Topic: '76 CB400F starter woes...any help would be much appreciated!!

[jeff kushner]

OK guys, it’s been a while since I’ve been here but I ran into an issue with my ’76 CB400F. I have a fully charged battery, it reads 12.8V after removing the charger for the entire night.

Lights, blinkers all function normally however when I engage the starter, it barely spins, even if I use a screwdriver to connect the terminals of the solenoid directly. It may half-heartedly spin once then stop or it may not spin at all. Bike in neutral, clutch pulled in….makes no difference.

I have removed, cleaned and reinstalled the main ground from the battery at both the battery and at the engine, same with all three heavy and both light wires to the starter solenoid. I removed the sprocket cover and disassembled, cleaned and reassembled the starter wire and all the other smaller wires while in there. I also removed, cleaned each terminal and reinstalled both multi connectors (one under each side cover) and  or course the battery connectors

Still no difference.

Finally, I connected my car battery to my bike as if to “jump start” it and the starter whirled to life instantly starting the bike.

I removed the car jumper cables….ran the bike while checking the voltage…..15.06….ran for 20 minutes or so and shut it off and tried to restart….starter solenoid acted like it was barely alive again but when I kick-started the bike, it started instantly.

I am an engine guy and restored this from junk…..but I’ll be the 1st to admit I’m weak with electrical issues….any help would be really appreciated!!!


Thanks guys,

Jeff

[strynboen]

thek your battery for full amps flow..12 -14 volts are not a garentie for it can pump amps..try to turn full light on..and try to aktivate the stater..if all lights goes even in instrument panel(collor lights) ..the battery are dead
 a auto elektro shop have a test app "toaster" vho easy can test the battery..so spend a test..and be shure on the battery helse

[calj737]

Cranking amps of the battery is my suspicion. When you flip the key on, what voltage do you get at the battery directly?

[chopper nut]

hook volt meter across battery and hit starter if volts drops to 6 volts or lower get a bettery

[NobleHops]

Rebuilding that starter is a $20 project if it turns out to be the issue. Hit the build thread link in my signature - I detailed it there.

N.

[jeff kushner]

Thanks guys, I knew that you would come through for me. I did as suggested and connected my meter and as soon as I flipped the key on...voltage dropped to 8.3V...you would have thought that after as many restorations as I've completed, I would have thought of that but then again, that's why these forums are so good...they help guys like me that can't see the tree because the forest is in the way!

N,
I removed the cover but was afraid to remove the starter because I wasn't sure how it was connected to the starter clutch as many bikes are....I found a parts manual and saw that it just slips out so I may go ahead and do that while I staill have the shift linkage removed.

I'll post up after I get a new battery!

Thanks again guys,

jeff

[strynboen]

alvays good to vask the komutator and brushes in fuel..blow it dry vith kompresed air..give the bushing/berings some grease..and polish the komutator vith very fine sandpaper..and klean up betveen the lamells use a nife.or .hacksav blade

[jeff kushner]

New battery, all fixed. Funny but the battery was only 18 mos old, was always put on trickle and when charging on the regular charger, bubbled in all cells yet was bad. Installed new battery and spun over nicely!

Thanks again for your help guys.