Review on Motormeters® Digital Back Light Meter Tachometer by Ronald Reese

Works too well. Very accurate RPM readings that update fairly continuously. It's amazing that you can change the battery without resetting the information. The amazing thing is that you can set service intervals (like a 10 hour oil change on the WR250F). Very easy to install. You must remove the tank to access the WR's fork. Another handy tip is that modern dirt bikes with boot style spark plug systems actually require you to wrap them around the plastic head of the boot. NOT the cable that leads to it. The image is a little blurry, but that's the gist. Also, for some reason this type of ignition must be messing something up when it detects a spark as you need to set the gauge to 2-stroke settings to get an accurate reading. So don't worry if your bike is idling at 3500rpm when you first install it (it was a bit spooky), just change the setting to 2-stroke instead of 4-stroke. I don't know why, but hey, this thing works great! Absolutely great for the price. No trail rider should do without it.