Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: THUNDERDOWNUNDER on November 24, 2019, 05:01:12 AM
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Ideas needed for fix . At the moment I have to charge my battery off the bike . Fully Charged it lasts about Half an hour . Starts on the button then looses power fast no starter and indicators stop . If I fully charge and leave it over night it drains . So what’s wrong Guys ?
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Most likely is corroded connectors then regulator then rectifier.
You need a decent multimeter and a methodical approch to sort out electrical problems
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Good place to start:
Place voltmeter on battery terminals and start engine. Run up to 4000 revs.
What voltage do you see?
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At 4000 rpm it’s readin 12.41. At tic over it’s 12.34 .
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How old is the battery?
Get it load tested
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That’s nowhere near enough.
When you charge it off the bike, is it the same?
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The battery is only a few months old . So don’t think it’s that . When I bought the bike a few years ago the owner said there was a short somewhere . I have put a new wiring loom on . So it’s down to the generator or regulator/ rectifier
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It does sound like the charging system is at fault, as Steve says you should be seeing a much higher voltage than you are at 4000 rpm
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With the battery loosing power over night where is the short ?
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Disconnect the 3 wires from the regulator, with ignition on check voltage at black reg wire with ignition on it should be same as battery voltage.
No more instructions till that andwer posted
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What kind of battery is it. If your battery has been deeply discharged several times it could well be knackered now. Remove it from the bike and fully charge it. Remove charger and leave it to stand for a couple of hours to settle out. Then check voltage. Leave it to stand for at least a further 24hrs and check again the battery voltage. It should be between 12.7 to 12.5 this is for lead acid and gel type. Batteries can collapse inside and take on any charge given but not store it and at the same time will cause low voltage readings at the posts when checking with the engine running. Also decent voltage readings alone do not always mean a healthy charging circuit as you can have good volts but may only be getting milliamps to the battery.
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Thanks BryanJ I will give it a go latter today if I can get a chance . I will be away for the next week so will get back to you as soon as . Rob .
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No problem, i work nights so you get answers at odd times! Easier to give you 1 test at a time even though it will take longer
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Great stuff thanks for the help !
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Back now . Tested as recommended . Wires off regulator . ignition on . test came out at 0.07 volts Battery was 13.10 volts . That was testing black wire only Black wire from multimeter to black wire from regulator and red wire from multimeter .
to positive on battery .
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Try red on meter to black at reg and black from meter to neg on battery, if this is close to battery voltage, with engine running, connect white and black at reg together and see if battery volts climb ifthe volts on black wire not close to battery you have a switch or loom promblem.
More to follow
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With ignition off battery reading was 12.77 volts .Then meter red to Black on regulator wire With ignition on I got 12.49 volts .I then joined black to white regulator wires and ran engine to 4000 revs only getting 12.39 volts not increasing!
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Right, with ignition on if you connect black to white ar reg is there a small spark showing current flow and or does alternator cover go magnetic enough to hold something like a feeler gauge?
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Connected black and white wires from regulator . Started engine and couldn’t see a spark and feeler gauge would not hold to generator cover .
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I would sugest removing sprocket cover and following the green and white wire from regulator to field, one of them is broken somewhere
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Is the sprocket cover the altinator cover ?
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Opps sprocket word gives it way .
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Just a thought the wires from regulator to field coil are brand new as the old ones where broken and fragile so I got a replacement harness from DSS . So if that’s the case maybe it’s the field coil playing up ?
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When doing the tests i forgot to say the green wire fron field coil needs to be earthed.
NEVER seen an electrically duff field or stator winding only physicaly damaged from accident or old age.
Going bed now been a loooong night
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Thanks , I will give it a go in the morning .There doesn’t seem to be any damage to The casing but it is old being 1975 .
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Thanks , I will give it a go in the morning .There doesn’t seem to be any damage to The casing but it is old being 1975 .
1975 is not old on this forum.
For the bikes. Or owners
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If 1975 is old my bikes must be off the ark and myself jurrassic!!!
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Tested again this morning .Earthed the green this time . Still the same no magnetic pick up from casing . Will have to test field cool next Any one know the best way to tackle it ? Ay even just a busted wire .
