Sachs Roadster 650

 

 

 

Make Model

Sachs Roadster 650

Year

2005 -

Engine

Four stroke, single cylinder

Capacity

644 cc / 39.3 cu-in
Bore x Stroke 100 x 82 mm
Cooling System Oil/air cooled
Compression Ratio 9.5:1

Induction

Ignition  

Digital
Starting Electric

Max Power

50 hp / 36.4 kW @ 6000 rpm

Max Torque

56 Nm / 41.3 lb-ft @ 6200 rpm

Transmission 

5 Speed 
Final Drive Chain

Front Suspension

Hydraulic fork
Front Wheel Travel 120 mm / 4.7 in

Rear Suspension

Twin telescopic shock
Rear Wheel Travel 120 mm / 4.7 in

Front Brakes

Single 320mm disc 

Rear Brakes

Single 220mm disc 

Front Tyre

120/70 ZR17

Rear Tyre

160/60 ZR17
Seat Heright 760 mm / 30.0 in

Dry Weight

154 Kg / 339.5 lbs

Fuel Capacity

17.3 Litres / 4.5 US gal

YOU have to be pretty old to remember when Sachs last made complete motorcycles. So it seems like only yesterday to me when the W2000 rotary was launched in 1975. Confusingly, that particular model carried DKW or Hercules badges, two other famous German names absorbed by the company in its distinguished history.

In recent years two-wheeler links have been confined to suspension components, but now Sachs is back with a range of retros. First to appear was a 125cc V-twin, with 800cc and one litre variations to follow. In the meantime, the 650 Roadster is here, the odd bike out due to its single-cylinder engine.

Classic die-hards claim that a "one-lunger" offers the quintessential motorcycling experience, particularly if it happens to be British. Funnily enough, Triumph, the old British marque that survived the longest, abandoned large capacity road singles before Norton, BSA, Velocette, Matchless et al. Which might have told us something, but nevertheless didn't stop the Japanese from resurrecting the idea virtually the minute our home industry was bulldozed under Birmingham.
That's relevant here because developing engines from scratch demands huge investment, so Sachs shops in Japan for power units. Suzuki provides the Roadster's 644cc air/oil cooled motor, a slightly modified version of that used in the current XF650 Freewind. The chassis was designed by Egli, a company long associated with re-framed BMWs and, before that, Vincents. Although Sachs suspension is used at the rear, the forks of this eclectic package come from Italy, courtesy of Paioli.
Seeing the bike for the first time, it certainly looks distinct - distinctly odd, some might say. Twin-shock rear suspensions are so uncommon now that the pair of chrome springs sprouting under the seat immediately make the Roadster seem quaint. The second thing that strikes you is its length. In pursuit of racetrack handling, current sports bikes are about 4in shorter in the wheelbase and generally more petite.

After processing the available data, the word "Slow" pings into your brain's out-tray: slow handling, slow performance. You therefore tend to be fully loaded with preconceptions by the time you stretch over the long petrol tank and press the starter button.

But wait. This bumper bag of bigotry completely overlooks one important factor. Contrary to a myth created by bike magazines, not all motorcyclists spend their entire lives doing wheelies and pivoting round corners on smouldering knees. Some commute. Some enjoy pottering through the countryside on a sunny day wearing a smile and an open-face helmet. Some even go touring at less than 120mph. For them, a big soft single is ideal. I know this is true because I've owned one myself for 18 years.

While 50 horsepower isn't much by bike standards, it's enough to out-accelerate most cars up to 80mph, when the upright riding position starts to become a drag. As this speed also coincides with the point at which a thrum of vibration intrudes, it's really as fast as you'll want to go for long anyway, even in a Gatso-free world.

The engine is happiest in the 4,000-6,500rpm bracket. Although the huge 100mm piston can be persuaded to move at up to about 8,000rpm, the power curve is on a downward slope by then. At the other end of the scale, the price you pay for squeezing more horses out of a single becomes apparent. Trad Brits of the glory days pulled smoothly from low revs, a quality commonly referred to as "plonk". To do this they needed heavy flywheels and a mild state of tune. Modern high-tech singles aspire to be multis, with the side-effect that if you attempt to accelerate at less than 4,000rpm in the higher gears it feels as if the engine is jumping out of the frame. Sorry, they're all like that, sir.

Egli's chassis acquits itself well. While the wheelbase is long, the steering geometry is quite sharp, so the handling strikes a nice balance between stability and twitchiness. Sneers directed at the outmoded rear suspension seem uncalled for (I have a suspicion that twin-shock swinging arms will one day be re-invented as a fashionable solution to some of the problems created by monoshocks). It's actually easier to find fault with the lightly sprung and damped forks, which dive and pitch more than is desirable. Comfortable ride, though. The Grimeca brakes are fine, but those expecting two-finger "stoppies" will find the single front a bit heavy.

So what sort of motorcyclist will buy a Roadster 650? Well, a mature one. Be honest, do you really need a machine capable of lapping the Isle of Man TT course at 120mph? There are plenty of dual-purpose big singles on the market, but nothing else exactly comparable. Ironically, the bike that comes closest is the BSA Gold SF, built by the vestiges of the firm that was once the biggest plonker producer in the world.

Source telegraph.co.uk