650 stopped running mid-ride

[tpersin]

Hi All,
new forum member here with a tech question (great stuff on these forums, so grateful!) that has me scratching my head.

I recently got a 79 CB650. It's a runner, but I'd like to do some work on it for both cosmetics and performance.

I'll lay out the issue in bullet points...

1. The bike was running ok, but a little rough. But I had had it out on several short 10-15 mile rides.
2. I took apart the carbs, cleaned them (they were already pretty clean from the previous owner), and bench set them.
3. The bike ran a LOT smoother on a few short spins around the neighborhood (1-2 miles each).
4. I replaced the old, dying batter with the appropriately sized Shorai Lithium Battery (LFX14A5-BS12).
5. Tested the battery before installation and it read 13.3V.
6. Took the bike out on a 3.5 mile spin and it stopped at about 1.75miles.
7. The bike was running great and then it just stopped. The engine lost power and it quit.
8. Pressing starter button - nothing happened
9. Field check: the Kill switch was in run mode and all else was in operable mode --checked mulitple times.
10. Yep, the bike had plenty of gasoline.
11. I was able to bump start it on a convenient downhill.
12. Bike ran for about a half mile and quit.
13. Would not bump start. Starter button did nothing.
14. Pushed the bike home (a mile of pushing... )
15. Got home the battery read 5V.
16. Checked the battery the next morning and again this evening and it read 11.65V.
17. Just tried to start the bike and small crank and then nothing.
18. Battery check after reads 10.5V.

thoughts appreciated!

[Folsoml]

The charging system in these old bikes is notoriously bad. Your's sounds like it is gone. Fully charge your battery, then start it up with a multimeter hooked up to the battery. Rev the engine to about 3000 RPMs. Your multimeter should read around 14 volts or so. If it does not, which I suspect it won't, your charging system is bad.

Check my signature for links for common problems. There are several helpful electrical system links.

[MEHall]

A Shorai Lithium Battery (LFX14A5-BS12) is a bad choise as any Lithium Battery is'nt made for a 79 - 80 bike of this sort.
Folsoml is quite right here and i may add that the electrical system is made only to work in berfect balance with a 12 mAh lead acid battery. The problem is that the electrical system wont cope with what a litium ferro battery needs in terms of charging.

I hope that info will shead alot of light in your charging problem.

[tpersin]

Thanks for the info guys - appreciated!
I'll check the charging system this evening.

[MEHall]

The trouble with batteries that is not Lead acid and the quite weak charging/electrical system of the CB 650 is that it may not be able to charge the non lead acid battery correctly.
The main trouble is that the wireing in the rotors can get damaged by the engine heat and the rotation of the engine do the damage worse.
One solution is to get a new and improved rotor that can cope alot better with the engine heat, but that dont mean the effect of the charging gets better.

That is what i've learned the hard way.