Topic: CDI Box question

[Mars]

I have a 1979 CB400T and I can't get it started, so I'm just wondering, what actually trips the CDI box? Is it the stator? I just want to get some spark so I was trying to figure out how to jumper it! Thanks!

[Mars]

And a note, I have all within correct resistance specification readings everywhere on the stator except for the green to white. There I get nothing, and when I test for short, my multimeter says I have a short. This is also the case with an extra engine I have. Is this an indication of a bad stator, and would that make the CDI box not function?

[Alan F.]

I have a CM400 and I know the ignition system you're talking about. Although I'll confess a lack of insight as to the theory of operation of the CDI box.  I might guess that it picks up a pulse from the one permanent magnet on the rotor when it's time to fire off a spark... maybe check the pickup coil for shorts to ground or an open circuit?
Alan

Do you know about the sites www.hondatwins.com and www.hondatwins.net ?
Lots of friendly know-how and talent over there too.

Chapter 8 in the Clymer manual tells all.  I forget just where I downloaded mine but probably a link from one of the above listed sites.

[bryanj]

I have the Genuine workshop manual with all the diagrams and test BUT the test have to be performed with one of two specified multi meters or the readings mean absolutely nothing.

Be advised that the "Kill" switch works different to all the SOHC in that when it is in the On position it DISCONNECTS the black/white wire from ground and it stops the engine by GROUNDING the wire as does the ignition switch so any spurious ground on the black/white wire will stop the ignition sparking

[Mars]

Thanks guys. I've just created an account on hondatwins.com and I'll post this question up there. It's getting frustrating. I have no spark at all and I've even had some real experienced help to no avail. Regarding the kill swich -

"Be advised that the "Kill" switch works different to all the SOHC in that when it is in the On position it DISCONNECTS the black/white wire from ground and it stops the engine by GROUNDING the wire as does the ignition switch so any spurious ground on the black/white wire will stop the ignition sparking"

You are saying that the SOHC bikes are not like CB400T and that the CB400T operated in the above mentioned manner, correct? And the black and white wires, are those coming from the CDI box?

[bryanj]

Correct. The SOHC kill switch interupts the power wire from the ignition switch to coil, the 400 twin grounds to kill