African Twin: What is a DCT Transmission?

After two days on the CRF1000L we are talking about the dual clutch transmission.

These last few days Dirt Rider has been ripping around Moab, Utah, on the brand spankin’ new 2016 Honda CRF1000L Africa Twin. With this being a from-the-ground-up new model, there is a massive amount of information to share so we are going to break it up into chunks. This first installment is about the most unique feature on the Africa Twin, the DCT (dual clutch transmission), which has an MSRP of $13,699 and the standard shifting model is $12,999.

Side view of Africa Twin
You can see the DCT servos and extended clutch cover down where the normal clutch would be.Photo By Kevin Wing

What is a DCT transmission? The simplest explanation of this system is that the bike shifts automatically, just like an automatic car. But there are a lot of differences too. The clutch itself is actually two separate clutches that are oil-pressure actuated by two independent servos. Each clutch changes three gears – one clutch for 1, 3, and 5 and the other for 2, 4, and 6. That way one clutch is disengaging while the other is engaging making for seamless, almost imperceptible shifting. There are also four different “modes” that the DCT can be set to, depending on how aggressive you want to ride. D mode is for cruising around town or to maximize fuel economy and the bike upshifts very low in the rpm.

For example, just leaving the parking lot the bike in D mode the bike went click, click, click, click into fourth gear before hitting 30 mph. Then there are three S modes, each more aggressive then the last. Basically, the higher the S mode, the longer the bike holds a gear letting you reach higher in the revs before it shifts. Also, the higher the S mode, the more likely the bike will down shift (sometimes twice) when you whack open the throttle. There is no clutch lever or shift pedal on the DCT model, but it does have a left grip finger trigger and thumb button that lets you shift when you want to, even in any of the DCT modes. The finger trigger shifts up while the thumb button shifts down. Lastly there is a “manual” mode that lets you do all the shifting with the left grip buttons.

DCT up close
A close up of the DCT (dual clutch transmission). The squarish structure in front of the clutch holds the servos that use oil pressure to engage or disengage the clutches. The two diagonal sections on the top of the clutch cover are the oil inlets.Courtesy Of Honda

How does the DCT know when and how to shift? There are a few sources of input that goes into the system. Primarily, the ECU monitors engine rpm and throttle opening to decide when to shift and which direction. It also has a sensor that monitors the tilt of the bike so it knows if you are going up or down a hill. When climbing or decending, it will hold a gear longer for better torque(uphill) and more engine braking (downhill). Lastly it has a "G" mode where the clutch engagement is at its most aggressive – with the G mode off, according to Honda, it the shifts are a touch smoother, but you loose a hair of acceleration.

DCT diagram
One clutch controls three gears while the other controls the other three. By having two clutches, one engages while the other simultaneously disengages making shifts faster and smoother.Courtesy Of Honda

With less than 24 hours to digest our riding experience, we still have mixed emotions about this system. There are a few things that are mind-blowingly awesome while other aspects were less than savory. First, the few cons to the DCT system; overall, the system is reactive, not proactive. When coming into a corner, on the street or dirt, most riders downshift either before, or as they brake. Yet since the DCT has no way of knowing what is coming up and only responds to rpm, throttle opening and bike pitch, you have to start braking first to get rpms to drop, then the system downshifts. Another quirk is that upshifts can catch you off guard in the dirt. When tackling a tricky uphill section of the trail, if you are slightly accelerating, the bike could think it is time to up shift. But, it might do so right before a ledge or even steeper section. This happened a few times, and while the bike can’t stall, it did cause us to have an unexpected lack of forward drive.

As for the pros, there are far more than the cons. First and foremost are the shift buttons. At any time you can click those and either upshift or downshift without going through the typical process of pulling in a clutch lever, hitting a pedal, then letting out the lever. When riding off-road in S3 (the most aggressive) the shift points were close to where most riders would shift, but sometimes it was necessary to up shift in the sand to get better traction, or down shift before a tight turn or rock ledge. Secondly, the shifting is incredibly smooth and fast – smoother and faster than any human could shift with a clutch and a shifter. Not only are shifts nearly instantaneous, they don’t upset the chassis at all! When you twist the grip wide open and click the next gear taller, there is virtually no hesitation, you feel and hear the next gear engage.

With DCT, you can let the system shift and/or use the paddle shifters on the left side of the bars.Photo By Kevin Wing

Thirdly, since the bike can’t stall, it is like having a Rekluse clutch on steroids. With a Rekluse, you still have to shift and make sure you are not in too tall of gear or you risk roasting your clutch. But, even in full-manual mode, the DCT is sort of idiot proof and will downshift before idling. For example, if you are off-roading in manual mode in fourth gear but make a mistake (hit an unseen rock or dip, etc.) and have to come to a panic stop, the bike will click through the gears until you are in first. With a Rekluse you would come to a stop in fourth gear but then you would have to click down to at least second to get going again while the Africa Twin would be in first and ready to go right away, which is especially helpful if you are in a precarious situation.

Africa Twin Jump
This is when you want to switch to manual mode. The bike doesn't know that you plan to get a little air so it might upshift on the lip of a kicker, dropping your rpm and forward momentumPhoto By Kevin Wing
left grip
Here is a look the the left grip. The lowest button on the this side of the bar is the thumb downshift button and the gray trigger on the front of the bar is the finger upshift button.Courtesy Of Honda

Lastly, the DCT is great to have when you are tired, loaded down with gear, have a passenger, or any other more complicated riding situation. We would all love to believe that we are infallible motorcycle riders and could handle any off-road obstacle at any level of fatigue, but that isn’t the truth. When going for a long, multi-day ride (like adventure bikes are designed for) truly exploring terrain that you haven’t seen and it turns muddier, steeper, looser, or just nastier than you had anticipated and you just need to get through it, the DCT makes your life so much easier. Also, when hopping on the highway between dirt section, the DCT gives one less thing to worry about in traffic.

In the next installment we will be looking at the 998cc, parallel-twin, single overhead cam engine. Stay tuned!

Wall ride
Overall, the DCT is helpful and completely awesome in 90 percent of riding situations. And for the other 10 percent you have manual mode and the shift buttons.Photo By Kevin Wing

MSRP: $12,999 standard and $13,699 DCT
Engine: 998cc liquid-cooled 4-stroke 8-valve parallel twin w/ 270o crank & Unicam head
Transmission: Constant-mesh 6-speed manual / 6-speed DCT w/ on- & off-road riding modes
Fork: Inverted Showa® 45mm fork w/ 8.0 in. travel; adjustable compression, rebound damping & hydraulic adjustable preload
Shock: Showa shock w/ 8.7 in. travel; adjustable compression, rebound damping & hydraulic adjustable spring preload Two 310mm wave floating
Front: 90/90-R21 tube type
Rear: 150/70-R18 tube type