Why wont my ignition light go out?

[Kul]

My ignition light stubbornly stays on even though I've replaced the dynamo and battery and other that its running well.  Any ideas would be appreciated. Thanks.

[Goody]

First thing I would do.  With a volt meter check voltage accross the battery terminals.  If under 12 then battery is week.  If reading is only 12 or 12 1/2 then the dynamo is not charging.  Note:  Most dynamo's do not charge at idle speed.  Rev engine about 1,000rpm higher than idle.  If volts do not come up to around 13 or 14 then the dynamo is not chargeing at all.  I would then look at the voltage regulater.  Now remember most electrical problem can be traced to a bad ground (earth).  

If the voltage is good and you see chargeing then I think it might be a bad connection at the light.

Don't just assume the dynamo is bad.  You can check the voltage form the dynamo to the input of the voltage regulator.  If on high idle you get more the 12 volts then most likely the dynamo is good.

One more thought.  Overhere most dynomos need to be excited when first installed as to pos or neg ground.