Vf750F runs for 5 min then motor and electrical system go dark.

Hi. I'm new to the Forum. I have joined because my 1983 Vf750f is having some problems. I rode over to a friends house the other day and everything was fine. When I was about to leave for home I turned the key on-everything was fine- and hit the starter button. As soon as I pushed the button everything went dark. The bike never even attempted to crank. I was short on time so I called my brother and we loaded it up on the trailer. Now I that I have some free time I would like to get it working properly. Yesterday I took the battery to Advance auto hoping it could be as simple as a bad battery. They said the battery is fine.. Once home I re-installed the battery and tried the bike again. Nothing.. I then jumped the bike off my car, and to my surprise, the dash lights came back on and the bike started. I figured I had solved my issue so I took the bike around the block. Just as I neared my house the lights dimmed and the engine ran rough and died. Everything was dark again, no matter if you turn the key on or off. Has anyone had any similar experience with their bike?? My best guess is I may have a short somewhere.. Thanks!!!!!

 

Closely inspect your main fuse. It is located on the solenoid next to the battery. Sounds like it may be cracked. Even if it looks ok, take it out and inspect.
I would recommend obtaining a newer style blade type inline 30A fuse. Crimp on some small eyelets and bolt it up where the fuse link was. That way a replacement fuse is easily obtainable from an auto parts store.

After that, could be a failing ignition switch? If you have nothing the next time you check it, see if you get a taillight on the "park" setting.

 

Captain 80s,

Thanks for the help. I have taken out the main fuse and it looks ok. I'll attach a picture so you can see it. Tomorrow I will do what you said and retrofit a new blade type inline fuse.

 

unplug the connector on top of the start solenoid to check for melted or burned wires. i'd suspect that your charging system is kaput.

 

had a similar problem and turned out to be the right side switch block. the headlight switch would short out the whole bike. could have lights on but no dash lights as a temp fix. Even wrecked 2 starter solenoids getting it sorted. Changed out switch block and bike is sweet as now.

 

ok.. So I have replaced the main fuse with a modern substitute. I disconnected the battery, charged it, and hooked it back up. The bike started right up! It seems to be that disconnecting the battery is almost a "reset" button. I decided I would change the oil. I happened to have both side covers off when I started the bike post-oil change. To my surprise I heard a clicking sound. I did some searching and located the sound coming from the regulator. Any idea why it would be clicking? I'm assuming it is a sign of a faulty regulator.

Thanks!!

 

What ????????? Do electrons click ?? No, voltage regulators never click, so must b somethin else, like a fuel pump maybe.

 

Ok... I have no clue whats happening. I started the bike today let it warm up and run for about half an hour. no issues... Did it fix it self?? also-- I was wrong squirrelman. It isn't the voltage regulator clicking. Its probably the fuel pump like you said. Is that bad?

thanks!

 

NOT BAD as pumps always click when they're actively pumping but should stop when carbs are full. I don't think it's good for any bike to sit still while running for more than about 10 minutes.

 

ok great! I'm still trying to figure this dang thing out. anyway.. in the meantime I will be replacing my front fork seals. They are completely shot.