After the successful drag strip trip it was time to see what our super 600 could do in a standing mile event. Unlike the bleak conditions at the strip, the morning of the Mojave Mile event was crisp, calm and dry–perfect for big speed.
Unlike the drag setup, the lowering strap was ditched in favor of a slightly higher stance and the aggressive gearing was also swapped for high-speed cogs.
Like our pocket ace from Nitrous Express, we also brought a wringer to the Mojave Mile, Krystal Ahmad, a 4-foot, 11-inch, 100-pound test rider who could easily tuck behind the Gixxer’s small fairing.
With a few gearing changes throughout the day and some tweaks to rider technique the GSX-R600 eventually reached a best of 158 MPH on motor alone. To say that figure was impressive would be an understatement, as nearly topping 160 MPH at 3000+ feet of elevation in just one mile is serious business.
With the swap of a higher (numerically lower) rear cog it was time for a few nitrous passes, but not before replacing the 20-jet with the big dog 40 since we were still 12 MPH shy of our goal. In land-speed racing that’s a long way off though.
The only nail in a 50-mile...
The only nail in a 50-mile radius found its way into the back tire.
While we don’t recommend plugging a tire for top speed testing, sometimes you do what you gotta do for the sake of the story
Unfortunately the bottle ran dry on the first pass due to an oversight by the entire crew on hand. The second pass was equally unsuccessful since we played it conservatively by only spraying the nitrous at the top of sixth gear for a 161 MPH run.
As the sun began its descent and the afternoon winds picked up it was now or never. We huddled up and decided the nitrous would be activated in fifth and sixth gears. In theory this should have been enough to gain serious speed without spraying the nitrous long enough to cook the motor…or so we thought.
The ill-fated pass started like every other run, lots of clutch slip to get the taller gearing rolling followed by WOT. First, second and third came quickly, fourth began to string out and as soon as fifth hit, the N2O made acceleration audibly stronger. All through fifth the little Gixxer ran with a sense of urgency. Next came sixth and all was well until the end. As the bike neared redline it broke-up (misfired) just before the shutdown flags. When the time slip printed it read 165.6 MPH, but the Gixxer had been hurt in the process.
Back in the pits the crippled bike was running on three cylinders and was showing symptoms of a dead hole. Cylinder four was the culprit and when the spark plug was removed the damage was immediately apparent. The entire tip was melted off—ouch. A compression check further drove home the point that with zero psi, something went wrong.
A look at the data logging files revealed an AFR change, but not an incredible one. Out came the other three plugs only to realize they were fine–not even a hint of trouble. This explains why the AFR didn’t drastically change, because the three good holes helped mask the bad one.
Sure the 165 MPH run was impressive, especially considering other bolt-on literbikes were less than 10 MPH faster. But had the Gixxer made a full pull, 170 MPH was easily within reach. Like any project, when you walk the razor’s edge there’s a chance of getting cut.
Picking up the pieces
Once back at the SSB ranch we researched the datalog and discovered that the throttle wasn’t 100 percent open. We can’t really fault the rider as she’d never been on a nitrous bike before and had to handle a lot of instruction in a very small amount of time—at 165 MPH. The problem with being just under 100 percent throttle is that the nitrous fuel map isn’t activated until full throttle, which means the engine ran lean and got too hot. Luckily the spark plug took most of the heat and the number four piston was only mildly scarred. It wasn’t a huge issue but enough to shut us down for the day and determine that nitrous is only for experienced riders who are well aware of the repercussions of not adhering to strict riding technique.
Other contributing factors point to a possible distribution problem since only one cylinder took the hit. The substantial 40 HP shot (40 HP) also increased the odds since the bigger the hit the bigger the risk to stock engine internals. We pushed the motor to the edge and left little room for rider error. When that entered the equation it ended the day early.
The biggest disappointment is the monumental “What if” factor. Had the throttle been fully opened to the stop and the nitrous pushed for the complete run would the bike have broken 170 MPH? We can only speculate, but a gambler wouldn’t hesitate to make the wager that a buck-seventy would’ve come easily.