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Use a multimeter on contiuity or ohms, check between green and white if infinite start with a probe on end of one lead and use other along wire till contiuitt vanishes
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Bloody hell Bryan.
Go to bed.
It's late
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Hopefully will find the problem soon .Thanks for all your help !
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Bloody hell Bryan.
Go to bed.
It's late
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Not for him works nights ;) ;D
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Well work is a bit arbitrary, i attend a steering wheel a bit, 52 hours in 4 shifts this last week with deliveries as far apart as Plymouth and Huddersfield------NOT on the same shift!
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Way tooo Hot to work on bike today 41 degrees in the shade . Thinks it’s a strip down job coming up !
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Bloody show off! Freezing my whatsits off working on a wing
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Checked out field coil and stator all see OK . Wish it would cool down here !
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If field coil and stator are OK on resistance ground the green wire, connect the white to battery positive and with the engine running and the multimeter set to AC voltage check the readings between each of the 3 pairs of yellow wires out of stator when disconnected from loom.
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How do I use multimeter to test A/C voltage out of yellow wires ? There are two prongs from meter one positive one negative . Does one go to ground ?
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Nope there will be an ac volt setting on the mutimeter and you put one probe on each of 2 yellow wires, there are 3 "pairs" of wires, dont matter which way round as its AC not DC
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Thanks didn’t want to blow up my multimeter . All yellow wires tested 15/16 volts at 1000 rpm . It was even higher at 4000 rpm something like 24 volts . Just tested reg/rectifier . Diodes seem ok all around 500 one way only . It’s a second hand unit which came on the bike . It says 12 Volt Reg/Rec SH538-12-5.7 SHINDENGEN JAPAN . Someone has written in Pen 85 VT 250 INTEGRA . Wondering if that’s the problem ?
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Pics I forgot
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Pics
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If you are getting that AC voltage there is nothing wrong with the alternator at all. I suspect the wiring between alternator and loom ( 3yellow, 1 white, 1 green) are not connecting propery or the reg/ rec is duff and as non of the sohc fours had a combined reg/rec some po has fitted it, not necessarily correctly!!
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Yep it seems strange that all seems to be be working ok even the reg/rec is only letting current one way . I have put on a new loom DSS and a new connecting short loom from altinator to proper loom if that makes sense ? The reg/rec has no wires to the regulator that is still on the bike but the new wiring loom does have wires to it . So should I connect said wires to old regulator or not ? I will give old connectors a clean and keep my fingers crossed .
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If the field wires on the reg/rec are not connected but the old reg is you may have some miss connections somewhere.
You need to be certain that thw white wire from the old reg actually goes to the fied coil and that there is +ve 12volt on it with the ignition turned on
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With the Regulator bolted to frame what is the colour from Top to Bottom do the three wires from Loom go Thanks ?
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Just to cheer you up it was 2 degrees in the garage this morning. :)
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Green white black wires to unused regulator ? Weather here Down Under is still Hot . 2 degrees would be welcome here for half an hour !
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Just to add to the weather mix... temp in outer Sydney today will be 44 degrees and they are expecting record temps of over 50 Celcius in multiple places between Perth and Sydney...
And I am spending the afternoon outside working.. Living the Dream :)
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Mission Accomplished . Battery charging now . Thanks for all your help guys I couldn’t have done it without you . Just off for a ride in the Heat Agh!
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Mission Accomplished . Battery charging now . Thanks for all your help guys I couldn’t have done it without you . Just off for a ride in the Heat Agh!
So what cured the issue out of interest ;)
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Mission Accomplished . Battery charging now . Thanks for all your help guys I couldn’t have done it without you . Just off for a ride in the Heat Agh!
So what cured the issue out of interest ;)
Seriously - after four pages of tests, don't leave us hanging!!! ;D
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Well , after testing A/C Generator which was OK . Testing regulator/Rectifier which was fine it turned to wiring from Loom to generator . The three yellow connectors needed a good clean and the green and white wires one was broken so after cleaning and soldering . Alls well how’ve battery is charging .It was a good learning curve . So thanks again guys and a big thank you to BryanJ .
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Nice talk through Bryan. ;)
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Nice talk through Bryan. ;)
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