BMW refurbished its iconic Flat Twin Boxer with a new cylinder head and not an increase in displacement.
The new DOHC radial valve head delivers an extra 5 hp and 3 lb-ft of torque, as well as a 500 rpm higher redline.
It was expected that BMW
would debut an upgrade to its iconic Flat Twin Boxer for the 2010 R series. Now the details are revealed, as 2010 motorcycle info leaks prior to the upcoming EICMA Milan Bike Show. Here’s what the spec sheets and PR machine say about the new Boxer.
No, the Boxer is not gaining any CC. Bore and stroke is identical at 101 x 73mm with the 1170cc displacement unchanged.
New DOHC Cylinder Head:
The 2010 Boxer cylinder heads feature cylinder head upgrades first used on the HP2 Sport. The DOHC design sources two chain-driven camshafts, with each camshaft controlling both an intake and exhaust valve in the radial four-valve head. The valves themselves have changed, with diameter increased on both intake (1.42-1.54 inches) and exhaust (1.22-1.30 inches), with valve lift also increased. Compression ratio is unchanged at 12:1, however, a new combustion chamber shape necessitates the use of red-designed cast-aluminum pistons.
Larger Air Intakes:
New black throttle butterfly manifolds are larger, up 0.12 inches to 1.97, and work with redesigned intake manifolds and air filter element.
All the motor tweaks add up to more power and a higher-revving Twin. Peak horsepower claims jump 5 hp to 110 total, with torque up 3 lb-ft to 88. The peak outputs come at a higher rpm, a respective 7750 (up 250 rpm) and 6000 (up 500 rpm). The redline jumps an extra 500 rpm as well, to 8500. Overall, BMW claims the modifications “provide a significantly more homogeneous flow of power and torque throughout the entire speed range.”
The exhaust system looks identical to its predecessor, but BMW promises a sweeter tune with a new internal structure to the rear can, along with an electronically-controlled exhaust flap. BMW describes the new decibels as “a particularly throaty Boxer sound naturally in full compliance with legal standards.” Naturally.
The new Boxer motor headlines the upgrades to three 2010 R-series machines announced by BMW: the popular BMW R1200GS
and its Adventure sibling, as well as the R1200RT tourer.
2010 BMW R1200GS & Adventure
Don't expect the BMW R1200GS to lose its best-selling status in 2010 with a new, more powerful motor at the ready. The new Boxer is utilized by the Adventure version as well.
After the engine upgrade, the changes to the 2010 BMW R1200GS
models consist of new color options: Alpine White, Magma Red, Ostra Greymatt and Sapphire Black for the GS; and Smoke Grey and Brilliant Yellow for the Adventure. The standard GS now also offers an LED headlight as an accessory option.
2010 BMW R1200RT
Changes to the RT model are more significant, with a redesigned fairing and rider cockpit. The fairing shape looks a little sharper, more angular. The new bodywork is teamed with the new magnesium-colored cylinder covers for aesthetic changes.
Behind the controls a rider is greeted with a refreshed instrument cluster, as well as new switch gear. That’s right, the old paddle shifters that were killed on the K series last year, have left the R1200RT for 2010. On top of the more conventional turn signal switch, the RT will feature and intersting Multi-Controller switch for its optional audio system. The new unit is placed on the interior of the left handlebar grip and works similar to a computer mouse with a rollable, pressable wheel allowing on-the-fly music selection without removing a hand from the bars.