Author Topic: Electric start issues  (Read 239 times)

Offline Coppertop1234

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Electric start issues
« on: July 23, 2026, 01:04:39 PM »
Hi all bit stuck with diagnoses of slight problem.
Bike on trickle all time in garage.
Starts on the button no issues
Go for a run 20 40 miles perfect ride.
Go to use button to stat and starter tries once and stops

It's like a flat battery symptom

Bike kick starts first kick ride home same issue.
Mega shows Bike is charging
New battery
Earth's all cleaned
New wiring loom
Changed stator just in case
New switch gears

Last thing I can think is regulator rectifier

Open to views if anyone has had similar?
Cheers

Keith
« Last Edit: July 23, 2026, 01:53:09 PM by Coppertop1234 »
I Love Tinkering with Old Classics
1970 Mobylette 50cc  
1972 Honda Cb175
1974 Yamaha Rd250  
1962 Triumph 650 Bonneville
1972 Norton Commando
1978 Honda CB400/4
1976 CB750F1 
1976 Suzuki GT750 Kettle
1978 Honda CB 750 F1 
Married Life No Bikes for a while then
1975 CB Honda 400/4 Restoration
1976 Kawasaki Z650   Restoration
2002 Suzuki GSX1400
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1978 Honda cb750 F1 Restoration
1977 CB 250 Dream    Restoration
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Offline exvalvesetdabbler

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Re: Electric start issues
« Reply #1 on: July 23, 2026, 02:41:24 PM »
Bit of a,long shot, if you're on oem regulator, check the wire wound resistor on the back of the regulator.

I had a battery go off last season and checked all the obvious bits that you have. Cleaned the regulator contacts and left a fragment of  of paper towel between the normally closed contacts, wasn't charging at low revs and a spanner wouldn't  stick to the alternator cover with ignition on.
It was fine on open roads but  draining the battery pottering around town.
Since fitted a voltmeter.  You need 3-4000 revs to get any meaningfull charging. Once you're up to speed or over 6000 rpm it should be up to 15v and not go over.

If you are running aftermarket ignition coils with a lower resistance and headlight on it might struggle a bit unless you ride it like you stole it.

Regards
Dave



Offline Bryanj

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Re: Electric start issues
« Reply #2 on: July 23, 2026, 07:32:42 PM »
Regulator and Rectifier are seperate parts unless the bike has been fitted with an aftermarket unit

Offline Coppertop1234

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Re: Electric start issues
« Reply #3 on: July 23, 2026, 07:44:27 PM »
All standard fit at moment but I am down to these as my last options.
Aftermarket do a multi 2 in 1 version to do both jobs
They are.not too dear but didn't want to change if I was missing something simple someone else had already diagnosed.
« Last Edit: July 23, 2026, 08:14:01 PM by Coppertop1234 »
I Love Tinkering with Old Classics
1970 Mobylette 50cc  
1972 Honda Cb175
1974 Yamaha Rd250  
1962 Triumph 650 Bonneville
1972 Norton Commando
1978 Honda CB400/4
1976 CB750F1 
1976 Suzuki GT750 Kettle
1978 Honda CB 750 F1 
Married Life No Bikes for a while then
1975 CB Honda 400/4 Restoration
1976 Kawasaki Z650   Restoration
2002 Suzuki GSX1400
1976 Honda cb750F1  Restoration
1978 Honda cb750 F1 Restoration
1977 CB 250 Dream    Restoration
1977 CB400/4  - The last one - Restoration

Offline Oddjob

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Re: Electric start issues
« Reply #4 on: July 23, 2026, 10:05:59 PM »
Have you checked the contacts inside of the generators multi connector, they are known to corrode badly and the vibration as the engines running could mean they lose contact and don’t allow the battery to charge.
Kids in a the back seat cause accidents.
Accidents in the back seat cause kids.

