My honda CBR has ruined 3 batteries in the past three years. Does anybody know what's wrong with it?

Question

I have bought 3 batteries in the past 3 years since my bike keeps ruining them. I don’t know if it's the regulator, alternator or just an electrical problem. I need to know how to determine the problem without having to take it to the shop. Please help!!!

Answer 1

With the bike running, put a voltmeter across the battery terminals to check the alternator voltage. 13-14 volts is the norm. If you get a much higher reading, like 16 or 17, your alternator is overcharging. The most common cause for early battery failure on motorcycles is neglect. Has the water level been kept full? If you let the cells run dry, that will cook the battery. Also if you let the bike sit for long periods and the battery gets low, it causes sulfation of the lead plates inside. Use a Battery Tender or other smart charger during storage to prevent this. Without a battery tender, my bikes batteries usually lasted 1-2 years. With the battery tender, they started lasting 4-5 years. At that rate, the charger paid for itself pretty quickly, and my bike was always ready to ride, even if it was cold outside and the bike hadn't been started in months.

Answer 2

I can see three possibilities for your battery failure.

(1) The alternator's stator may have shorted out and isn't charging the battery up.

(2) The regulator or regulator-rectifier is malfunctioning and is overcharging the battery. While not good for the battery, the main problem from overcharging is that it boils the water out of the battery. Too little electrolyte (liquid in the battery) equals dry plates and if left dry, they fail.

(3) You let the thing set all winter without periodically charging the battery. Engine managment computers, digital clocks, etc all continually use small amounts of electricity even when the bike isn't being run. Over a long period of time, the battery runs down, the plates sulfate and the battery is shot. This is the main culprit when it comes to needing a new battery every spring.

To try to determine your problem, first check to see if the battery has liquid up to the proper level. If it extremely low, say 25% left, that could be number 2. If it's right up to par, it could be #1 or #3. Then do as the one fellow said. Start the bike at night and with the headlight shining on a wall or something, at approximately 2000-2500 rpm you should see the headlight suddenly brighten up. Rev it up to 6 grand or so and the brightness should remain constant. If it doesn't brighten at all, it's likely the stator. If it continues to get brighter and brighter in direct relationship to the increase in engine speed, it's probably voltage regulator. If this is the case, you may have also experienced other bulbs being burned out.

If the headlight test checks out ok, the battery electrolyte level stays more or less constant after several hundred miles of riding and you let it set all winter without charging the battery, then cause #3 is probably it. If you do let it set for months at a time and it has a clock or other continual draw components, charge the battery once a month or at least disconnect the battery cable.

Answer 3

It is probably the regulator/rectifier. It gets too hot and shorts itself out. I have had it happen on my VFR twice. First test is to start your bike and when you rev the bike up you should see the lights get brighter. I put my hand in front of the headlights to check it. If they get brighter then your stator is working fine. For any detailed tests you need to buy a multimeter. Get one at Wal-mart or any electronics/autoparts store. Should be around 10 dollars. Hook your meter to your battery and rev the bike again (3-5000 rpms). The volt meter should read 13.5-14.5 volts. If the reading is low then you will need to test the regulator/rectifier. Exact tests are in the Clymer manual, but are simple and can be done with your multimeter. All testing can be done in about an hour or two even if you don't know exactly what you are doing (much less if you do). If it is bad be sure to get a replacement on the internet ($120). Also look on the internet for ways to keep it cool the next time you install it. (heat sink, computer cooling fans, etc.) Good luck.

Answer 4

Anytime your battery goes - even if it's a 'timely' death - you should inspect the charging system.

I could spend all day typing how to diagnose the charging system, but if you buy a factory service manual, the procedure's in there... along with plenty of other great info. Armed with it and a good multimeter, you should be able to figure out your problem.

Some Honda CBRs are known for regulator/rectifier problems, but don't assume anything. Test each component out, in turn, including the wiring. And if you do find a problem - keep testing - because often one bad component in your charging system will bring down another.

good luck!

Answer 5

One last thing that nobody mentioned. It is possible for it to freeze and crack the plastic. Where do you live? Do you store your bike outside? Those can be factors if you live somewhere cold enough to do that. All the other answers are great and more likely to fix the problem but this is something to consider.

Answer 6

if a voltage regulator is screwin up, that can let a battery overcharge. typically, bikes have a very small charging system. a voltage regulator isnt hard to replace, but it isnt very cheap either. a regulator for my bike will set ya back almost 100 bucks.

Answer 7

theres a possible chance that the battery acid is leaking out of the cbr, that could be from drop the bike or from past accidents. thats what my cbr was doing but i soon fixed it, it wouldn't start up cause the fluid wouldn't go to the gadge

Answer 8

Get a Clymer manual for your motorcycle (see Ebay) and a digital multimeter.
The Clymer manual will tell you how to check your regulator, rectifier, and stator without taking your bike engine apart.

Answer 9

IS the battery draining do you have to charge it regularly do you store it for long periods of time need to know if you want a informed answer, but your first step is to get a tester and see how many volts the stater is charging at

Answer 10

I suggest you take your bike to an auto parts store and have them do a diagnosis on all your electrical parts, many parts stores do this free. I always buy a repair manual for whatever vehicle I own as well.