What the heck is a yellow box? It's that little gadget in the picture above. In brief, it's just a nice little gadget that will correct any error you may have in your stock speedometer reading.
The stock bike generally runs an error in the range of 10% -- meaning that most riders who see a speedo reading of "100 mph" are actually only going 90 mph true speed. If the speedo reads "186 mph" , then you are probably going somewere around 168 mph true speed. This error is built into the bike the day you get it. It's a sure thing that you are not going quite as fast as your speedometer says, but the exact amount of the error varies by model year and also a little bit from bike to bike even in the same year. Of course, most riders would just like to be able to correct this, and know exactly how fast they're going.
Also don't forget that the odometer reads from the speedo, so if your speedometer says you're always going 10% faster than you are, then the odometer also "thinks" you've travelled 10% further than you have. This can be pretty significant - if the odometer reads 10,000 miles, you're bike probably only has 9000 true miles on the bike.
If you've changed the sprockets on your bike, that only makes this error worse - much worse.
Most riders put on a front sprocket that is 1 tooth smaller than stock, or they change to a rear sprocket that is 2 teeth larger than stock. Either way, you're making the engine turn MORE times for each mile than it would in stock configuration. The result is that the speedo will read even FASTER (incorrectly), and the odometer will move even more quickly than on a stock bike.
Motivated yet? Well, the yellow box will correct this error. All you need to do is feed the input from your speed sensor into the "yellow box" -- it will multiply the indicated speed by a "correction factor" and output the result to your speedometer that is the corrected speed. YOU have to program the box to tell it what that correction factor is. To determine your corretion factor, find a road with mile markers on it, ride 5 miles actual distance, see how many miles your odometer indicates (5.475 miles), and divide to get a ratio (1.095). The numbers in parentheses are what I got with my Gixxer.
Click the image above to go to the manufacturer's web site, which has a full explanation of the device and installation. Of course you can order there as well for $100. See below for my own pictures and comments.
Go to TOPSee the full installation notes from the manufacturer web site in pdf format if you need more help. My own notes are below.
First locate the speed sensor. This is located on the left side of the bike, held onto the side with a small allen bolt.
Now lift remove the gas tank, look straight down. You'll be able to follow the path of the speed sensor cable from the left of the bike where you saw it before. Look for this black plastic connector and unhook it so you can remove the entire speed sensor cable. This way you can put it on your desk and do the wiring while sitting down comfortably.
Here's what the speed sensor cable looks like, when removed from the bike
Cut off the thick black covering over the speed sensor wires. Separate the wires.
Take some spare wires, colored R,W,G,B and make all soldering connections as shown in the diagram. These should be very long wires that you can run all the way from the trunk compartment to the location of your speed sensor.
Next, mount the yellow box in the trunk before re-installing your speed sensor cable. Then run your wires down, under the frame, around the plastics, etc, to reach the proper location under the tank. This is definitely easier if you take the tank off. Once all your wires have been run, THEN you can reattach the speed sensor
You can see my multicolored wires here. I used some long runs of extra colored wire to make the long distance from the speed sensor wire to the trunk. Although the yellow box is well-sealed,it is NOT waterproof, so be sure to put it in a protected location away from water
Here's my mounting location - can you see the yellow box? it's the tiny gadget just in front of the grip lock. I just used some hot glue to fix it there.
There's still plenty of room to carry the really important things.
The instructions from the yellow box web site explain this quite well. The problem for many of us is that we don't have
Well, here is what I would suggest. Some buddies at Gixxer.com took many measurements using a GPS device. The idea is to compare the stock GSXR speedo readout to the actual speed by GPS, figure out how big the error is, and program the yellow box to fix that error. By a summary of many measurments, our working estimate for the ratio of display speed to actual speed was 1.095, meaning that the stock speedo without any yellow box correction was reading 9.5% faster than the true speed as measured by GPS.
So if you cannot take your own measurements, I'd suggest using that ratio for now. It'll get you closer to reality than just using no correction at all. So how do you set this up on the switches on the yellow box? There are eight switches on the top of the unit. Each one must be set to a zero or a one. Just set them up as 0010 0110. Some time when you can get your own GPS unit, you can take your own reading and make any minor correction to this.
Go to TOPThis is a nice little gadget that everyone should have. Installation is quite simple. The only problem is the cost - about $100. But once you have it setup, it will last a lifetime. And it's good not having to guess about your actual speed.