With the Intermot motorcycle show under way, embargoes have been lifted and information on new models is finally accessible.
BMW has two new touring bikes, the K1600GT and K1600GTL. These aren’t lightweight commuters; these are 160-horsepower, inline six-cylinder luxury liners, loaded with high-tech electronics and comfort features.
The K1200GT has a slightly more aggressive riding position than the GTL, the latter of which is designed “with very relaxed, comfortable ergonomics for long trips with pillion passenger”. These bikes (the GTL especially) replace the discontinued aging K1200LT, and their current direct competitor is the Honda Gold Wing.
These machines are lightweights compared to the Gold Wing. The 319 kg (703 lb) GT undercuts the Wing by 93 kg, and the heavier, 348 kg (767 lb) GTL by 64 kg, all weights measured wet, though the BMWs are weighed without the saddlebags.
Six cylinders and one throttle body.
The 1,649 cc, long-stroke engine (67.5 x 72 mm bore and stroke) produces a very flat torque curve that peaks at 121 lb-ft, and makes more than 70 percent of its maximum from 1,500 rpm.
Part of the massive low-end torque output can be attributed to the single, 52 mm throttle body, which is controlled via ride-by-wire electronics. Both bikes will have optional three-mode traction control (Rain, Road, Dynamic), the system based on the current DTC used on the S1000RR
Remarkably, the GT and GTL claim small-bike fuel consumption at approximately 5.1L and 5.3L/100 km (55 and 53 mpg) respectively. Fuel capacity is 24 litres for the GT and 26.5 for the GTL, giving the machines close to 500 km of touring range.
In the chassis department, an aluminum bridge-type frame ties the Duolever front and Paralever rear suspension together. Wheel sizes are 17-inch with supersport-sized 170/70ZR17 front and 190/55ZR17 rear tires. The rear tire has been specially developed for touring.
The K1600s feature standard-equipment xenon low beams that are fitted with a movable reflector mirrors and are self-levelling by using data gathered through ride-height sensors.
A new and unique feature in motorcycling is the K1600’s optional adaptive headlight. This system uses the machine’s bank-angle sensors in addition to the ride-height sensors to aim the headlight while leaning through turns via a servo motor.
The instrument panel incorporates a 5.7-inch TFT colour screen to relay information to the rider from the on-board computer, optional ESA II suspension settings, as well as the display for the optional navigation system.
Of course, no luxury liner is complete without on-board entertainment, and the K1600GTL sound systems will be iPod and MP3 compatible, as well as including a USB port and an AUX jack for plugging in other types of electronic media.
Also, North American models will include Sirius XM satellite radio. Sound system functions are also displayed on the TFT screen. The sound system will be optional on the GT.
Standard features include an electrically adjustable windscreen, xenon headlight bulbs, heated grips and seat, cruise control, on-board computer and integrated ABS.
Both variations will be coming to Canada (in dealers in the Spring of 2011), with pricing released and a preview model shown at the December Toronto show.
BMW K1600 GT & Honda VFR1200 F V4
PISTON AREA & HP
Engine displacement alone is a poor indicator of engine horse power.
Horse power output is dependent on two basic factors.
1 Total piston area
2 Compression Pressure
The limiting factors of these are:
1 Piston speed – until recently the upper safe limit at maximum HP was 4000 feet per minute.
2 Bore to stroke ratio – until recently the practical limit was 1.5 to 1.
3 Compression ratio – the upper limit about 13 to 1.
4 Volumetric effiency
5 Valve actuation system
6 Detonation
When considering HP it may be more helpful to consider bore and stroke as separate entities rather then combining them together as displacement.
To date only the Honda Goldwing 1800 and the VMAX 1700 have the greatest total piston area of any production motorcycle at 40 square inches.
The Triumph Rocket III has a total piston area of 37.7 square inches. Same as the BMW K 1600.
The Honda VFR 1200 F V4 has 32 square inches of total piston area or 8 square inches per cylinder. If Honda ever simply added a fifth cylinder as a V5 they would have that magic 40 square inches and a 25% increase in HP to get a maximum of about 180 rear wheel HP at 10,200 RPM. With a bit of luck the total wet weight could be about 650 lbs. Engine displacement would be around 1545 cc. This is still heavy for a sport bike but within reason for the sport touring class.
Engine stroke acts like a torque multiplier. The longer the stroke, the greater the mechanical advantage. In other words the longer the stroke, the farther the lower piston rod center is from the center of the crankshaft.
A nice stroke length that would allow reasonably high engine speeds but favourable lower engine cruising speeds and power would be around 64 to 68mm.
