Bimota DB4

 

 

 

Make Model

Bimota DB4

Year

1998
Production 264 units

Engine

Four stroke, 90°“L”twin cylinder, SOHC, desmodromic 2 valves per cylinder 

Capacity

904cc / 55.2 cub in.
Bore x Stroke 92 x 68 mm
Compression Ratio 9.2:1
Cooling System Air cooled

Induction

2x 38mm Mikuni  carbs

Ignition

Electronic inductive 
Starting Electric

Max Power

58.3 kW / 80 hp  @ 7000 rpm

Max Torque

81 Nm / 8.3 kgf-m / 59.7 lb/ft @ 7000 rpm

Transmission

6 Speed
Lubrication Wet sump
Final Drive Chain

Front Suspension

Telehydraulic fork with 43mm stanchions and preload adjustments

Rear Suspension

Fully adjustable monoshock absorber, swingarm

Front Brakes

2x 320mm discs

Rear Brakes

Single 230mm disc

Front Tyre

120/70 ZR17

Rear Tyre

180/55 ZR17
Rake 23°
Wheelbase 1370 mm / 53.9 in.
Seat height 800 mm / 31.5 in.

Dry Weight

165 kg / 363.8 lbs

Fuel Capacity

20 Litres / 5.3 US gal

Consumption Average

5.1l /100km / 46.1 mpg

Standing ¼ Mile  

12.1 sec

Top Speed

212 km/h / 131 mph

Bimota has looked to a lean and simple V-twin to help pull it out of the smelly stuff. Back in 1985, the sales success of the DB1, its first ever Ducati-powered model, rescued the firm from a financial crisis. Now Tognon and his team are hoping they can pull off the same trick with the 1154, which combines the engine from Ducati's latest 900SS with an oval-tube aluminium chassis similar to that of the loopy Mantra roadster.

As usual Bimota doesn't make any internal changes to the 9()4cc, air/oil-cooled V-twin. Ducat) uprated the old sohc two-valves-per-cylinder lump for last year's 900SS, giving it new cams for slightly better breathing at high revs, Bimota adds its own twin-pipe exhaust and, surprisingly, replaces the Duke's new fuel-injection system with the previous model's 38mm Mlkunl carbs, complete with Bimota-designed airbox.

The chassis layout is almost identical to that of the Mantra, based around a triangulated tubular aluminium frame that weighs just 5kg. The cantilever swing arm - also aluminium -operates a diagonally-mounted Öhlins shock. At the sharp end, 43mm Paioli forks are held at a steep 23° angle.

Let's throw in some more little figures. With a wheelbase of just 1370mm, a seat height of 800mm and a dry weight of only 165kg, Bimota's DB4 is shorter, lower and lighter than Yamaha's R6. Even short riders will be able to plant both feet firmly on the ground, and you barely have to reach forward to the low clip-ons.

Like the 900SS, the DB4 won't appeal much to riders who demand power and speed above all else. The Duke's claimed peak output is a mere 80bhp at 7500rpm, and although the Bim's free-breathing exhaust means it barks louder, it doesn't have any more bite. Like the 900SS, though, the DB4 combines punchy mid-range with the old air/oil-cooled V-twin's lumpy charm.

The use of carbs retains the DB series' traditional simplicity, and they're cheaper. But during my ride on the hilly, twisty roads inland from Rimini, the Bim suffered from an erratic idle and an occasional slight glitch just below 5000rpm, suggesting the Mikunis needed better setting-up.

That didn't prevent the DB4 from being brilliant fun. Its low-rev snatchiness cleared at about 3000rpm. There was good power from four grand and even more from about five, before the sohc motor began to run out of puff at eight thou, 1000rpm or so short of the limit. In the 60-110mph zone where you spend most time on the road it was seriously rapid, aided by its light weight and broad spread of torque.

Acceleration tailed off above about 120mph, but with its pilot hiding behind the low screen, it would probably reach 135mph. More power would occasionally be nice, but on these roads that was plenty. Throttle action was light, the six-speed gearbox sweet, and the mid-range grunt made clutchless wheelies a doddle.

The DB4 lives up to Bimota's tradition for light, rigid chassis. With such sharp geometry and so little weight the little twin can be chucked around with ease, flicking rapidly from side to side with minimal pressure on the bars. Yet, apart from a slight tendency to be shunted off line by bumps in the road, it was super-stable too.

Much of the credit for that goes to the suspension. The fairly firm, multi-adjustable Paioli forks gave good feedback and helped make

this one of the sweetest-steering bikes on the road. And the Öhlins shock was excellent, keeping the rear end under control even when the Bimota was accelerating hard out of bumpy corners.

The familiar braking blend of 320mm Brembo discs and four-pot calipers had plenty of bite, although needing a fair bit of lever pressure. Pirelli's super-sticky Dragon Corsa radials found grip, even in the most dubiously surfaced bends. My only cornering problem was that in turns my right size 11 sometimes tangled with the carbon-fibre exhaust shield, which is too close to the footrest.

Other carbon parts and the DB4's patriotic red-white-green bodywork were finished to the high standard expected of Bimota, but not always achieved in the past. New boss Tognon is conscious that, as a manufacturer of premium-priced bikes, Bimota's quality must be impeccable. By Rimini standards the hand-assembled DB4 is competitively priced, but it's still more expensive than plenty of the far faster mass-produced machines.

Overall it's hardly a leap forward from the DB2 of a few years ago.

Same cobby engine, same flickable handling, same minimalism and overtly 'Italian special' styling. A tried and trusted evolution of a theme, and ideal for rebuilding trust in a company that needs it.

But after all the niche assessment that a bike like this evokes never forget that the DB4 is a seriously sexy ride.

Source Bike Magazine of 1999