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DC inductive ignition system
Nearly all performance orientated production motorcycle engines now use inductive rather than CDI type ignition systems, as the longer spark duration provided by the inductive system is required to ensure complete combustion with modern lean burn power unit designs.
Much older engines, often with relatively inefficient combustion chamber design, also tend to run a great deal better if inductive type systems are used. This is particularly so if alcohol fuels are in use, as these are much slower burning than petrol and power output can be usefully increased through longer spark duration.
CDI systems supply a much shorter duration spark of higher intensity than the inductive type, and this makes them ideal for use in applications such as garden machinery and chainsaws for instance, where easy starting is much more important than how well the particular engine might perform after it has been started.
However for serious competition use with 4T motors the basic AC self generating CDI
systems are less than ideal, as their advance characteristics, are sometimes not
able to provide the best possible performance. If there is any doubt about this,
then its a good idea to compare the information on the advance provided by the supplier
of the AC-
Up to now unless riders of older machinery wished to retain their points triggered OE inductive ignition systems, the only alternatives available have been CDI based systems, which as outlined earlier may well not be ideal for applications where the best possible performance is required.
DC inductive ignition system
Click to enlarge
* Finally please remember that all of the above information is provided on the strict proviso that any modifications or changes not carried out specifically by Classictrial, are not guaranteed or warranted in any way, and are entirely the responsibility of the individual carrying them out, and that Classictrial are not responsible in any circumstances for damage or injury, that may occur as a result of poor workmanship. *
Race Tech Developments (RTD) are currently carrying out initial testing of a completely new DC inductive ignition system, which is fully programmable to suit each particular application perfectly, and uses modern state of the art components, and will provide noticeably improved performance, as well as increased reliability.
The system can be powered through a machines OE generator (with rectified output), or as a stand alone completely self contained unit using a very compact, lightweight, lithium polymer battery pack. Run time from a fully charged battery pack, is more than enough to last for a whole trials or motocross event!
RTD are hoping to have a production system ready for long term testing very soon, but initial tests with a prototype unit have proved to be very encouraging, and seem to suggest that this system is likely to offer big advantages to competitors who have it fitted to their machines!
Finally for anyone interested in learning more about the differences between inductive and CDI ignition systems, these web pages explain things very well indeed.