Breaking New Ground

Breaking new ground.  The revolutionary current generation Yamaha R6 is bristling with new Technology driven by Global emission restrictions but derived directly from Moto GP.

The 2006 Yamaha R6 has taken a revolutionary jump forward this year, coming to the market bristling with hardware never before seen on a Japanese 600.  Each year, sport bikes from all the manufacturers get better and better with power leaping up each generation and the running gear becoming more and more capable for the street or the track.  However, this new screamer from Yamaha was clearly intended for the racetrack first and the street second, which is a venture that seems to be paying off.  This isn’t a first though, in the late 80’s Suzuki produced limited edition GSXR-R’s that sported flat slide carbs and dry clutches stock!  Yamaha then produced the limited edition and very expensive OW01, which had Ohlins suspension, wide wheels, close ratio gear box, ram air and an Aluminum fuel tank.  Kawasaki then dominated Superbike racing in the mid 90’s with the very effective limited build ZX-7RR, and that philosophy returned in 2003 with their street orientated ZX6-R (636) and the sharper edged ZX6-RR, intended for the track.  The RR Kawasaki sported race legal 600cc displacement, a close ratio gearbox, a back torque limiting (slipper) clutch, adjustable swingarm pivot and mounts for a steering damper, none of which is desired for the street, but they sold out like hot cakes.  Even Honda, always known for making excellent street bikes and not getting caught up in the hype around making race focused bikes introduced their CBR 600RR in 03, but kept their softer CBR 600 F4i in the line up to give buyers two options.  In keeping with this bi polar middleweight theory, Yamaha chose to retain their 05 generation R-6 (called the R-6S) into 2006 and introduce this new race orientated R-6

Of the technical innovations on the new Yamaha, visually the exhaust is the most striking, exiting and ending near the riders right heel which is about 16” ahead of where conventional exhausts end behind the passengers right footpeg.  This position doesn’t require mounting to the subframe to give the bike a cleaner, meaner look.  Following Moto GP trends, this pipe placement keeps the weight low and the mass of the exhaust closer to the bikes centre of gravity, allowing it to change direction quicker and pitch for and aft less dramatically.  The pipe is mated to the engines shorter stroke and larger bore, which makes more peak power at higher rpm.  This engine parameter uses shorter secondary tube length in the exhaust system allowing the overall length of the pipe to be this short.  This exhaust direction was seen on last years GSXR 1000 and continued over to the GSXR 600 this year with Yamaha taking it a step further incorporating an Exhaust Power valve as well.  The EXUP as Yamaha dubs it the Exhaust Ultimate Power Valve has been a feature only found on their premium litre bikes until now.

The second technical first for a mainstream Japanese motorcycle is located on the front fork.  This fork is a new Kayaba unit that sports not only rebound and preload, but also both low and high-speed compression adjustability.  The low speed compression adjuster controls low fork (not engine or motorcycle) speed motions, like those generated when decelerating and braking.  The high-speed compression adjuster, spring preloads the shims on the compression piston, which saves disassembling the fork to change the shim stack when high fork speed tuning is required.  Being able to tune the high-speed compression allows you improve how the motorcycle responds over the bumps.  This past weekend at the Parts Canada Nova Scotia Superbike National, several Yamaha racers were able to make big improvements to how their R-6’s handled the high frequency bumps found off the end of the back straight by adjusting this circuit on the fork.  The change takes about 8-10 seconds, vs. 1-2 hours for the competition’s fork and can easily be tested and fine tuned during a 25-minute practice session.

Another first I noticed when I started testing with the bike back in February was the on board o2 sensor located in the stock exhaust system.  Some high-end European fuel injected bikes have recently started using o2 sensors to monitor the accuracy of the fuel injection after all the other sensors have done their best to determine the proper mixture.  Sensors such as vehicle speed, airbox temperature, coolant temperature, intake manifold pressure, ambient air pressure, rpm and throttle position all do their best to determine the proper air/fuel ratio to meet ever increasing emission regulations while still trying to give maximum power.  As soon as I saw this o2 sensor I was concerned that if we installed a Power Commander to change the air/fuel ratio, the bike would be wise to the change and move the mixture back to maximize emissions, not power.  This however has not been the case, with the stock bike having several lean/rich dips that were easily corrected with the PC.  This leaves me to believe that the o2 sensor is more than likely just watching the mixture to protect the stock catalytic converter from excessive fuelling which will dramatically shorten it’s effectiveness and life.

Perhaps the biggest technical achievement showcasing on the new R-6 is the fly by wire throttle body system, which Yamaha dubs the YCC-T or Yamaha Chip Controlled Throttle.  As a first for a mainstream production motorcycle this system detaches the operator from the throttle bodies, directly anyway.  The throttle on the right handlebar turns a high quality potentiometer, with a stiff spring to make it feel like a set of carbs (or throttle bodies).  This potentiometer, then tells the ECU (at 1000 times per second) what you want the bike to do.  The ECU then polls the other sensors to decide exactly what it should do with the throttle plate, and how quickly to do it for maximum performance.  This protects you from the dreaded chugs when you foolishly pin the throttle in 6th gear at 1500 rpm (for example).  Advantages of this system are extremely precise metering of the intake air volume, which results in improved engine response, better fuel economy, and reduced exhaust emissions.  The single plate throttle bodies (most other systems require two plates or a plate and a slide) allow a shorter intake path for higher engine speeds resulting in more power.  The ECU can control and optimize engine braking, as well as simplify the idle control circuit all in throttle bodies that are lighter than normal.

Hats off to Yamaha, with technology pushing these bikes like never before, it is definitely an exiting time to be a sport bike enthusiast.