Honda-SOHC
SOHC.co.uk Forums => CB750 => Topic started by: PHILIP2908 on April 18, 2017, 10:08:44 PM
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Well I tried to get the previously running K2 going again, but no joy.
When the starter button is pressed, I still only get 10.5 volts at the solenoid which is not enough to trigger it - just can't figure it out. I'm fairly handy with electrics (or so I thought). The (new) solenoid clicks when connected to the fully charged (new) 12v battery. And there is continuity across red/black wires when the (new) ignition switch is moved to position 1. Why is it that there is only 10.5v in the black wire circuit? That's ok for lights, horn and indicators but not enough for the solenoid.
Its been sat on the centre-stand since Sept and hasn't moved, and it will sit there until I (or someone else) can figure it out.
I got so cheesed off I got the Mercedes out which started on the button after 6 months in the garage (I only tax it for 6 months - I refuse to pay £250 or so for a full year). MoT next week and off into the sunshine - the K2 can stay where it is.
Any ideas anybody; rectifier, safe start device, something else.....
Thanks in advance.
Phil
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Check the volts at the battery terminals as 10.5 is a bit low. If theres 12V at the battery then you've lost 1.5 volts somewhere - usually a bad connection.
Also check the negative side. A bad earth will cause similar faults.
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Try putting jump leads from the car battery to the bike battery, even new batteries can get a duff cell, which would explain the voltage drop under load. If it works, your "new" battery is duff, if it doesn't, check and double check the earth, especially if the frame has been painted or powder coated, or try a jump lead from the battery negative to a clean engine bolt (no paint on it!) and try it again. What happens if you bridge the 2 terminals on the solenoid with a large screwdriver?
Sent from my X6pro using Tapatalk
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Double check that the solenoid has a good earth contact to the frame as stated, also clean starter motor contact with solenoid. I know it's a nightmare, but keep at it and hopefully you will find the source of the problem.
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Good advice above regarding the earth circuit, it catches out alot of diagnosis as you are generally looking at investigating the supply side.
Something else to do, you can fix a lead to battery positive and use that to fire the solenoid directly to its tab and so bypass the rest of the bike's start circuit kit. If it works then you know you are looking at the trail from battery down to the solenoid and not the rest.
That voltage of 10.5 maybe coincidentally close to a duff cell in the battery but that is about what you get with a cell out, so you need to verify if it's OK.