Possible Charging Prob

[allwx]

I went to start my 07 RSV this morning, all dressed and ready to ride. Starter sputtered, making sounds like dying battery. End of ride.

 

Bike has 33k on it.

 

So here're the symptoms that I've measured so far: Battery open circuit voltage is 12.3 after trying unsuccessfully to start the motor. I put it on my charger, and got a green light after five minutes. Open circuit v now 12.8.

 

I put the battery back into the bike and it cranked normally.

 

I measured the v across the battery with motor running. At idle I get 13.7. At very high engine speed (no tach) I get 13.9. It never gets above 14v, and only varies between those two points, 13.7 to 13.9 at any engine speed.

 

Book says should get above 14v charging, up to 14.5.

 

Does this below-14v output, and the fact that it varies only .2v, point to a stator or regulator problem?

 

Interestingly, I had a year-old battery fail, and also spit battery acid out into the battery box, some of which then dripped down onto my swingarm. It was a Westco. I suspected an overcharging situation then, but if anything, my charging output is lower than it should be. The new Yuasa that replaced it four months ago has worked flawlessly until this morning. I suppose the new Yuasa could be defective, but how odd to have two battery failures within four months? One suggesting overcharge, the other undercharge? Erratic Regulator?

 

I'm checking connections now. Thanks for all help.

[Guest]

Could be any number of problems, including a dropped cell in the battery. Have the battery load tested first. And while you are checking connections, drop the regulator/rectifier and pull the plug. Look into the plug openings and see if there are any burn/scorch marks, especially on the end holes. If there is then you may need to rewire the plug. The stator could also be weakening as well. But, like I said, it could be a number of things.

[allwx]

Thanks, Ruff. I had looked at the regulator plug a couple of months ago when I had the lowers off for some other thing I was doing. The plug and the contacts looked all but new, very shiny. No dirt inside. No signs of heating. Still, I may look at it again before I start taking side covers off the motor.

 

I looked at the ground connection on the crankcase right side. I'd never had that off. I was surprised at how much gunk was up under that connector. So that is now sanded off and shiny. Next thing I'm going to look at is the stator plug. I've never been in there.

[gibvel]

The charge voltage sounds about normal. At least that's about where mine sits.

 

After charging the battery let it sit for a couple hours then see what the voltage is. My guess is a bad battery cell. I've had it happen with a less than year old battery and my son-in-law had a bad battery less than 3 months after install.

 

NOTE: Just checked the service manual and it says the charging system should read 14V at the battery @ 5,000 rpm. not 14.5

Edited July 13, 2012 by gibvel

[allwx]

Well, I'm pretty close to that, then. I just went thru and sanded down the ground connection, as well as the connectors on the starter relay, and both battery terminals and cable connectors. Running at idle I get 13.88v. If I raise rpm up to near cruising speed v will rise to 13.95.

 

I was under the impression that voltage would vary more with rpm than what I'm seeing here.

 

I haven't looked at the stator cable connection yet. Need to pull the middle gear case cover to get at it. Good thing I'm close to an oil change.

[allwx]

I'm feeling better about my charging system. I disconnected the cable from the regulator and ohmed out the stator from there. The book sez to remove the case cover and measure directly at the coils. I got .7 om on each leg. That which is in excess of the spec is attributable to lead and cable resistance, so I'm probably OK. I also checked between ground and each leg, and got open on each leg. Then I ran the motor and measure the ac on leg, and got what I figure is normal output. About 26 vac at fast choke idle, and rising to around 80 vac at what I estimate is a highway cruising speed. All three legs seem essentially identical.

 

So I'm back to the battery. Tomorrow I'm going to buy a load tester. Seems like a good tool to have, and they are pretty cheap. I've been having enough battery problmes lately, a load tester will take some of the guesswork out of it.

[Brake Pad]

each battery has a born on date, stamped on a side. I just went through the same thing.

I checked all the fuses, found two on the right side cover, to have dark stains but not broken circuit, I replaced them a 15 & a 10, then I found one on the left side of the lowers, a #10 replaced that., checked all the connections, as I was in there. I even pulled the Harley lights off, and rewired the entire back end. I wound up replacing the Battery again. For me it turned out that the New Service Guy, was taking the new battery out of the box, pouring the acid into to it, and elementally, putting it on charge ( wrong answer!!!)

a battery should sit for 4 hours, being putting on charge. I had the shop wait a day, before charging. Geez, I'm happy to say no more battery issues.

[frankd]

I'm feeling better about my charging system. I disconnected the cable from the regulator and ohmed out the stator from there. The book sez to remove the case cover and measure directly at the coils. I got .7 om on each leg. That which is , a load tester will take some of the guesswork out of it.

