If there is one thing that is always talked about when it comes to any Honda, it is the sky-high rev limits they are typically known for. The Ruckus isn’t even the exception, but it does come with a rev limiter of 8,900 RPMs. Most would probably assume it would have been higher considering most of their road bikes scream to 12,000 RPMs or more. Well, unfortunately the guys at the Honda factory wanted to make sure your Ruckus survives many, many miles of service and put the rev limiter to a safe and low limit. However, that doesn’t mean the Ruckus isn’t capable of some screaming RPMs. In fact with a Ruckus CDI, many have seen that the Ruckus is capable of over 13,000 RPMs.
They are capable of doing this by removing or circumventing the OEM Ruckus CDI control. They get around this by installing one of the many aftermarket Ruckus parts known as a CDI box. But, what is a CDI box? CDI stands for Capacitive Discharge Ignition. The CDI Box has a capacitor like component that stores energy and the ignition coil amplifies that energy to create the spark needed for ignition. Most CDIs are capable of putting out 250 volts to the ignition coil and some ignition coils are capable of 100:1 to 240:1+ step up, as the ignition coil acts as a step-up transformer. So instead of 250 volts, it’s quite possible that the voltage at the spark plug is closer to 60,000 volts! However, the peak voltage of the stock Ruckus is only 80 volts to the ignition coil and its step up is only 200:1 (16,000 Volts to the spark plug). Also, instead of charging the coil all the time and waiting for it to also recharge after every spark, the CDI is charged instead and allows for quicker charge times and higher RPMs. Thus, 10,000 RPMs are not unheard of and it is possible to go higher on the Ruckus GET Engine as some CDI modules have no RPM limit.
Most CDI modules for the Honda Ruckus actually just bypass the OEM control in the ECU. The ECU still sends the signal for the CDI box to fire; it is just now not letting the ECU limit the ignition to just 8,900 RPMs. I can’t go into complete detail on how that works simply because there are many ways aftermarket CDI boxes connect. However, usually there is still a signal to the coil by the ECU that the CDI box interrupts and sends its own signal in place of it. After that is where the CDI boxes go separate ways. Many keep the stock ignition voltage, some increase it. Some keep the stock timing; many advance it or allow the end user to adjust it.
