Due to Suzuki not importing any 2010-model GSX-Rs stateside we used a brand new ’09, which they put Yoshimura in charge of modifying.
For 2010 Suzuki opted not to import its GSX-R line of sportbikes to the U.S., or any street bike for that matter, instead allowing dealers time to sell the overstock of 2009s they already had. But as the ‘10 bike remained totally unchanged in the overseas markets that did get it, for our purposes a brand-new ’09 served just fine.
American Suzuki opted to hand their GSX-R600 over to tuning experts Yoshimura, as a project like this was right up their alley. Yosh installed its R-77 full titanium exhaust with carbon end can, EM-Pro ECU and engine management program with matching ignition harness, as well as its Ride Height Shim Kit for the rear shock. AFAM 520-size sprockets with an RK gold chain were installed to update the final-drive gearing, rounding out the Stage 1 changes.
On the dyno the horsepower and torque numbers of the Stage 1 Suzuki correspond similar to those of the stock bike in how it stacks up against the other unmodified machines. Horsepower is second to the Kawasaki while the torque
output just edges the green bike for top spot, which is exactly how they are pre-modifications. The major difference is the gap between the Kawasaki and the Suzuki in terms of peak hp once modded. The stock Suzuki makes 105.15 hp compared to 105.87 hp for the Kawi, while in modified from the Kawasaki boasts 117.94 hp compared to 112.32 hp from the Suzuki – quite a gap. In terms of torque they stay very close, as the Stage 1 Kawasaki is slightly back of the updated Suzuki at 45.97 lb-ft compared 46.30 lb-ft, respectively. As for stock toque numbers, the GSX-R pumps out 43.91 lb-ft and the ZX-6R makes 42.75 lb-ft.
Another gain with the addition of a full-titanium and carbon exhaust as well as 520-sized gearing is less weight. The stock ’09 GSX-R tipped the scales at 422 lbs full of fuel, while once modified it dropped 18 lbs to roll across at a dainty 404 lbs ready to ride.
With the addition of Yoshimura’s R-77 exhaust (middle) and EM-Pro ECU (bottom) the Suzuki put out a solid 112.32 hp and 46.30 lb-ft of torque.
How did this all translate on the track? Somewhat the opposite of how it did on paper. Several of the testers rated the Suzuki’s engine to be one of the weaker of the bunch, though at the same time the bike produced competitive lap times. This is because the GSX-R has a case of deceptive quickness. Through very precise tuning the Yosh bike has virtually no hits or spikes anywhere in the rev range, making for a seamlessly-smooth powerband, one which can easily be interpreted as ‘slow’ or ‘lacking’ even though it’s quite the opposite when you look down at the stopwatch or glance at the dyno charts.
Sorensen saw past the smooth power delivery and realized just how capable the GSX-R engine can be. “The Suzuki engine is deceivingly fast,” Sorensen comments. “While it doesn’t have a strong hit anywhere in the rev range, if you are running alongside any of the other bikes the Suzuki keeps up just fine. The power is smooth and seamless all the way through the rpms.”
When it came to the gearing the boys at Yosh guessed the best they could for both Willow tracks. Without any stock 600 data to go off of, they opted for a 15/44 combination at the big track and 15/43 at streets. While a noticeable difference over stock, the combination they ended up with was best suited to run as a five-speed at big Willow and lacked some slow-speed drive at Streets.
“The Suzuki’s gearing could have been better matched for both tracks,” continues Sorensen. “It still worked alright, though we never got into sixth at the big track and the drive out of the final corner at Streets suffered. A few teeth up at both tracks may have made a difference, which is something I’m sure they will look into for Stage 2.”
While the engine saw a split among rider opinions, the chassis definitely did not. With a low-slung seat and compact bar position, the rider sits far more “inside” the Suzuki then the rest of the current 600s, giving it a secure and planted feeling. Combined with the Yosh shock spacer that adds much-needed weight to the front of the motorcycle and the very capable Showa fork, the GSX-R’s handling was a shining point at both the uber-fast Willow Springs and the tight-and-technical Streets of Willow.
If there were any issues with the Suzuki’s suspension at all it would be the stock shock, which had a tendency to overheat and give up the ghost rather quickly, so to speak, allowing for a good deal of rear-end movement. But the GSX-
The additional power and always rock-solid handling of the Suzuki made it very competitive in this group, though gearing held it back ever so slightly. Can it make up the gap in Stage 2?
R was by no means the only bike that suffered from this issue, as the Achilles heel for all the stock 600s is without question the OE shocks – some were just more vulnerable than others. The GSX-R ranked right in the middle.
“The Suzuki was probably second-quickest on turn-in behind the Yamaha and I think a lot of that comes from adding that spacer,” adds Sorensen. “It’s still very neutral while flicking left-to-right extremely easily without being twitchy like the Yamaha could be at times.”
Says Neuer: “The Suzuki is super easy to get turned in, making me very confident at all times – it really felt like it was on rails at both tracks.”
The deceptively-quick engine and solid chassis set-up translated into competitive lap times. At Willow Springs the GSX-R went third-quickest overall at 1:27.89, though only half-a-second off the class-leading Kawasaki which turned a 1:27.36. The same held true at Streets of Willow, where it finished P3 with a 1:19.61, this time less than four-tenths back of the first-place Honda which did a 1:19.27.
Comparing these times to the original shootout in stock trim from ’09, where the Suzuki did a 1:21.03 at Streets (we were unable to get times at Big Willow last year due to rain), it shows a gain of 1.42 seconds through only a few basic modifications. With the exception of the Honda, the Suzuki gained the biggest of the group on the stopwatch.