2003 Yamaha R6

Death of 750s

A survey of Spanish chicas at the track determined that you should actually get the black one with the red
flames which is not pictured here.

 

If I were to start one of those evening arguments about motorcycles which are held between enthusiasts at gatherings across the country I would put forth that the modern 600 sportbike era came of age in 1997 with the introduction of the GSX-R600. Someone else at the table would offer up the FZR 600 or an F series Honda. I would disqualify those bikes by saying that, although they were fine motorcycles (to some extent) they were a far cry from the best bikes that those companies could have made. In other words, the YZF 750 was a far more sophisticated motorcycle than the YZF 600. The F2 was a retarded cousin to the RC30.

In 1997 the GSX-R 600 was released and, technologically, it was just as advanced as the GSX-R 750, only less powerful and lighter. At that time the 600 was more advanced than the big bore GSX-R 1100. It embarrassed the other 600s and raised the expectation of middleweight performance to be congruent with the best sportbikes, only with smaller engines. No more steel frames, no more cheap brakes, no more skinny forks. The GSX-R announced to the world “come heavy or don’t come at all.”

Obviously some industrial espionage was being conducted because Yamaha showed up the following year with the R6. The R6 stunned the middleweight segment with its stratospheric (but largely cosmetic) redline, its lithe form and its nimble handling. It bested the first generation GSX-R 600 by a slight, but noticeable, margin in almost all aspects but it also burned oil, had a fragile transmission and the frame, although cheap to replace, was a one crash affair. Yamaha tightened up the design, won a lot of races and proceeded to sell 65,000 R6s.



Subframe mounting bolts are now steel instead of aluminum and the subframe 
mounting tabs have vanished making frame damage an all or nothing affair. 
The center distance between the sprocket and the swingarm pivot is reduced 
by 10mm while the swingarm has been lengthened 10mm. The steering head
is 10mm higher. Anecdotal reports are that the frame, swingarm and subframe
are much more resistant to crash damage than previous R6s. The shock is a
triple adjustable Soqi with extra thread for ride height spacers. The spring ratio
is increased 4% and the linkage plate is 40% lighter by employing aluminum
instead of steel.

Just when Suzuki 600 racers were about to throw in the towel, the 2001 GSX-R was released with fuel injected R6 beating horsepower, lighter weight and a matching delicate frame. The GSX-R had edged back into the technological and performance lead again but racers found the new GSX-R has its own frailties with which to contend. In keeping with the younger brother status of the middleweight class, both of these 600s trailed the newer versions of their larger counterparts to market by a year.



The gorgeous black Deltabox III frame is entirely made of two 
castings, which are welded together at one location on either side
reducing welds from 16 per frame to 2. The subframe and the 
swingarm are cast as well. The frame is 50%  stiffer than the 
previous frame, which is claimed to approach R7 levels of 
torsional rigidity.

This year, and this R6, marks a new era in middleweight evolution. This year is the first time that the 600s are leading the way by sporting more technologically advanced features and construction that any other bike in their respective stables. This is a development that should not pass by unnoticed.

750s are dead, long live the 600s.


90% new

For Sale, 2002 R6, raced one season



My favorite headlights in the game right now. The left light is on for low beam. Both are
illuminated for the high beam. The lights use a single H7 bulb per side and are only
illuminated when the engine is running. The R6 inherits the shift light from the R1
(which is adjustable) and sports a large analog tachometer. The instruments also
have a clock (!) speedometer, odometer, two trip meters, low fuel meter. Fuel injection
error codes are displayed on the LCD.

For those of you with short attention spans, the new R6 is improved in every way. It would be difficult to put a fine point on exactly how much faster the new bike is but it is enough to win races. We rode the new R6 on a 58 degree day on the smooth and flowing Almeria Spain circuit with the European spec Michelin Pilot Sport tires. The US market R6s will come equipped with D208 street tires. Despite the cold temperatures the Michelins provided ample traction, but I had to rely more on experience (as in “well, I didn’t fall down on the last lap”) than the actual sense of traction at the moment.