The stroke on the BMW K 1600 is 67.5 mm.
The stroke on the VMAX 1700 was not changed from the old VMAX and remains at 66 mm.
BMW 1000RR
The engine that appears to be at the leading edge of modern 4 cylinder technology is the new BMW 1000RR.
RWHP = 180
Piston speed at maximum HP = 4246 feet per minute
Bore to stroke ratio = 1.6 to 1
Compression Ratio = 13 to 1
Total piston area = 31.16 square inches.
If one of the major factors in HP is total piston area then BMW may be at the practical HP limit of 1000 cc 4 cylinder engine . We may have reached the upper practical design limit with a bore to stroke ratio of 1.6 to 1 and a total piston area of 31 square inches and a compression ratio of 13 to 1 with a piston speed of 4246 feet per minute at maximum HP.
The only obvious way left to achieve greater HP with a 1000 cc engine is to increase total piston area. That means the addition of at least another cylinder. Keeping engine width to a minimum limits the choice to a V5 or V6. Of course, it may be that manufactures really don’t want to be responsible in building such a monster for the general public on public roads.
I would suggest they don’t. The focus, at least for the next few years will be on control. The trend has already begun with ABS, traction control and variable mapping.
Based on the BMW 1000RR model a 10% increase in RWHP would require another 3 to 4 square inches of total piston area. A V5 would fit the bill nicely. Honda knows how to build a successful V5. The present reality appears that Honda has already fixed their sights on the V4 model.
I personally think a V5 1000 would be a nicer bike to ride in the real world with better lower RPM performance, even if they didn’t exceed 180 RWHP. A V5 would certainly be different and well received. It would go a very long way in bringing back excitement in owning a Honda. Something Honda needs badly.
PISTON SPEED
For many years the maximum safe piston speed at maximum HP on non-racing engines was about 4000 feet per minute. Maximum HP piston speed on many modern non-racing motorcycle engines is between 3600 to 3900 feet per minute at maximum HP.
Exceptions;
The new Honda VFR1200 F V4 at 4020 feet per minute at a maximum HP at 10,200 RPM.
The Ducati 1098 Streetfighter at 4033 feet per minute at 9500 RPM.
BMW 1000RR at 4246 feet per minute at maximum HP.
Example:
The piston speed at maximum HP of the Yamaha VMAX 1700 is 3897 feet per second at 9000 RPM.
The piston speed of the BMW K 1600 at maximum HP at 7250 RPM is a very conservative 3211 feet per minute.
I suspect the BMW K 1600 is in a rather mild state of tune. The performance is strongly focused on excellent low RPM power characteristics. The accent here is on touring rather than sport.
The very low piston speed of the BMW K 1600 would strongly suggest there is a lot of room for significant increases in RPM and HP. At a piston speed of 3900 feet per minute the engine RPM would be 8500. RWHP of 170 at 8500 RPM would not be unreasonable. With a total wet weight of 700 lbs it would be almost the same as a VMAX 1700.
Interesting times
Regards,
JAG
Wow, I really don’t know what the fuss is about! Looks like my wife’s scooter! Is there going to come a day when the classics are gone and i have to ride one of these? I guess then its time to retire myself and the HD Electroglide. :cry
Finally something different than a boring goldwing I’m not in this bike category but I appreciate the configuration of 6 cyl in line.
Good work BMW.
More for those that ‘need to know’.
Cheers!
http://www.gizmag.com/bmw-k1600-six-cylinder-motorcycles/16578/?utm_source=Gizmag+Subscribers&utm_campaign=8d30216ab8-UA-2235360-4&utm_medium=email
That fairing makes it look like a really big scooter.
I really like the look of the front end and dash, but the bags and top box look like they are Givi bolt on’s, not smooth and intergrated like the 1200 or gold wing, or even matching like the Harley Electra Glide, or the Victory Vision. Yes I know they are different style bikes, but i mean fluid design from the front to the arse of the bike, especially for a bike ment to replace the 1200lt. Just my thoughts, that being said, if one magically appeared at my front door with a “I”m free, ride me” sign on it, I don’t think you would be able to kick the smile off my face
Personally I’m holding out for the surely upcoming, 8 cylinder incarnation…
I’ve already put a deposit on mine. Without a doubt this is a $30K bike.
“Xenon beams tilt with the bike!” … and with the road too! :roll
Let’s hope they keep the price competitive, $30k for an optioned GT might be a bit rich for this economy :p
That said.. WANT
This is a bike my wife and I will enjoy!
Litle typo here “K1200GT/L”