Is it really a problem?
I keep reading about speedometer error, which I have on my '05 SV650S. It is aggravating trying to add mph to have the correct speedometer reading. When I first got the bike, I wondered why every one was passing me! Then my son told me I was running 47 mph in a 55-mph zone. What can I do to correct this problem?
Billy Berry
Crawfordville, FL
There are a number of companies that manufacture devices to correct speedometer error. Such devices are usually programmable boxes that plug in to the speedometer sensor's wiring harness and manipulate the signal so the speedometer reads higher or lower by a set amount. We've used the Yellow Box from Black Robotics (www.yellr.com) on several bikes with good success and currently have a SpeedoHealer (www.speedohealer.com) for our Kawasaki ZX-10R project bike.
The Numbers Game
Where can I get OEM numbers like rake, trail, wheelbase, swingarm length and angle, and swingarm pivot location on the frame (X and Y distance from the headstock)?
Chris McVay
Via e-mail
Rake, trail and wheelbase are widely published; you can check any of the manufacturers' specifications pages for those numbers. Sometimes swingarm length will be mentioned in a specific model's press kit or brochure if it's a big change from a previous model. The only mention I've ever seen of swingarm pivot location relative to the headstock is in the '04 Suzuki GSX-R600 and 750 press kits. The trouble with listing dimensions that locate the steering head and pivot is that the critical measurement is not from a physical reference point at the headstock but rather the perpendicular distance from the steering axis to the swingarm pivot. This distance, along with rake angle and ride height, determines the location of the swingarm pivot. It's not something easy to visualize (or measure), and that's probably the reason manufacturers don't publish any numbers.
There are several ways to measure a bike's critical dimensions, depending on how exact you need them to be. Computrack (www.gmdcomputrack.com) offers the most common service that gives a good degree of accuracy. At the other end of the scale, you can measure everything yourself with a tape measure and protractor; it depends on what you're looking to do with the numbers.
Lost In Translation
Why does the ZZR600 on your performance chart post much slower numbers than the '02 ZX-6R it is supposedly derived from?
Tony Meroth
Via e-mail
The ZZR600 we tested in 2006 ("Get Real!", Oct. '06) posted quarter-mile times about a half-second slower than the ZX-6R we tested in 2001; the ZZR is based on the '00-'02 version of the R model. Roll-ons were also a bit slower, and the ZZR made a few ponies less on the dyno. A close look at our ZZR revealed that some of its suspension bits were of a lower specification than the R model's, and some of the engine's internals may have likewise been changed, hurting performance. We've noticed similar discrepancies in reincarnated models from both Kawasaki and other manufacturers in the past.