Battery, or alternator?

[MarlboroMan]

Hey,

Came out to my bike this evening, got on, turned the key, hit the starter, and nothing happened - no lights on the bike, so I assume I left the ignition in park instead of lock.   Got it jumped, left the cables on for about 5 minutes, then unhooked them, and got a small drop in revs.  Didn't think much of it, finished letting the bike warm up, then went out on the road.

I got about 1 block before the engine started backfiring - it was so bad, I had to pull over and turn off the bike.  Now we're back to no lights on the dash.

I went and got the battery replaced (hadn't done it since I got the bike, and it was cheap anyway).  My question is, is it more likely a faulty battery, or do I have a bad charging system on the bike?

[GRU]

I went and got the battery replaced (hadn't done it since I got the bike, and it was cheap anyway).  My question is, is it more likely a faulty battery, or do I have a bad charging system on the bike?

so what happened when you put in the new battery....

if you chareged the battery a little and went for a ride, it could have been the bad battery or the alternator because if the battery was very bad than you would have to charge it for a while not just jump it and go for a ride....but it sound more like a bad alternator because if the altarnator was good you should be able to ride all day on a bad battery....


when i bought my bike it had a dead battery that was charged 3 time in one day (the day i went to look at the bike) and when i got the bike home i drained the battery once again...then when i fixed my bike and tryed to start it the battery was dead so it wouldn't turn over...then i jumped the battery and went for a ride....now my battery is still good


so i'm thinking you got a bad alternator

[MarlboroMan]

I threw in the battery, and have ridden the bike since (about 60 miles) without any problems.

[tarascio]

Had trouble starting the bike on Thursday morning but eventually did.  Rode to work but when I tried to start it 12 hours later afterwards, it won't.  After jumping it, I rode home.   That night, I disconnected the negative lead, in case, something was draining the battery.   Sure enough, the bike started right up on Friday morning.  rode to work without any problem.  Disconnected the negative lead again so I suspect I'll be ok.   I hope to investigate the drain this weekend and would appreciate any feedback.  Thanks.

[MarkusN]

Careful when jump-starting from a car. I have heard reports that doing this with the car's engine running may damage the voltage regulator of the bike. Which might have contributed to the problem mentioned here.

Next time you drain the battery, try push-starting the bike. Works like a charm for me, and does away with the risks of jump-starting.

[GRU]

I threw in the battery, and have ridden the bike since (about 60 miles) without any problems.

so what do you think the problem was   ...if your old battery was just drained then when you restarted the bike your alternator should have charged the battery (but didn't)

i still think your alternator may not be charging the battery enough and over time the battery you have now (new one) will be draind too, so it would be a good idea to test your charging system

[Kerry]

Rode to work but when I tried to start it 12 hours later afterwards, it won't.  After jumping it, I rode home.   That night, I disconnected the negative lead, in case, something was draining the battery.   Sure enough, the bike started right up on Friday morning.  rode to work without any problem. [...] I hope to investigate the drain this weekend and would appreciate any feedback.

You may have fallen prey to the good old "Park Position" on the ignition switch.  When you turn the bike off you can lock the steering by turning the bars to the left and turning the key to the LOCK position.  But if you're not careful you can easily turn the key a little further, to the PARK position.

In the PARK position the taillight is illuminated, even after you pull the key out.  This is easy to spot at night, but hard to notice in the daytime.  Next time you get off the bike, see if it's possible that you turned the key to PARK that one time.