFR750R RC30 and the RVF750R RC45—because of their 360-firing order ('big-bang') configuration.

The RVF400R has a reputation for excellent reliability and good build quality, though not quite as high as its predecessor, the VFR400R.

VFR400 to RVF400 changes

Honda RVF400RT

Engine

The carburettors were changed, the RVF's carbs featuring a semi-flatslide design and smaller diameter venturis (30 mm against the NC30's 32 mm) but claimed to be better flowing, the velocity stacks were also changed to allow a straighter flow into the engine cylinders.

The valve timing was changed with the exhaust valves opening earlier and closing later.

The engine position was changed with large cast sections of the frame now holding the engine lower down (these lower engine mounting points were unused on the VFR).

Frame and Suspension

While the front cartridge forks were changed from RWU to USD forks, they remained the same diameter (41 mm) and make (Showa).

The frame was totally redesigned, with engine mounting and steering geometry changes.

The swingarm while looking identical at first glance is narrower (192 mm against 202 mm) and runs on a smaller diameter spindle (17 mm against 22 mm) with the rear hub and brake mounting points changed.

Wheels Brakes and Tyres

The rear wheel was changed from 18" to 17".

The front brakes remained as 4 opposed piston calipers but the trailing pistons were increased in diameter from 25.4 mm to 27 mm (the leading pistons remained at 30 mm).

The Honda RC30 was fitted with a 'Pro Squat Rear Brake Linkage' that linked the rear caliper to the frame via a linkage through the swingarm (reducing rear wheel hop under braking), the NC30 had the swingarm machined to allow a torque arm shaft and featured the cast boss on the frame but the linkage was not fitted (probably for cost reasons) and the caliper was instead held in place with a simple torque reaction arm bolted into the swingarm (it is possible to modify the NC30 to fit the 'Pro Squat Rear Brake Linkage'). The RVF400 has lost all of this, the rear caliper is now held in place by a boss on the swingarm, it is not possible to easily modify the RVF400 to full 'Pro Squat Rear Brake Linkage' as the swingarm would require unmachining).

It is possible on the VFR400 to change the rear brake disk without removing the rear hub, it is impossible to do this on the RVF400 as the mounting plate is larger and the entire hub requires removal.

Exhaust

The exhaust has a number of changes, the main change is that the silencer and collector are now separate and the silencer is held to the frame by one mounting point rather than two.

The silencer is now aluminium and held by 3 bolts to the collector.

Dimensions and weights

The dry weight went up from 164 kg to 165 kg, overall width dropped from 705 mm (27.8 in.) to 685 mm (27.0 in.), overall height changed 1.075 m (42.3in.) to 1.065 m (41.9in.), wheelbase dropped 10 mm from 1.345 m (53.0 in.) to 1.335 m (52.6 in.)

Handling

The VFR400 is widely acknowledged to be a very good handling motorbike, the RVF400 is more of the same, the main difference being that while the VFR400 likes one line, on the RVF400 it is not a problem to change lines mid corner helped by the upside down forks

Overview of VFR to RVF differences

The differences between a VFR400(NC30) and a RVF400(NC35) are;

- obviously different body work, the RVF400 copies its bigger brother the RVF750 RC45

- The VFR has 32mm carbs vs 30mm carbs on RVF, but RVF has 'T' section vacuum piston as opposed to round section piston, this makes piston lighter and offers more throttle response

- The RVF has lower ratios in the first 3 gears of the gearbox to make urban riding easier on the clutch and rider

- The RVF has tuned metal velocity stacks to increase mid range power

- The RVF has increased camshaft timing, same lift but more duration and overlap

- Intake port/valve seat on the RVF is 19mm as opposed to 20mm on VFR

- The frame on the RVF is substantially different to the VFR, RVF clamps the motor in a different position and has more rigind mounting points, it is also a later generation frame design

- The steering head angle of the RVF is 25degrees as opposed to VFR's 25deg 20 minutes, which will give slightly faster steering

- The wheelbase of the RVF is 10mm shorter than VFR

- The trail of the RVF is 92mm as opposed to 96mm of VFR

- The handle bars of RVF are 10mm higher and 24mm close to rider which will give a more comfortable ride(moreupright)

- The fuel tank of RVF is 30mm wider at the rear

- The front fairing was wind tested with naca ducts feeding cool air to the exterior of the airbox (not true ram air), 6.5% improvement in aerodynamics over VFR

- Front forks of upside down design, with revised spring rate and dampening, stiffer dampening and spring over VFR

- Rear shock on RVF has integral compression canister, also has revised shock linkage and improved dampening and spring rate. Unlike the VFR shock, the RVF unit is not able to be taken apart for reconditioning.

- Front calipers are of more rigid design, with about 10% improvement in feel over VFR

- Rear rim is 17 inch an RVF, VFR runs 18 inch

- Rear single sided swing arm is different in its mounting to frame to reduce weight and increase

Racing

The RVF400 NC35 is still being raced in various classes including in the Manx Grand Prix on the IOM. The RVF has a hardcore following all over the club racing scene, having been a very competitive machine against the FZR400, GSX-R400, and comparable to the rest of the high performance inline 4 400s. This gem of the two wheeled variety is raced hard and fast amongst the last of its kind with AFM for the 2008 season.

HRC

HRC (Honda Racing Corporation) supply a number of parts to adapt the RVF400 for racing

Parts available include:

• A direct air intake airbox (using a scoop in between the radiator and frame, does not use the air tubes).
• Rear ride height adapter (A number of U shaped plates that fit in between the frame and shock).
• Oil Cooler (a CBR600 oil cooler can be fitted and the water pump drilled to fit the water takeoff)
• Jet kit
• ECU

Aftermarket Parts

There are a large number of aftermarket parts for the NC35, many of which are interchangeable with the VFR NC30. If an aftermarket full exhaust system is fitted, changing the oil filter may be problematic as some aftermarket downpipes are straight and do not have the bends in them to clear the filter.

Specifications

Dimensions
Wheelbase	1335 mm
Length	1985 mm
Width	685 mm
Height	1065 mm
Ground Clearance	125 mm
Engine
Configuration	399 cc liquid-cooled 90-degree V-four
Bore and Stroke	55.0 mm x 42.0 mm
Compression Ratio	11.3:1
Valve Train	DOHC; four valves per cylinder
Peak Power (crank)	53 hp @ 12,500 RPM (stock)
Redline Begins	14,500 rpm (15,500rpm with HRC ECU)
Carburetion	4 x CV 30 mm bore
Exhaust system	4 into 2 into 1
Drive Train
Transmission	Close-ratio six-speed
Final Drive	Chain
Primary Reduction	2.117:1
Final Reduction	2.533:1
1st	3.307:1
2nd	2.352:1
3rd	1.875:1
4th	1.591:1
5th	1.435:1
6th	1.318:1