- Wed Jan 12, 2022 11:32 pm
#99694
If it is genuinely speed limiter and not a rev limiter, usually all you need to do is fool the system into thinking that's not the speed it's doing. That will depend on how it works out what speed it's doing.
They had a maximum design speed limit in Japan for a while of 120mph (yeah, I know) and the system for limiting it was surprisingly primitive for such high tech bikes. My grey import VFR750 had one. There was a little plastic disc in the back of the speedo that turned with the speedo needle with a notch in it at the 120mph mark. The disc sat in the middle of an optical sensor so when the notch lined up, the sensor made a connection and the ignition dumped the spark for 2 of the 4 cylinders. Feels like hitting a brick wall (bearing in mind you still have three gears to go at 120mph on a VFR750 and are nearing peak power output so it's dropping 50+bhp in the blink of an eye).
The simple workaround for this was to undo the sensor, stick a bit of plastic in the gap and tape it up. The only very slightly more complex workaround was to remove the sensor and connect a voltage divider (2 resistors) in its place to mimic the presence of an untriggered sensor (removing the sensor altogether didn't work, it had to have a specific resistance attached).
Given there is nothing new under the sun and there is an existing and long established way of fitting speed limiters to bikes, it might be worth having a look in the back of the speedo for a notched disc or optical switch?