1989 FJ1200 Not holding/building a charge

[racerrad8]

Dropped from what reading?

You should have the same voltage at both alternator wires when the bike is running and the should be 14V , and really up to almost 15 at 5k.

If you don't have the same voltage at both wires then something is wrong.

Randy - RPM

[sooptime]

Dropped from what reading?

You should have the same voltage at both alternator wires when the bike is running and the should be 14V , and really up to almost 15 at 5k.

If you don't have the same voltage at both wires then something is wrong.

Randy - RPM

Just went out and rechecked. 12V at idle at the battery. Revved to 5k and still 12V.

[sooptime]

Will check it at the alternator as well tomorrow. Thanks for the help Randy.

[sooptime]

I checked voltage at the battery and each side of the connector. Today the reading was 11.4V everywhere, whether at the battery or connectors or at idle or 5k rpm.  I replaced the connector with insulated spade connectors and no difference. The red connector was slightly melted and brittle so prudent to do it anyway.

[sooptime]

So it's another season and I need to get out on the bike. Time to get the issue resolved.

New battery, new regulator, wiring issue per threads here replaced, 12V reading no matter what the rpm and less as bike runs. It's running off the battery.

So it sounds like a rectifier. What is the best replacement?

[fj1289]

http://www.fjowners.com/index.php?topic=15432.0
Download the PDF of the 1100 manual from this link. 

PDF page 224 (service manual page 6-21) is the flow chart for troubleshooting the charging system. 

Post up what you find at each step - there could be a couple items to check prior to spending $$ - such as the connector already discussed and cussed, the voltage "feedback" wire that lets the voltage reg know how much voltage it's putting out, and others I'm sure. 

[sooptime]

http://www.fjowners.com/index.php?topic=15432.0
Download the PDF of the 1100 manual from this link. 

PDF page 224 (service manual page 6-21) is the flow chart for troubleshooting the charging system. 

Post up what you find at each step - there could be a couple items to check prior to spending $$ - such as the connector already discussed and cussed, the voltage "feedback" wire that lets the voltage reg know how much voltage it's putting out, and others I'm sure. 

Great info. Thanks.  I just need to find the time again to pull it apart.

[sooptime]

I found a reasonably priced replacement alternator on eBay. I just installed it. Voltage at battery with bike off is 12.25. Battery isn't fully charged off my charger. At idle I am getting 12.7 to 12.90 V. When revving, 14.6V no matter the rpm.

These numbers are better than the nothing that I was getting with the old unit. It's now charging.