[1982CB900]

I have an 82 CB900C. It was running fine, sometimes took awhile to warm up but I couldn't expect much for a bike from 1982. I had previous small problems with the battery/starting. I would have a full charge, go for a ride about 10 minutes, park it and then when I would come back it wouldn't start with the starter but I could bump start it. Thought that problem went away.

One day I was just riding on the freeway, about 20 minutes into my ride the bike starts to stutter and just dies out. Wouldn't start up again for about 30 minutes and then when it did start it wouldnt idle and sounded really rough.
Every now and then I can get it to start but have to hold full choke and a little gas just to get it idle roughly at 1000 to 1500 for a minute or two and then it dies. If I give it more gas to get higher RPMs, it dies. not enough gas and it dies. Always wants to die.

Any suggestions on where I should start?
Fuel tank is clean and has fresh 91 octane.

Thanks!

 

[MONI]

I am not one of the great mechanics we have on the Forum but...the next time this happens open the gas cap and see if there is a suction noise. If not, there may be a vent that is blocked. That happened to a friend's bike. I hope it is that simple for you.

 

[1982CB900]

Thanks Moni. I will definitely try that next time.

 

[cmonSTART]

Based on what you said the first thing I would look at is whether the battery is charging while the engine is running.

Measure the voltage at the battery with a voltmeter.

Engine off should be about 12.5 volts (no less).
Idle should be around 13 volts.
With some revs the battery should measure about 14.1 volts.

If you aren't getting these measurements it's time to look into the charging system and see what isn't working.

Also take a look at the main electrical connections at the battery, as well as the main ground on the frame, wherever that is.

 

[Critter]

you need 3 things:

Fuel
Air
Fire

Check all three one at a time.

 

[Dodsfall]

Based on what you said the first thing I would look at is whether the battery is charging while the engine is running.

Measure the voltage at the battery with a voltmeter.

Engine off should be about 12.5 volts (no less).
Idle should be around 13 volts.
With some revs the battery should measure about 14.1 volts.

If you aren't getting these measurements it's time to look into the charging system and see what isn't working.

Also take a look at the main electrical connections at the battery, as well as the main ground on the frame, wherever that is.

That would be my guess as well.