 

You need to compensate your ohm meter readings by subtracting the meter lead resistance. Put your digital meter back on ohms, and short the leads together. I suspect that it'll read about .3 ohms. So subtract that reading from the .7 ohm that you measured for the stator leads, and that will give your actual stator resistance. Also remember, the value in the manual is @ 68 degrees F. If the stator was warmer, the resistance will read slightly higher. It sounds like your stator is good.

 

 

Frank D.

[allwx]

Good point about how the battery gets prepared. I prepared this one myself and followed the directions exactly. I bought it mail-order from Cycle Gear, so yes it could be stale. I'll look for a date stamp this morning.

 

I haven't had any battery problems in years. All of a sudden, I've had two of them die on me within the past year. And one of them even went so far as to spit acid out onto my bike, removing blotches of paint from my swingarm. REally P'd me O. It got me to wondering if maybe there's something going on with my charging system.

[bkuhr]

You need to compensate your ohm meter readings by subtracting the meter lead resistance. Put your digital meter back on ohms, and short the leads together. I suspect that it'll read about .3 ohms. So subtract that reading from the .7 ohm that you measured for the stator leads, and that will give your actual stator resistance. Also remember, the value in the manual is @ 68 degrees F. If the stator was warmer, the resistance will read slightly higher. It sounds like your stator is good.

 

 

Frank D.

 

Maybe not.

On the xj750 I had, book called for .7 ohms and I measured .4 ohms and thought 'close enough'. Turned out is was a bad stator, although his AC volt readings due appear to be proper.

I agree to figure out lead resistamce and subtract from reading.

[allwx]

You need to compensate your ohm meter readings by subtracting the meter lead resistance. Put your digital meter back on ohms, and short the leads together. I suspect that it'll read about .3 ohms. So subtract that reading from the .7 ohm that you measured for the stator leads, and that will give your actual stator resistance. Also remember, the value in the manual is @ 68 degrees F. If the stator was warmer, the resistance will read slightly higher. It sounds like your stator is good.

 

 

Frank D.

 

Thanks, Frank, yeah that's the way I did it. I wouldn't have considered lead resistance if I hadn't read it mentioned by Joe in another post on another thread. My leads shorted actually came up at .4, though reading was erratic. I also figured there'd be a little more R due to the length of the cable and connectors. The book spec seems to be based on measuring right at the coils on the stator. Good point on engine temp. I'm sure mine heated up a bit during testing. The alternator side of the motor always seems to get hot faster.

[allwx]

Maybe not.

On the xj750 I had, book called for .7 ohms and I measured .4 ohms and thought 'close enough'. Turned out is was a bad stator, although his AC volt readings due appear to be proper.

I agree to figure out lead resistamce and subtract from reading.

 

Near as I could tell from shorting the leads on my TekPower DT960 is 0.4 ohm. The reading is erratic, though. I accepted the .4 reading because it stayed at .4 longer than any other number. When I measured the R across the legs at the cable end, the reading flickered a little between .7 and .8, but tended to stay on .7 most of the time. That gives me a value of between .3 and .4 ohm, and each leg was the same. If it was a little higher than .3 I attributed to engine heat and the cable length between the regulator and the stator.

 

I also realized that the lower than expected voltage at the battery I measured with engine running was because the battery was low. As the battery charges up the voltage measured across the terminals rises. When I check the alternator output across the battery, with a more fully charged battery, I get right at 14v, maybe just a hair less.

 

So I think my charging system is OK. Next step I'm taking the battery in to Cycle Gear. I bought it mailorder from CG, and the local store says they wiill help me with the warranty, assuming it is bad. I'll let them load test it and see.

[allwx]

It was the battery after all. The local Cycle Gear store took it on warranty. I got an off-brand chinese made looks exactly like the Yuasa, and so far it works great.

 

Thanks for suggestions, and as always the Forum is a necessity of life, couldn't live without it.

[playboy]

? did they not have the Yuasa in stock. Don't understand why they didn't replace it with what you purchased from them.

[allwx]

? did they not have the Yuasa in stock. Don't understand why they didn't replace it with what you purchased from them.

 

Well, I didn't argue with them, mainly because the battery they gave me is obviously made in the same factory. The guy brought out a BikeMaster brand, and it was identical in every visual respect to the Yuasa, except made in China, whereas my failed Yuasa made U.S.A. Interestingly the Yuasa was a YTX20BL, the Bikemaster was a BTX20BL, and the one I actually took home is a CTX20BL. I didn't like the look of one of the terminals on that Bikemaster battery, so the guy brought me another one, out of a differently branded box, also Chinese made, and with a slightly different form factor than the Yuasa.

 

In any case, another reason I don't argue about this type of thing is because warranties are always written such that substitutions can be made as deemed necessary by the seller. As long as the substitution is reasonably equivalent, there's nothing to complain about. And especially with batteries, which I assume that pretty much all of them are being made out of the same factory in China. I liked the U.S.A made on my dead Yuasa, but it is, alas, dead.