The first aspect of the R6 that captured my attention was its ability to power lift with absolutely no machinations of throttle or clutch. Let the clutch out in first gear as slow as you like, roll the throttle open, when the tach hits 10,000, the front wheel lifts into the air, catch second before you find yourself buying a new LED taillight. That is a first for me with a stock 600.



Titanium innards reduce the weight of the exhaust system 2.2 pounds despite the
addition of the catalytic converter.

The older R6 had a sharper power band with a lackluster mid-range heightening the sense of acceleration on the top end. The ’03 has filled out the mid-range with more lift on the intake cam and the FI, which makes the top end seem tamer but this is an illusion. The improved mid-range coupled with the 15,500+ gives a vast powerband in which to play. Riding short chutes between two turns allows you to exit a turn at 9,000rpm and let the engine scream past its power peak at 13,000 another 2,000 rpm, arriving at the brake markers for the next turn with no need to upshift or downshift. Presumably some revisions in cam timing (or cams from the race kit) will allow the engine to make power higher into that rev range.



Similar to the FI that appeared on the R1 last year, the diaphragm
fuel throttle bodies impart an analog feel to digital fuel injection. 
The diaphragms keep intake air velocity high at times when the
engine has low RPM but open throttle settings. The injectors
themselves are smaller and more responsive than those used
last year. Error codes are displayed on the bike’s instrument
panel eliminating the need for extra diagnostic steps.

Last year we were introduced to Yamaha’s version of air metered fuel injection with the CV throttle bodied fuel injected R1. This year they have installed a similar system on the R6. The system works very well at imparting a carburetor type feel to a fuel injected bike.



New airbox is 7.6l (up from 7.3) with varied length velocity stacks (to spread out
powerband). Previous air box restrictions have been removed and a high response
air temperature sensor has been added to aid the 38mm diaphragm throttle bodied
fuel injection.

The power flows through a linear clutch with one of the best transmissions Yamaha has built. The shifts were low effort but secure and positive.



The clutch has been beefed up by replacing the first two friction plates from cast to
punched out plate for improved durability. The cam sprocket holes can be ovaled out
by enterprising home tuners to adjust cam timing. The cam chain tensioner is beefed up.
Note new engine mounting points.

The R6 has always been physically the smallest 600; narrow across the bars, narrow in the tank, short reach from saddle to handlebars. It is almost reminiscent of a Ducati. The revisions to the bodywork and ergonomics of the bike continue and extend this tradition. The bike feel small with a dense centralization of what mass it carries.



Welcome to 1993. The Yamaha finally gets a curved radiator. Curving the radiator
increases airflow and cooling by 30%. The fan has been moved to the upper left
(rider’s left) so the fan is pulling air through the hottest part of the radiator.
The fan is now shrouded for increased efficiency.

The small form, light weight and aggressive geometry coupled with a 60 series front tire conspire to make a bike that is nimble almost to a fault. The R6 flicks with low effort ease and makes mid-corner corrections even easier. The low effort “think where you want to go” steering gives an initial impression of the inability to hold a line, until I realized it was my own indecision upon which the bike was acting. Once I had decided where I wanted to go, the bike was more than willing to follow.



With a firm eye towards addressing the past deficits in the R6 transmission the ’03 has
got a heavier shift cam (more inertia keeps the drum moving positively into the next gear)
a bigger shift roller and redesigned gears with more positive engagement and strength.

The R6 does not come equipped with a steering damper. There were a couple of times when I noticed its absence.

The choice of a 60 series front is a little unusual. The 60 denotes a tire that is roughly 15% shorter in radius than the more commonly employed 70 series. The smaller front tire will give reduced steering effort at the expense of mid-corner feel (usually enhanced by trail, of which this R6 has an additional 5mm from the ’02) and the ability of the tire side wall to absorb bumps. It is up to the tire’s sidewall flex to keep the bike tracking when cranked over in a less than smooth turn where the suspension is least able to absorb bumps. The 60 series felt great on the smooth pavement at Almeria but most American racers (and street riders) will swap the front to a 70 series. To maintain geometry you will need to lower the forks, or, to be more aggressive, raise the back of the bike.