Offline Coppertop1234

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Re: Electric start issues
« Reply #5 on: July 24, 2026, 08:23:39 PM »
checked connectors all seem fine
Battery on trickle all week reading 13.48
tried electric start twice getting fuel through
no 3rd attempt flat

Kickstart first attempt (all be it me standing on 2 bricks so i could kick it up)
mega reading 14.28 14.5 at battery while revving bike

so battery holding charge ok and bike charging ok
a lot of drain for just 2 attempts with electric start.

think i will try taking starter out and cleaning it up or if i have a spare replace it just to rule it out.

puzzler??
I Love Tinkering with Old Classics
1970 Mobylette 50cc  
1972 Honda Cb175
1974 Yamaha Rd250  
1962 Triumph 650 Bonneville
1972 Norton Commando
1978 Honda CB400/4
1976 CB750F1 
1976 Suzuki GT750 Kettle
1978 Honda CB 750 F1 
Married Life No Bikes for a while then
1975 CB Honda 400/4 Restoration
1976 Kawasaki Z650   Restoration
2002 Suzuki GSX1400
1976 Honda cb750F1  Restoration
1978 Honda cb750 F1 Restoration
1977 CB 250 Dream    Restoration
1977 CB400/4  - The last one - Restoration

Offline McCabe-Thiele (Ted)

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Re: Electric start issues
« Reply #6 on: July 24, 2026, 08:35:03 PM »
Trying to think outside the box, following are my thoughts

1. Is the solenoid faulty?
 If you bridge the contacts when the battery is apparently flat does it crank over.

2. A new battery, is it definitely the right specification?
C.C.A. and Ah rating, voltage alone does not tell the whole story, new batteries can be mis-labelled apparently.
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Offline Skoti

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Re: Electric start issues
« Reply #7 on: July 24, 2026, 08:42:43 PM »
Load test the battery because it seems like a faulty cell breaking down under load.
Or try another battery first if you've not got a tester.

Good luck
Skoti


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Offline Coppertop1234

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Re: Electric start issues
« Reply #8 on: July 24, 2026, 08:58:29 PM »
like the thoughts guys

will check them out tomorrow

Ta

Keith
I Love Tinkering with Old Classics
1970 Mobylette 50cc  
1972 Honda Cb175
1974 Yamaha Rd250  
1962 Triumph 650 Bonneville
1972 Norton Commando
1978 Honda CB400/4
1976 CB750F1 
1976 Suzuki GT750 Kettle
1978 Honda CB 750 F1 
Married Life No Bikes for a while then
1975 CB Honda 400/4 Restoration
1976 Kawasaki Z650   Restoration
2002 Suzuki GSX1400
1976 Honda cb750F1  Restoration
1978 Honda cb750 F1 Restoration
1977 CB 250 Dream    Restoration
1977 CB400/4  - The last one - Restoration

Online Mikep328

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Re: Electric start issues
« Reply #9 on: July 25, 2026, 06:02:21 AM »
Main cable from battery to relay/starter OK/connections good? 
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Offline TrickyMicky

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Re: Electric start issues
« Reply #10 on: July 25, 2026, 07:38:20 AM »
Definitely sounds like a duff battery, irrespective of its age. It may have been a bit older, but I have just had the same problem with my 250. (No kickstart!!!).  Left it on charge overnight,  was reading 13.8 volts,  touched the starter button in the morning to check. Magic!!.  Went indoors to put all the riding clobber on, pushed bike out of garage, pressed starter button and all it did was kill the neutral light. New gel battery fitted, sanity returned.

Offline Coppertop1234

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Re: Electric start issues
« Reply #11 on: July 25, 2026, 09:45:52 AM »
All sorted it was the brushes in the starter motor.
Replaced with a spare and starts so much quicker ,motor hardly spins and she's away.
Thank you for comments during diagnoses process.
Cheers

Keith
I Love Tinkering with Old Classics
1970 Mobylette 50cc  
1972 Honda Cb175
1974 Yamaha Rd250  
1962 Triumph 650 Bonneville
1972 Norton Commando
1978 Honda CB400/4
1976 CB750F1 
1976 Suzuki GT750 Kettle
1978 Honda CB 750 F1 
Married Life No Bikes for a while then
1975 CB Honda 400/4 Restoration
1976 Kawasaki Z650   Restoration
2002 Suzuki GSX1400
1976 Honda cb750F1  Restoration
1978 Honda cb750 F1 Restoration
1977 CB 250 Dream    Restoration
1977 CB400/4  - The last one - Restoration

Offline Johnwebley

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Re: Electric start issues
« Reply #12 on: July 25, 2026, 10:55:51 AM »
Interesting

I had similar issues with the dyno/starter on my Yamaha CS5

turned out to be carbon dust between the segments on the cummutator ring,

Narrow screwdriver cleaned the gaps,

Now working properly


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