In my endless '87 CBR 600F saga, there may be a charging system issue. I ran the tests in the manual and it fails the leakage test. The manual says I should see 8V from I connect a meter between the negative battery post and the ground wire but I see 12.4v (the actual battery voltage). Is the 8V what is expected and should I now be chasing wiring harness issues and/or regulator issues?

 

Not sure that means much. You should do the charging system tests if you suspect a problem. The RR is a shunt to ground system. The factory RR is a fail point, but if charging tests check out I would leave it alone. If there is a problem, replace it with a Mosfet kit.

 

The leakage test is charging system test from the manual. I put in a voltage gauge so I can see charge/drain while riding. I also noticed a pretty big resistance from the ignition switch which would sometimes be as high as 5-6 ohms. I decided to put in an ignition relay to avoid this resistance being inline with the electronics on the bike. I am not going to worry too much about this 8v vs 12v thing. Can you point me to the MOSFET kit you describe? I would love to get more consistent voltage/charging.

 

https://www.ebay.com/itm/UNIVERSAL-M...4383.l4275.c10

 

Thankyou. I will look into it.

 

"Well my ride was enlightening too. After my son had issues restarting at a gas station I had decided to install a volt meter in the bike. Today my ride started out pretty good; lots of power and the engine was pretty smooth (not perfect, but not bad for an '87 with a used carb that I haven't tuned to the bike yet). Two minutes in I started to feel some hesitation pulling out of lower RPM, followed by a backfire in the same condition. When I got to the next stop light, my little volt meter showed 10.4 volts ... ouch. U-TURN and back to the garage. When I get it wound up; it sounds pretty good; but the minute the RPM drops and I have to accelerate again, it is bad as the battery starts to die. So this seems to indicate it does charge, but the charge isn't really helping the battery. Put the bike back on the battery tender and the battery starts to recover again. So I was going to swap the regulator (just cause I am sold on the MOSFET conversion to get into the 2000's), but I would not expect a battery to go tilt after 2-3 minutes of riding even if the charging system was completely disabled. Do you guys agree? Advance auto tested this battery and claimed it was ok; but this doesn't seem ok to me. At this point I believe the intermittent nature of my problem has been due to low voltage. I start it up and go for a ride around the lake; no problem. My son starts it up and sits and idles for 5 minutes and practices shifting up from a stop; and BOOM, the bike starts to lose it. It all makes sense."

You should see 13-14V between the battery poles when idling, and a higher voltage at 5000rpm, that means it's charging.
Battery should read above 12V with engine off.
You'll have to go through the stator and rectifier trouble shoot check list in the manual, until you understand it.
Don't ask me for advice, because I have re-read that chapter myself everytime I have a charging issue.

 

Yeah. I ran the troubleshooting section already. Stator resistance tests are good and no short to ground. All other tests pass also except for this 'leak test' that shows 11.70v vs. 8v as stated in the manual. No one was able to help me understand if 8v is really expected and I don't really understand where 8v would come from.. The fact that the battery can't hold 12v with the ignition on and engine not running for more than 10 seconds leads me to believe the battery is sick. If I disconnect all lightls, it holds 12v for a minute if I am lucky. Battery is a DURALAST dated 5/18. Note that these autozone batteries get terrible reviews.

 

Liquid acid battery? Those last 2 years at best, just a 3 month warranty . A BikeMaster AMG is less than $50, 1 year warranty.

OK, I just did Test 2 and 3 on my bike, failed both. Got the full battery reading 12.4 V on test 2, and only 12.4 on test 3, voltage dropped to 12.2 V at 5000 rpm.
System is not charging. Disconnected the battery for now.
Don't have time to continue today, I'm headed for a 4:PM til dark Track Night, will be riding my Suzuki.

 

I put a bikemaster GEL in a Buell we had. It seemed fine. This battery is a Powersport AGM battery that does in fact have a 3 month warranty. It is frustrating that it was tests as GOOD which sent me on this wild goose chase. Have fun at the track.

 

Sounds like your RR is on its last legs.