so im looking at this older honda cbr and the guy says it needs a new battery and a that its sat for a month but he just rode it 70mi yesterday and it rode fine but the battery was dead when it got back, doesnt that mean that its not holding a charge? i forget the name for a motorcycle "alternator". any opinions? thanks.
2007-07-10 13:48:31 · 9 answers · asked by Anonymous in Cars & Transportation ➔ Motorcycles
Check the battery voltage with the bike not running, if its less than 12 volts, charge it up for 24 hrs using a trickle charger, unhook the charger, test again, if its still not 12 v then battery is bad. If it shows 12.5v after charging, start up the bike, check again, if its now under 12v, the charging system is bad. If its about 13-14v battery and charging system is ok.
After charging a battery, it should hold a charge for a month or so at a minimum (if it has not been ran).
2007-07-12 03:54:24 · answer #1 · answered by Jim F 2 · 1⤊ 0⤋
Yes, it quite possibly could be the battery. It could also be the charging system. Most Japanese bikes use a type of alternator and a rectifier. The rectifier is usually located under a side panel, usually on the left side of the bike. It is made of aluminum and has fins on it, for cooling. If you have access to a volt meter, with the motorcycle running, put the red test lead on the positive side of the battery and the black lead on the negative side of the battery. Make sure your voltmeter is on the 20 volt D.C. scale. It should read about 13.75 to 14.5 volts.
Still keeping the leads on the battery, rev the engine to around 2,000 r.p.m. You should see a small increase in the volts read.
If it doesn't increase and it reads less than 13.75 volts when idling, you could have a charging problem. Now, shut the engine off, leave the key on and the headlight on high beam. Hit the turn signals and beep the horn. Do the same thing with the test leads on the battery. If the voltage drops rapidly to below 9 volts, the battery is junk. Replace the battery and try this test again. A faulty charging system can kill a battery to a point where the battery will no longer hold a charge. So, if you want to "cut out the middle man", replace the battery first and then check the charging system. A welded plate inside the battery (happens very often in motorcycles) will also throw off the whole charging system, including the test just described.
2007-07-10 21:06:37 · answer #2 · answered by k.t. W 3 · 0⤊ 1⤋
Battery is dead and won't hold a charge. Charging system is working as he rode it for 70km and made it back ok.
70km is not going to charge any battery.
Have him buy a new battery as a condition of the sale and have the bike checked out by a bike mechanic as there may be other issues with the bike.
Ride Safe and Good Luck!
2007-07-11 23:18:57 · answer #3 · answered by JustAnotherJoe 3 · 1⤊ 0⤋
When you leave a battery alone for a month, I mean not riding the bike or anything, it gets completely discharged. If you leave it for -another- month, it will be ruined. It won't hold a charge. The bike will run once it gets going, and the alternator feeds current into the battery, but the battery is still dead (or sometimes it looks okay then but next morning it is dead).
Sounds to me like that's the problem!
2007-07-10 20:53:45 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Sounds like the battery has a shorted cell.You said he rode it 70 miles that says the charging system is working normal.If the chargeing system was not working he would of never made it back befor the bike went dead.Had the same problem on my honda CB750F.
2007-07-10 21:47:35 · answer #5 · answered by HyperGforce 7 · 1⤊ 1⤋
Most motorcycles have a stator and a regulator/recitifier. The stator generates an AC current which goes through the rectifier. The rectifier converts the current to DC and regulates the voltage so it doesn't over-charge the battery.
So it could either of those things, or the battery, or a combination of the three.
Here's a helpful diagram for pinpointing your charging issue:
http://www.electrosport.com/Images/fault_finding.pdf
Good luck.
2007-07-10 21:01:22 · answer #6 · answered by Sweet Baby Leroy 2 · 0⤊ 1⤋
Well, you have to investigate more. Batt. could be DOA. Asked him if he charged it. Could be that it could only take on a baby charge that was just enough to get it started. There is an off chance that the generator is going out and he is telling you a lie, but that's not likely as most old bikes have some sort of battery trama.
2007-07-11 13:41:33 · answer #7 · answered by Anonymous · 0⤊ 1⤋
Battery is shot The Alt is ok or it would not have run 70 miles
2007-07-10 20:59:34 · answer #8 · answered by havenjohnny 6 · 1⤊ 0⤋
being a honda if it wasn't charging it wouldn't rev up. so my money is on a bad battery.
2007-07-10 20:59:03 · answer #9 · answered by rasco 3 · 0⤊ 1⤋