Battery not charging on my Honda VT250Z

[thiucumaran]

Well, a few months ago, I was having some trouble starting my bike in the morning. This was before winter started, so this was kinda odd, but I would just roll it down a slope just outside my apartment and get it started and go to work on it. Since my office is just 4 km away, I wasn't having any other problems, so I figured it must just be some small problem which will just go away

One day, I went to a mechanic's shop, which is about 25 km away. As I was coming back in the night, I started to notice, about 20 km into the journey back home, that my headlight was noticeably dimming whenever I pressed the horn or turned on the signal indicator. I also noticed that the headlight became noticeably brighter when I revved up the bike, so I knew the battery wasn't charging.

The next day, it just absolutely refused to start. I took out the battery, only to see that it had got swollen, just 6 months after I bought it.

I bought a new battery and took the bike, yesterday, to a mechanic who is about a kilometre away from my apartment. He said that the CDI was toast, so I went and bought a new one.

He then said that the rectifier seemed to be overcharging and that the CDI went toast because of the rectifier overcharging.

I went ahead a bought a new rectifier. After the mechanic fitted it in, we switched on the bike and the headlight was working fine, as was the signal indicators and everything. Since i rode short distances (less than 5 km at a time) during the daytime yesterday, it was working fine. However , I noticed that, as soon as I started the bike, it would switch off within a second unless I revved it up a bit. It didn't seem like a huge issue, so I let it be.

In the evening today, when I took my bike out, I started to notice the light dimming again when I honked or put on the signal indicator. I also noticed that the horn wasn't as loud as it usually was. Since I was a bit far away from home, I continuously kept revving my bike when I was in traffic, so that it wouldn't switch off, as I was worried that I might not be able to start it again.

As I got to my destination, which was 10 km away from my apartment, the headlight had dimmed to the extent where it was pretty useless in dark roads, and as I slowed down to park the bike, it stopped, and wouldn't start again. I left the bike in the parking lot.

When I came back after about an hour, it started again, but the lights were gradually dimming and , after about 7 km, totally gave up on me, despite my continuous revving.

I then started pushing my bike back home. With 1 km to go, another biker stopped and offered to push my bike as I started it from 3rd gear. Thankfully, it started, but I didn't switch on the headlight, even though it was night, as I was worried the battery would die on me again.

I managed to get it back to my apartment and, after parking it, I left the engine on for about 2 minutes, and it didn't die.

Since I have a new rectifier and CDI in place, what other reason could there be for the battery not charging?

Would really appreciate the advice because I'm worried to take the bike out because I don't want to have to push it around, since it's REALLY heavy!

Thanks in advance![/list]

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Faulty stator coil? You can check the coils by measuring resistance between certain wires coming from the stator. I did this when mine failed on my race TZR250. One resistance was way too high, so I sent it away to be rewound.

You'd need a manual to get the resistances and wires to check though.
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TZR250 2MA road, TZR250 1KT road, TZR250 2MA race, TDR250, YZF-750R Boost colours.
Jaguar S Type 3.0 V6 Sport R, VW Transporter T5 GP LWB Shuttle 140ps DSG.

[andys675]

sounds like the stator

it will have been the regulator/rectifier at fault, it regulates the output of the stator, if it goes faulty the stator can put out too much power which boils your battery (as evident) and the stator will work flat out until it burns out and is no longer able to charge the battery and putting the headlight on is too much of a drain on the bike affecting running
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Some people feel the rain, others just get wet.

[jaffa90]

How old is this Honda?

[Pete.]

Charge the battery, then start the bike and check the charging voltage. If voltage isn't rising with revs then it's not charging. Un-plug the reg/rec from the stator and check the AC output at the loom plug for the reg/rec. If you're getting anything like 60-70v AC at around 4000rpm then the stator is working. If not the stator is toast. Make sure your meter is set to AC when checking the stator output.

If the charging voltage is low but the AC voltage is right on all 3 phases check the charging voltage right at the reg/rec plug black and red wires (with the unit plugged in and the engine running. If it's getting 14.5 or so volts there you have a wiring fault. If not the reg/rec is toast.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[thiucumaran]

Thanks for the replies, everyone. I'm a real nOOb when it comes to the technical side of motorbikes, so all this is new to me.

In order to do the checks on the rectifier/stator coil, would it be a good idea to get a multimeter? Considering the number of of times I've been having issues with the battery not charging, would it be worth it?

I'll anyways be going to the mechanic and getting these checked out, so thanks for the suggestions.

Jaffa90, the bike is 13 years old, but I got my hands on it about 2 years ago.

[Pete.]

Yes, a multimeter is essential.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[The Shaggy D.A.]

[thiucumaran]

So I went to the mechanic again today. He hadn't given the connection properly from the rectifier to the engine, which is why it wasn't charging. It seems to be doing fine for now.

Thanks everyone for the help, much appreciated. I have a LOT to learn about the internal workings of my bike!