A stronger axle connects the thin walled forks (from 2mm walls to 1.5mm) while the
trail is increased 5mm from 81 to 86. The travel of the fork has been reduced from
130mm to the industry standard 120mm while the fork springs have been stiffened
up a bit from 7.5N/mm to 8.3N/mm. The front rotors are still 5mm X 298mm but
these are lighter since they have reduced the mounting points (from 6 to 5) and
the rotor pins (from 10 to 7). The new pads are better but still ain’t all that. The front
wheel is a five spoke design and is 4% lighter than the prior wheel. Brake calipers are
the familiar single piece affairs.

The forks have been tightened up with new springs (.83, still a little light for most US track riders) and shorter travel. Despite the forks being a little lighter than race spec (roughly 10%) the front end worked very well in stock trim although the adjusters are pretty maxed to get appropriate track damping, and that with street tires. The race kit comes with fork dampers with 20% more damping giving you an indication of where the revolver of your choice is headed. Even so, the stock set up works surprisingly well.



The rotor is 9% lighter and the stator is 22% lighter and the alternator has been
reconfigured to put out more watts at lower RPM and fewer watts at higher RPM.
The pistons have been redesigned including a10% thicker intake side skirt and
top ring thickness increased by 10%. Weight is maintained by changing to tapered
wrist pins. The connecting rods now employ high-tension connecting rods bolts
designed for angle torqueing. The rods are attached to a lighter (150g) and
rebalanced crank, which is purported to reduce bearing stress by 20%. Yamaha
has ditched the aluminum liners and is now ceramic coating the cylinder walls. 
Eliminating the liners has improved cylinder accuracy and cooling and reduced
oil consumption.

The gorgeous satin aluminum shock runs out of rebound adjustment before the rear end of the bike runs out of oscillation. The shock does not appear to be easy to re-charge with nitrogen so revalving will probably be an expensive affair and simply buying a aftermarket shock will be on every racer’s list. The stock shock on a smooth track with sticky, but street, tires will probably be adequate for all but the most committed track day riders.



The valve springs are the same operating pressure but now have 10% more preload.
The intake cam has more lift for more mid-range (typically lift is for low end, duration
is for top end). The head gasket has some additional passages to increase coolant flow
between the cylinders and the valve head. The groove in the exhaust pipe just past the
exhaust gasket creates a pressure well to broaden the powerband. The ignition coils now
fire only once per engine cycle and have a higher output per spark. The cam caps changed
to a six piece design for lighter weight. The valve cover is now magnesium.

The stylish windshield (coupled with what I think is one of the prettiest upper fairings on the market right now) is useless on the street but is surprisingly effective in a full tuck on the track. The braking system is top quality using the legacy single piece calipers. Although the new stock pads are better than those used in the past but they still don’t hit very hard compared to the pads available in the aftermarket.

On the street the R6 lacked in nothing but a larger fuel tank.



The R6 shares the fuel pump with the R1. It eats up a fair amount of the fuel capacity 
in the tank leaving you with 17L. It has a dry break fitting to prevent gas spills. The tank
is very narrow in the knees making it easier to tuck in behind the bodywork.

The big question is, of course, which 600 to buy for the upcoming race season. The GSX-R has remained the same and, in all truth, will be competitive next season but the ’03 R6 will not be giving anything away to it and might actually have established a small advantage with the chassis and revised motor.



Insulated secondary pipe and muffler shroud should slow down the burning boot 
syndrome. The catalytic converter is integral with the muffler. The air induction 
system is now integrated into the cylinder head eliminating the tangle of tubes 
and pipes from the front of the motor.

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