2002 Heritage with 55,000 miles having fuel issues flowing at low RPM's

[ThunderRogue]

the 1995 flhtcui the battery was showing full charge 13.4 volts and would turn over the motor with the bypass button on the starter. but if you used the starter button on handle bars it would not start. the only thing I could guess was that the electrical load on the ignition was just enough to not power the starter relay fully with the extra electrical load. which lead me to think the battery had a weak cell. it was driving me crazy until I dropped a new battery in.

Many times the battery will charge full but when placing a demand on it that shows the bigger voltage drop. And in your case (as with most) a dead or shorted cell proven by a load tested.
As I mentioned, always pull the battery and have it load tested first when trying to solve starting problems. Also made sure all contact points on all the cables are clean and tight.

 

[Justjake]

A quick and easy load test @ home, hook up your voltmeter @ the battery, observe the reading when trying to start your bike, if voltage drops below 10 volts, your battery is on the way South

 

[ThunderRogue]

A quick and easy load test @ home, hook up your voltmeter @ the battery, observe the reading when trying to start your bike, if voltage drops below 10 volts, your battery is on the way South

While that is good advice, there can be marginal differences. Bosch say's lower than 10 volts is acceptable in the lower ranges at 9.6 volts. So I wouldn't trash a battery that's reading 10 volts.
One of these hopefully will open.

Adobe Acrobat

acrobat.adobe.com

 

[Jeff Klarich]

While that is good advice, there can be marginal differences. Bosch say's lower than 10 volts is acceptable in the lower ranges at 9.6 volts. So I wouldn't trash a battery that's reading 10 volts.
One of these hopefully will open.

Adobe Acrobat

acrobat.adobe.com

That's news to me, every battery I had that dropped in the 10 range during a load test was junk or will be in short order. I wouldn't trust a battery that drops to a 10 or lower during a load test, been stranded before and it's not a good feeling.

 

[biscuit]

That's news to me, every battery I had that dropped in the 10 range during a load test was junk or will be in short order. I wouldn't trust a battery that drops to a 10 or lower during a load test, been stranded before and it's not a good feeling.

Think you hit that right on the nail Jeff.

 

[ThunderRogue]

I'm not here to argue with anyone. And I'll not disagree with the state of charge biscuit has provided.
I urge you to search the web with the question regarding acceptable voltage drop during cranking. You'll see several that state exactly what I have said. Here's another.

How to test a motorcycle battery - RevZilla

How do you know if your problem is really your battery? How do you know when it's time for replacement? Here's how to test.

www.revzilla.com

 

[Jeff Klarich]

I'm not here to argue with anyone. And I'll not disagree with the state of charge biscuit has provided.
I urge you to search the web with the question regarding acceptable voltage drop during cranking. You'll see several that state exactly what I have said. Here's another.

How to test a motorcycle battery - RevZilla

How do you know if your problem is really your battery? How do you know when it's time for replacement? Here's how to test.

www.revzilla.com

No one's arguing with you ThunderRogue just speaking from experience. I personally would not trust a battery that would drop as low as 10 during a load test on a fully charged battery.

 

[ThunderRogue]

No one's arguing with you ThunderRogue just speaking from experience. I personally would not trust a battery that would drop as low as 10 during a load test on a fully charged battery.

That's fine. I mean really what's 0.4 volts right?

 

[Justjake]

Most modern day Harleys ignition systems will not fire when battery voltage drops to 10 volts and continues to drop, that is the sure fire way to poor man load test a battery

 

[biscuit]

I'm not here to argue with anyone. And I'll not disagree with the state of charge biscuit has provided.
I urge you to search the web with the question regarding acceptable voltage drop during cranking. You'll see several that state exactly what I have said. Here's another.

https://www.revzilla.com/common-tre...HVZybAx1X7wQQrCMHXjPpp5xdqeAhWs9yD0VQDlE1vRuN

Voltage drop during cranking is to be expected. The same way your house lights may momentarily dip when you turn on a biggish load, But will go bright again when the load ( inrush current or voltage) disappears.
Same with the 12vdc on the bike. May drop from 12.5/12.6vdc to a low of 12.4vdc.
It’s what it rises back up to that’s important.
If it won’t go back above the low 12 volts then she be toast baby.
Not to be trusted.
Unless you carry one of those Battery Jump-Starters.