Topic: Should one coil get hot whilst the battery is on a charger? (CB400F)

[obrut]

Another symptom in the long running saga of my CB400F that went from running fine to not starting.

I'm currently charging up the battery and noticed that my 1-4 coil is pretty warm/hot.  Is this normal?  If not, what could cause it?



I've done every check/trouble shoot I can think of relative to both fuel and spark to no avail.  This bike is starting to wear me down...

[MoMo]

Does not seem normal but I always disconnect the battery and remove when charging.  Larry

[05c50]

The only way the coil should get hot is if the ignition is on and the points are closed. There should be no power to the coil if the key is off.

...............Paul

[obrut]

Thanks guys - key was left on.  I'll see if it cools down with the key off.

[05c50]

Also check the points for that coil, you may have burned them some. You should be able to clean them up though.

........Paul

[obrut]

It runs!

Back to basics - pulled, cleaned and regapped the plugs, recharged the battery, checked all the earths.

Still don't really know what caused it to refuse to start - best guess is really fouled plugs.


Ps. Thanks for the tip Paul - the bike has a prestolite ignition so no points.

[hondaface75]

so, I noticed my 1-4 coil was warm today after I left the ignition on for a bit. You say it will only happen if the points are closed and could have burned the points. Is this a common thing, is there a way to correct this and prevent it from  happening again? I imagine as well this would drain the battery if left on for too long? 75 750k btw. And I used the search function, so dont burn me for bumping such an old topic

[Bodi]

Easy to "fix". Turn the key off when the engine is not running.
For testing other stuff with key on, switch the kill switch to "off" and the coils have no power.