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Discussion Starter · #1 ·
Hi, I have a 99 XXX model which is lovely except... it burns out the tail light filament on one of the tail light bulbs. The other bulb is fine and both bulb's brake light filaments are fine. Any ideas? Thanks.
 

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Get a volt meter on your battery, see what volts it's at when its ticking over, and reved to 4-5000 rpm, it should be any where from 14.2-14.6 volts, check your bulb connectors and fit a new bulb, if it keeps blowing it mite be your Reg/rec over charging or bad wire connections. Earth points mite need a clean. Make sure you take the negative wire off the battery before taking earth points off to clean, you dont want to cause any sparks by accident.
 

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Discussion Starter · #4 ·
Ok, thank you gents. I'll go over it with the multimeter today. Bulb holder looks as clean as a whistle. I'm in denial about the reg/rec to be honest. I had that issue with my ex 'bird', nearly made me sick.
 

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Ok, thank you gents. I'll go over it with the multimeter today. Bulb holder looks as clean as a whistle. I'm in denial about the reg/rec to be honest. I had that issue with my ex 'bird', nearly made me sick.
Has the loom fix been done ? - that can cause all sorts of electrical gremlins.

Do the charging system upgrade - one of the best mods you can do for reliability.
 

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Ok, thank you gents. I'll go over it with the multimeter today. Bulb holder looks as clean as a whistle. I'm in denial about the reg/rec to be honest. I had that issue with my ex 'bird', nearly made me sick.
Yeah just be methodical go through the system, like CBRDEANO put, check your loom factory plug for corrosion as well, it's got to be the 1 thing that can cause weird electrical problems when they go bad, keep at it you will find it in the end.
 

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Can I ask what's the charging system upgrade?
Take the charging system out of the bike loom and use a much more efficient R/R.

You wire directly from the Stator to the R/R - Then directly from the R/R to the battery.

Many people use the FH020AA R/R unit.

When it is done - the bike holds between 14 and 14.4 volts all the time - even at idle.

The std R/R does not charge at idle.
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For me ('97 carbie) I has a continuity issue in the tail loom. Never truly isolated it just cabletied up the bundle entering the tail light and that proved a fix.

Now that is just temporary. I do recommend the full multi metef and man hrs checking thru to the bigger issues if loom and RR.

Good luck.
 

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Take the charging system out of the bike loom and use a much more efficient R/R.

You wire directly from the Stator to the R/R - Then directly from the R/R to the battery.

Many people use the FH020AA R/R unit.

When it is done - the bike holds between 14 and 14.4 volts all the time - even at idle.

The std R/R does not charge at idle.
View attachment 134047
Thanks for the explanation, I was thinking the only way I could think of was to go direct to battery with the reg/rec.
I did that my my blades when I fitted a electrex world reg/rec.
 

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Discussion Starter · #11 ·
So, steady 13v at the battery and 11v at the bulb holder. I'm going to do this 'loom fix' anyway and charge system upgrade. Thanks for the quick responses.
 

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So, steady 13v at the battery and 11v at the bulb holder. I'm going to do this 'loom fix' anyway and charge system upgrade. Thanks for the quick responses.
Is that 13v with the engine running ?
And does the 13v increase at all when the bike is above 2000rpm ?

Sounds like you may have lost a phase in the stator and the battery is hardly charging.
 

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Is that 13v with the engine running ?
And does the 13v increase at all when the bike is above 2000rpm ?

Sounds like you may have lost a phase in the stator and the battery is hardly charging.
yeah sounds stuffed but with the wiring having such a catastrophic impact on the cbr's stator/rec history it just repeating itself bad wiring, bad wiring, bad wiring, first replace earth strap and remake loom wires from stator/rec to battery+ first before getting any new parts
 

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Use CBRDEANO's wiring diagram above using 10Gauge (2.59mm diameter) wire with his stated 30A fuse.

If your stator is stuffed, don't ride as you will just kill the battery, adding to your shopping list.

Also, I may have mentioned this a few times, install a small voltmeter to the dash to keep ahead of future charging problems.
 

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Cheers willjohns86,

Just to clarify, in case of any confusion......

When you test with a multimeter, you should see around 12.6v across the battery terminals, dropping to low 12's with key on, then while cranking should see above 9.5v (no charger in use + bike not ridden in prev 12hrs). When the engine fires, fast idle should give around 14v, and warm idle (eg 1200rom) 13.2 or so (which isn't charging the battery). The 5k rpm test is a bit brutal but should read under 14.5v. If higher then it's overcharging.

So the multi meter can do a battery test and a charging system health check in one go. But the bike needs to be resting off charger for 12hrs to get true readings.

As for blowing the same bulb all the time, make sure that circuit is good.....no cracked solder joints or rubbing wires, vibration or any items like tools etc in the tail piece hitting the connector (and check the ecu box is strapped down & not allowed to bounce around while riding).

The new R/R's are great as has been said, like cars, the battery is being charged at idle with 14v, but if there is no problem indicated by the above test, then you don't have to spend unless you want to.

My dear old BB still pulls the correct numbers so I haven't upgraded......but it's not my primary ride so there's no pressure......and I haven't seen a bulb blow for a long time ;).

(y)
 

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Just another thought.
Are you buying bike specific bulbs or just using standard car ones ?

The bike specific bulbs are thicker elements to put up with the harsher ride compared to a car.
 

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Discussion Starter · #17 ·
Right. Sorry for taking so long to reply, been mad busy with work. The multi meter showed steady 13v at the battery at 5k rpm and steady 11v at the bulb holder at the same revs. The charge at the battery was 11.5 at idle and still constant 11 at the bulb at idle. The bike has not been kept on a charger. I've had the bike around a month now and it doesn't appear to have any charging issues in as much as it will run perfectly for a day or two while I have the chance to use it then sit, without a charger, and 4 days later, start on the button and be perfect again. I'll check it again with a better multimeter and get a bike specific bulb before I go any further. Thanks again. I'll be back with more results. Some great knowledge on here!
 
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