Little b*stard honda CBF refuses to be fixed!

[sgtcalle]

Hi all.

Been having issues with my other half's cbf125. For a simple bike the thing seems determined to be broken! Faith in Honda dented somewhat.

A few months ago had the kangaroo hopping problem which seems to affect some cbfs. Had to leave the bike sat for a while, but eventually got the fuel pump changed, only to find the battery flat. I put a new battery on it and it fired up fine. I've ridden it round a carpark (its now on a sorn) and it seems to run fine. However, now it has no headlight, tail light or dash lights. The bulbs all look good. I have read online that these lights are all powered off the alternator? The battery seems to be charging fine though, so can the alternator be fried?

Thanks in advance as always.
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CBR600F '02
Manchester

[GSTEEL32]

Sounds more to me like a faulty connector, earth or fuse.

I'd check these 3 first before faffing about with the alternator....

[Robby]

Check the fuses.

[sgtcalle]

I've read that that circuit doesn't contain any fuses. Could well be a connector or earth. anyone have a wiring diagram?
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CBR600F '02
Manchester

[GSTEEL32]

https://i574.photobucket.com/albums/ss182/hmmmnz1/Honda/cbf125COLOUR.jpg?t=1312325525

This should help. Has a couple of "sub" fuses which probably would be the start of your investigation .......

[sgtcalle]

Aye checked those little 10a fuses, they're fine. Looking at the wiring diagram I suspect the yellow wire links could be the issue as it links all the faulty lights
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CBR600F '02
Manchester

[cb1rocket]

Not uncommon for the genny to fry half its windings, similar problem with a mate and the genny was duffed. Is it def charging though?
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Honda H100S2 Rebuild - https://www.bikechatforums.com/viewtopic.php?t=253852

[sgtcalle]

I had a voltmeter across the battery and seems to be charging fine. Ruled out a faulty earth as the horn and indicators are in the same earth and they're working fine.
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CBR600F '02
Manchester

[nowhere.elysium]

Bear in mind that the lighting circuit is AC, so it'll be completely separate from everything that comes out of the rectifier. I'm not near to a wiring diagram for one yet, so i can't suggest where exactly to look, but the arrangement of the wiring circuit is a little odd.

Also, CBF 125s are bastards. My wife's one has been nothing but arseache.
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'10 SV650SF, '83 GS650GT (it lives!), Questionable DIY dash project, 3D Printer project, Lasercutter project

[Vincent]

Could you have missed a second connecter to one of the battery posts when you put the new one in?
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Space Is Deep

[cb1rocket]

What were the readings?
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Honda H100S2 Rebuild - https://www.bikechatforums.com/viewtopic.php?t=253852

[orac]

i don't know much about this bike, however from the couple of scoots that I have worked on, just because the battery is charging, doesn't mean that the alternator is fine.

There are normally two phases, on phase for the battery and the other for lights. make sure you check both phases.

as pointed out, lights are AC, horn and indicator run on DC due to the way they operate. check the battery charging does not rule out the alternator on small machines.
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Current rides - 2016 Triumph Street Triple Rx, 1994 Suzuki Bandit 400 VM, TGB 204 Classic 125cc
"with nothing left to lose, there is everything to gain. It's not the size of the dog in the fight, it's the size of the fight in the dog"

[sgtcalle]

Ok thanks for the replies. Don't think I missed a battery connector but worth a check. Battery was holding a steady 12.5v at idle, pushing 13v at mid revs. Yep, this bike has been nothing but trouble!
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CBR600F '02
Manchester

[sgtcalle]

Found some motivation to have another look at the bike.

Checked all connectors and fuses, couldn't see anything amiss. Checked the reg/rec, connectors looked fine, no sign of overheating. Couldn't check the voltage out of it as I dont have a meter here.

I whipped the alternator cover off. There is 3 or maybe 4 wires on one of the windings which are blackened. Could this be enough to cause the symptoms listed? Loath to spend £100 on a new stator if I don't have to. I hear stators can be rewound, is this correct?
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CBR600F '02
Manchester

[nowhere.elysium]

[sgtcalle]

Yes I called a few companies, they all advised it would be cheaper to replace the alternator.

Good spot on the alternator!!! Thank you, all the others I'd seen were cheapest £80 for the stator alone.

Miffed how poor this bike has been.
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CBR600F '02
Manchester

[WD Forte]

According to that diagram the stator has a single phase output to the RR
where power out is via two outputs
I'll guess rectified DC to the battery and 'something' to the lights
(AC? regulated AC? half wave rectified DC?)

If the bike runs and charges but the lights won't work
this suggests the stator is working well enough to power the DC stuff
and the light problem may be due to an internal RR failure or cabling and switch gear.
Resistance and voltage tests with a meter would help to decide this.

I found the site linked below
and if the stator is dodgy, doing a DIY rewind would be pretty easy
Sod spending circa £100 for that
https://www.bikesandtravels.com/biker.aspx?ride=730
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bikers smell of wee

[sgtcalle]

I think it's half wave ac to the lights and peripherals?

I've bought that alternator for 60 quid, most of them go for much more, so if that doesn't sort it I'll put it back on the bay and make my money back. Must admit fault finding with a multimeter isnt my strong point...
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CBR600F '02
Manchester

[sgtcalle]

Posting here for posterity, this might help someone in the future who is in the depths of google searching as I was...

My new alternator (stator) came, is now fitted, and bike now has lights! Raging man boner going on here for actually getting to the bottom of it.

Pics of the offending old stator:

https://i.imgur.com/CBfSlh1.jpg
https://i.imgur.com/LpBuPm3.jpg

Note a few burnt windings is all it takes.
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CBR600F '02
Manchester

[sgtcalle]

Double post...
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CBR600F '02
Manchester

[cb1rocket]

Very common!
____________________
Honda H100S2 Rebuild - https://www.bikechatforums.com/viewtopic.php?t=253852