- Breaker points VS CDI -

Well you are going against what has been proven to work best.

Trust me a set of points with a broken spring or a dud ignition coil are just as un-fixable at the side of the road as a CDi box.

With a set of pionts you can see them working and fiddle about with, set them up and so forth; so you are happy in your mind about them. Cdi there is nothing to see and nothing to mess about with. As most people don't fully understand the system there is a lot of doubt about it.

On a simple engine like the SR you probably won't notice the difference between the two systems (except you have to mess about with the points every so often too keep the engine running sweet). But changing from points to electronic ignition on my XS650 totally changed the way the engine ran for the better. It was a different bike, ran smoother and pulled so much better.

If you have problems with SR CDi boxes I can supply replacements at far less then what Yamaha charge also test Yamaha boxes.

If you had any sort of misfire with the Cdi magneto there was a problem with it in the first place.

The SR Cdi magneto is a self powering device, independant of the bike's 12 volt battery system. It has a seperate set of windings that charge the capacitor that provides the spark. The magneto kicks out 20volts at 1100 RPM. With that it has to produce a spark hot enough to run the engine.

Above 4,000 RPM the CDi magneto is pushing out over 200 volts and the spark is very impressive. Your battery and coil is still producing the same spark as it did at idle.

With a battery and coil you are using the battery to provide the power for the spark and as the battery voltage is not affected by engine speed you will get the same spark at idle (or below that speed) as you do at the redline.


CDi works in the opposite sense to points (and TCI) in that it sends a pulse of voltage to the coil, instead of interrupting the supply. If you use a magneto to charge the capacitor, the faster the engine turns, the higher the voltage available to charge the capacitor and hence the bigger the spark at the plug (my CDi boxes are rated at 630 Volts with the output end able to withstand 1000 volts making them very over engineered) So where as your CDi magneto makes more power and a bigger spark as RPM increases your points in effect makes a weaker spark as engine speed increases due to the fact that the voltage supplied stays the same AND the time to charge the coil reduces.

I'll try my best to sort out any CDi problems. I can easily ship in Europe within a few days and I can occassionally deliver in person to Amsterdam, as I'm there for work from time to time.