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I finally got my voltmeter working again today and wanted to test another thing that I had repaired. I had worn my 10 yr old battery down flipping the bike on while not starting it during trouble shooting and it was at about 77% charge per my smart charger. I didn't wait for it to charge fully but took a ride and while on the highway at 83 mph my voltage slowly dropped to 11.8 volts. When I slowed down to 50 the volts went back up to 12.8. Nearing my friends house and going 30 it went up to 13.5.
On the way home I was doing 85 and it went down to 11.8 again. Thought it might have something with the cruise control so I shut it off. That made no difference. Slowed to 70 mph and voltage went up to 12.4. Slowed to 60 and volts went up to 13.3. Went 50 in a gear where revs were 4000 like at 80 but volts didn't really lower. Got home and sitting in the drive way I revved the engine to 4000 a couple of times and volts went to 14.2.
Turned it off and put the smart charger on it to see the percentage to see if the battery was charged up by my charging system. In 65 miles it had gone from 77% to 90%. I am not running any auxiliary lights or aftermarket bulbs. I have a power source that was switched off and the cruise made no difference whether it was on or off.
I do plan on getting a new battery too.
Normal? Thought volts should go up the higher the revs.

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BUT. i recently had an odd experience similar in some way to this. I found voltage was dropping off at high revs. I ended up connecting the output of the RR directly to the battery because i figured that something in the loom was causing the problem. Hasn't glitched since. You might want to consider that ... it's easy to do and cheaper than a new battery.
 

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Agree, sounds fishy. First off I would check the voltmeter itself. I just changed my 2 year old cheap ebay voltmeter for a new one ($8 delivered) because it was showing symptoms as above. All good now.
 

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Agree, sounds fishy. First off I would check the voltmeter itself. I just changed my 2 year old cheap ebay voltmeter for a new one ($8 delivered) because it was showing symptoms as above. All good now.
It is a cheap Ebay voltmeter. I also have it connected to keyed power going to the fan relay. It is mounted on the left black fill panel just to the left of the tank. I also found out that when in town going slowly or sitting at a light it heats up and quits working. As soon as I take off from the light and air flows by to cool it, it starts working again.

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Discussion Starter #7
BUT. i recently had an odd experience similar in some way to this. I found voltage was dropping off at high revs. I ended up connecting the output of the RR directly to the battery because i figured that something in the loom was causing the problem. Hasn't glitched since. You might want to consider that ... it's easy to do and cheaper than a new battery.
Easy? How so? I am not real good with that. Someone points me in the right direction and I can go do it. Just snipped and soldered in 4 wires as I put in new divider on the cruise control. But Beestoy pointed me in the right direction!

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Discussion Starter #8
Do you trust your voltmeter to the tenth of a volt?

What regulator are you running?
Stock, 2001

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I had a simaler problem the auto reset circuit breaker on the positive lead from the RR to the battery had slightly lose nuts causing high resistance and heat slow down it cools off and then closes and charges again.
 

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It is a cheap Ebay voltmeter. I also have it connected to keyed power going to the fan relay. It is mounted on the left black fill panel just to the left of the tank. I also found out that when in town going slowly or sitting at a light it heats up and quits working. As soon as I take off from the light and air flows by to cool it, it starts working again.
You have a known problem with a measuring device. You have no symptoms of a problem with your bike other than the questionable information from the measuring device. Don't look for trouble.

If the voltmeter stops working as it heats up, resistance is increasing through its circuitry and will give erroneous readings. Worse case, clamp your VOM on the battery and go for a ride. That should give you a better picture of the situation.
 

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You have a known problem with a measuring device. You have no symptoms of a problem with your bike other than the questionable information from the measuring device. Don't look for trouble.

If the voltmeter stops working as it heats up, resistance is increasing through its circuitry and will give erroneous readings. Worse case, clamp your VOM on the battery and go for a ride. That should give you a better picture of the situation.
The best solution. Find a quality multimeter, mount it on handlebar with plastic rubber, clamp its poles directly to the battery and drive the bike and check the voltage. I had the same situation with my blakbird and varadero. İn blackbird it was the nearly burned RR connection, and in varadero it was a malfunction, cheap ebay voltmeter. RR problems are famous in early carb birds.
 

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I'd do what bull suggested. Always best to take a second reading with a reliable DVM. Then go from there. I'm suspecting the Ebay meter is bad.
 

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I'd do what bull suggested. Always best to take a second reading with a reliable DVM. Then go from there. I'm suspecting the Ebay meter is bad.
So do I after it heated up and quit working then cooled down and started workingagain. Do you have a link to the one you put in the upper left part of your dash? I loved how that looked sitting there.

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It's been so long since I picked those up. I'll have to see what I can find. I bought 3 of them originally for each of our BB here. I can't find the other 2 right now I'll do some searching when I get back and see what i can find out. I bought them off of Ebay. They were a 3 wire DC miniature meter in green.
 

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Check the voltage at about 4k rpm with headlights on full. Odd voltage behaviour, if it's not an issue with the meter, would suggest an issue with the regulator/rectifier. You also need to test the stator.
 

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:hmm:........ where did I read the post about old batteries not accepting a full charge after a few years and eventually cooking the RR/alternator coils....... I think it was posted way back in 2006.......

Are you sure your 10yo battery isn't the problem? I have never got more than 4 years out of any battery with regular use (I also have never had to replace a RR, but my alternator coil did fail at 73,000kms and I had it rewound with heavier wire).

Have a look on the technical thread...... it was a very informative article....... if you run a standard AGM battery then it's got to be knackered now..... probably only accepting 30% of it's capacity. The RR will be working overtime to dump excess volts out as heat.

If you have an Odessey or similar super battery, then maybe it is still ok........ do you have access to a battery load tester to check your old battery?

Might be cheaper to just slip a new AGM in before you burn up a Reg Rect or alternator (which might also be failing due to the ancient battery or oil contamination etc etc).

PS The only way for you to test your battery is to put your voltmeter across the terminals and test the 'cold cranking volts' on 1st start (after battery left off a charger for 12hrs minimum). If the meter reads under 9.5v while cranking the motor....... that battery is toast.

It's no good just testing the standing volts as batteries are tricksters..... but a fresh battery will have above 13v standing...... and your charging system should be pumping 14.5v in on fast idle. I've had mates tell me "oh the battery is ok, it reads 12.4vs but the bike won't start"...... when i turn up with an old battery that is still ok, the bike jumps into life........ trickery eh?
 

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Discussion Starter #18
Ok, new LiFePO scorpion stinger battery ordered. After running for long enough to charge the battery the suspect meter is saying that the battery voltage is 11.8 prior to start and goes down to 7.4 when cranking. Battery was 10 yrs old so I got a new one and plan on finding a better quality meter and putting it somewhere on the dash. This one is blue and I cannot see it during bright sun. If anyone has a source for a compact voltmeter please post it up!!

Guy

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My battery just showed up on the front porch! Will put it in tonight... if nothing else comes up.

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I just replaced Stator to RR with connections after the team here schooled me through the troubleshooting. Melted connections and burned up Stator. With my voltmeter on the dash it's now hanging at 13.7 majority of the time. After losing some faith its once again feeling bulletproof! hope its just your batt!
 
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