400ex Weak spark and now NO Spark Please Read

[y2k400ex]

Just rebuilt my 400ex it has ran great and then it became hard to start. It had a really weak spark and now it has lost all spark. I have checked the voltage of the stator (getting 50 v output) and Ignition pick up (getting 0.5 v output) I don't have a peak attachment for my multimeter to check the peak voltage. Also checed everything per the service manual.

I swapped out the Coil, Voltage regulator, and the CDI box with parts off a running 400ex. Checked my tether kill switch too.
Checked the Ohm reading on the stator to ground and it is .90, cleaned all grounds and connections. Checked the Ignition switch. Brand new battery also.

has any one ever had a problem like this???

Any suggestions Please reply

I have done many searches on this topic with no luck

[Old Head]

Well sounds like your getting what you need coming out but its not getting to where it needs to go. Maybe you have a cracked wire somewhere. Try disconecting the power and ohm the wires to make sure they are all still one piece.

[redrider311]

the only sugggestion i have is to check the thin wires going by your coil.. make sure that one is grounded and that they arent cut etc. etc. i have had one come off during a race.. other than that im stumped man.. good luck :(

[y2k400ex]

well i just bought a Stator.... and have it overnighted to me. its the only thign i havnt changed yet i'll see if i works

[s23599e]

last week i have same probl...

check with ohmeter the stator.... black/red with ground

80 to 90 ohm...

me, i have 400 ohm, i change my stator now is perfect

[y2k400ex]

Changed out the stator still the same, no spark

stripped the wiring harness checking for loose wires or shor circuits found nothing

check the timing adn its still in time.

changed the cdi from my stock to my DynaFS and now i have a weak faint blue spark. not enough to start though.

I'm going to try another coil tonight... agian since i at least have spark now.....

[bradrenea]

I hate to ask the obvious, but have you tried a new plug? I have saw them that looked perfect but would not spark because of a short in the plug itself.

[y2k400ex]

I have a new NKG in it now its was just relpaced before my last ride. i'm gettigfn another tonight


also any one know of any after market high out put coils for the 400ex. I know MSD makes oone but it has to be useed with their system.

I have seen these on Ebay :
http://cgi.ebay.com/ebaymotors/Honda-400EX-400-EX-Racing-Coil-Piston-Cam-Exhaust-CDI_W0QQcmdZViewItemQQcategoryZ43976QQitemZ4614584 155QQrdZ1QQsspagenameZWDVW

but I have never heard of them.....?

[y2k400ex]

It was the COIL....... running now