Hope this forum is non-denomenational for a desperate member

My 1975 CB400F. Beautiful bike. Is currently dead as a doornail. It ran one minute and was 100% dead the next. No light, no spark, no nothing. Changed to known good battery. Dead. Changed all fuses. Dead. Jiggled all the grounds and etc still dead. It will spin over if I jump the solinoide.

Anyone have any ideas? Wiring schematic posted here.

Where do I check this with my meter?
Any help appreciated. Very frustrating.

 

 

Is this a stock bike with stock wiring?

key switch on
kill switch set to run

meter DC V
black probe on negative battery post(post is the metal part of the battery)
red probe on positive battery post
note voltage

move your red probe to the fuses.
measure both sides of each fuse
what are the readings?

turn the key off
 

The best place for the help you need is sohc4.net

 

I've been trying to gain a user name there to post but no dice. My profile never gets approved so I thought I'd try here. Thanks F64.

Before you turn your key off
move the red probe to the ignition switch connector and probe each of the 4 wires.. all should have battery voltage.

turn off bike

 

What are the odds, ha. Check you're ignition switch as mentioned, they fail but the switch can be replaced without changing the key tumbler. Also your clutch lock-out switch. Then..notorious crappy designed (Start-Headlight Out) switch in RH switchblock lower. These seem to always fail. It combines starter function and turning headlight off during the process. Lots of times they will come out in pieces. 

<<<The best place for the help you need is sohc4.net>>

Does anyone know an admin there who can get my membership okayed?

Same bike! Same color. You can hit that blue with the polisher and it will come alive.

God bless you F64.

Honestly, one of the prettiest bikes ever made. Good luck with the F. 

ThatGPzGuy wrote:

Honestly, one of the prettiest bikes ever made. Good luck with the F. 

I totally agree. The 400F has always been that one 70's CB model that really stood out to me. They are super cool. I've never had a chance to ride one...

But...don't forget about the "Original"! Missing a gear, pistons the size of dollar pieces and not as sporty, still cool birds. You Z1 fellas with them ramp-over complex 28SC's. These 350-400's shared the same Mikuni design except that Honda used o-rings on the float bowls, Z1 and following designs of the VM didn't. We missed out. The Father and Son that own these have had them some 20+ years and haven't ran for just as long. I'm just a helping to bring them back. The Achilles heal of these was the "shoehorn" camchain adjuster under the crankshaft and sliders. These seem to be good though, gotta know how to adjust them helps too. He's got 3 more of them too, ha.