Bad R&R or Bad Battery?

Folks, I need some advice here. Four days ago I did the test for voltage at battery terminals with bike running. Prior to test I had charged the battery overnight. The battery cells 1 & 2 were just a tad below minimum line which I topped off with distilled water before charging. The other cells were exactly at mid-point between min and max.

When I put the multitester probes on the battery terminals with the bike at idle, the needle went straight to slightly below 15 volts. When reving the engine to 4,000 rpm the needle didn't move but stayed at slightly below 15 volts.

Today I checked the battery out of bike, and it had dropped to 5 volts just sitting out of bike.

My question is this: The battery is an older YUASA (el cheapo), how old I don't know - was in bike when purchased. Could my test reading be the result of a dying battery, considering the fact that it dropped 7 volts in four days not being used.

Or is the test indicative of a failing R&R? The R&R tested positive when I did the continuity test referenced in the factory manual. Appreciate your help!

With the battery fully charged again and NOT connected to your bike... what are the results the next morning?

If the voltage is low again and the battery fluid IS boileded away, then you most likely have a charger problem.

If the voltage is low again but the battery fluid is not boiled away, then you most likely have a battery problem.

If the voltage is OK, then you have a circuit on or a short in your wiring or even in your ignition switch.

Best of success.

Norseman wrote:

... charged the battery overnight...
Today I checked the battery out of bike, and it had dropped to 5 volts just sitting out of bike....

Thinking battery is shot.

If me, would consider replacing with "maintenance free" version, a little more expensive, but well worth it in not having to goof around with pita fluid level maintenance.

Need any help with checking alternator output and voltage regulator??


P.S. Got maintenance free version at AutoZone -- and if must "order" only take a day or two.

Post edited by: Patton, at: 2007/09/12 21:29

Wow, those were definitive and extremely helpful comments, Bill_Wilcox and Patton. I will charge the battery again tonight, unplug it but leave it sit for 24 hours, then test the voltage. That's cool - I'm waiting for my new Dyna coils I ordered from Z1 today anyway.

Now, I did fully charge it four days ago, and only used it to start engine once, then removed it and let it sit in my garage unconnected. Like I said, it dropped 7 volts. However, fluids were not reduced at all, and prior to that over the course of two months of running with my misfiring issue, the fluids didn't diminish. I remember seeing that slightly lower level on cells 1&2 a long time ago, just didn't get to it while trying to identify and fix other problems. My point is the fluid is not boiled away, which seems to indicate a bad battery, per Bill's comments.

Per Patton's comment; I called AutoZone and they do carry the maintenance free, but do not have it in stock - I'll order one after verifying the battery problem.

My misfiring seems to make sense now; Strong battery with weakened coils = may still run OK. Strong coils with weak battery = may still run OK. Combine original/old weakened coils with weak/bad battery = runs like crap with misfiring.

So, with new coils and new battery hopefully my search is over (together with the many redundant and annoying posts you all have been annoyed by):S

Thanks.

If the battery truly measures 5 volts with no load, then it is a doorstop. Even a dead battery will measure close to 12v. Less than 11v means it's close to being scrap.

Just a thought, since you will be doing all this good stuff, you may want to do the WG Coil Re-powering Mod. to make sure you get all the voltage to the coils you need over the long term. Why revisit this again later? This mod was great for me!

Best of success.