What is a CDI unit on the Superdream models?

[McCabe-Thiele (Ted)]

I'm doing some more due diligence reading up on the CB500N Super Dream models - there are lots of references to the CDI unit.

So what on earth is a CDI unit & where does it do in laymans terms please?

[Bryanj]

It takes the signal from two small coils on the stator and uses them to fire the ht coils for spark, i seem to remember that it is not a true CDI ( Capacitor Discharge Ignition) but a sort of electronic compromise.
I think Ash has disected one and can give more details, i do know that the workshop manual gave testing details BUT you had to have a very specific analogue meter, from memory a Sanwa sp 10 d

[McCabe-Thiele (Ted)]

Thanks Bryan, I've an acute case of Insomnia that has lasted a couple of days - not normal for me whatever normal is.

[Bryanj]

Thats ok mate, im at work till 6!
That meter i did have one bought in Yokohama in 75, not sure if i still have it!
There was amother specified meter which had a different set of readings for testing.
Never had a cdi box go bad at Meads only 1 400 generator.

[McCabe-Thiele (Ted)]

I've looked throught the parts list, I can see the coil, CDI unit, unless I've missed it where are the points or is this built into the alternator unit with its own crank poition sensor?

[Johnwebley]

I've looked throught the parts list, I can see the coil, CDI unit, unless I've missed it where are the points or is this built into the alternator unit with its own crank poition sensor?

The CDI is the electronic ignition



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[Laverda Dave]

Thanks Bryan, I've an acute case of Insomnia that has lasted a couple of days - not normal for me whatever normal is.

It's the thought of buying another project bike Ted😉. I've gone to bed numerous times thinking about a problem with a bike and my brain then wakes up and prevents me from sleeping!

[magpie114]

And I thought it was only me that did that!


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[Johnny4428]

I’m the same, brain refuses to work at 11pm at night but 2am in the morning let’s get to work!😳

[McCabe-Thiele (Ted)]

Okay so no points, no crank position sensors, no adjustments, just a box that either works or it doesn't. That sounds like fun trying to work out why it won't start!

[Rozabikes Tim]

Sensor is on the flywheel that sends signal to the CDI ignition thingy...

[Bryanj]

It could be called a crank sensor but it is an extra small coil(or two) on the generator stator with a small lump on the permag rotor.
Stator and rotor must be changed as a pair

[McCabe-Thiele (Ted)]

My mind now boggles at how the advance & retard works - the magic of electronics  continues to baffle me.

I'm still amazed by our Microwave Cooker - I've stared throught that gauze on the door many times - never so much as a hello never mind a tiny, tiny wave.

[AshimotoK0]

CDi System different on 250N and 400N models.

The two coils on the stator associated with the CDi are prone to failure but there are people out there who rewind them.

Rex's speed shop do the testing guide attached, attached.

CDi unit itself is a potted assembly,

[SteveD CB500K0]

Given that microwave ovens work at 2.45GHz, Ted, I’m really surprised that you’ve never noticed the waves. The wavelength is about 12cm / 5 inches, so there’s no reason you shouldn’t be able to see them.




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