Author Topic: Won't start  (Read 237 times)

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Phil C

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Won't start
« on: 03 January, 2019, 14:11:49 »
Hello all, My B40, which normally starts second kick, doesn't want to play today. I haven't started it for a couple of weeks, so thought I'd better fire it up, but it wouldn't start. Symptoms are:
 - fired once or twice but didn't start
- loud crack on one occasion, as I kicked it over, somewhere near air filter/battery, followed by fumes for a few seconds (backfire or something electrical?)
- spark at plug
- no headlight
- horn works

Any suggestions please?  Phil.

Throttle cable bits have also fallen to pieces a bit, but I'll come to that. Never rains but pours! (actually, down here in Devon, it rains a lot)

Phil C

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Re: Won't start
« Reply #1 on: 03 January, 2019, 14:40:41 »
By the way, forgot to mention, fuel floods from the carb when I tickle it.

Plug a bit black and oily, but I guess that's from flooding when trying to start it.

Phil C

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Re: Won't start
« Reply #2 on: 03 January, 2019, 15:30:38 »
It seems an awful coincidence that the lights won't work. But there's a spark at the plug, so the starting problem cant be electrical, can it?

Of course it's the first bit of cold weather we've had. Could that be it? It's not that cold, surely.

It's frustrating, but interesting.  Would be more interesting if I hadn't done my knee in kicking it over.

Anyway, any thoughts would be much appreciated.

Phil.

AdrianS

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Re: Won't start
« Reply #3 on: 03 January, 2019, 16:43:20 »
Could be a number of things.
My B40 will overflow from the carb when tickling it for more than a few seconds. At least you have got fuel.
The lack of lights may be a coincidence but double check you have a good regular spark at the plug after you have cleaned it!
My initial thoughts are that you have flooded it. Do you use a the choke? I find that when the weather is very cold, I have to use the choke to start mine, normal weather needs no choke.
I suggest you check for a spark first, leave the plug out for a while to let the cylinder dry out a bit and then try restarting it with just a small amount of ticking and open the throttle a bit when kicking it over. Should start then.

ps. check your battery voltage; cold weather does kill them! May be the cause for a lack of lights.

Phil C

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Re: Won't start
« Reply #4 on: 03 January, 2019, 17:17:34 »
Thanks Adrian. Okay I've just checked the voltage across the battery terminals:  5.95.  I think that's pretty low? -but would it be too low for the lights to work?  And even though I'm getting a decent spark every kick? 

I normally use a bit of choke, a bit of throttle, and she bursts into life, usually second kick.  But not today.  I wonder if my problem with the throttle cable mechanism might be a factor. I'll need to have a look at that, but first I'll try kicking it over again tomorrow.   

Phil.

Phil C

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Re: Won't start
« Reply #5 on: 04 January, 2019, 10:32:49 »
Tried it this morning. A bit of choke, a bit of throttle, a tickle (fuel floods out), all as usual, but it didn't fire. Getting a spark sometimes but not always (why is that?) Plug quite dark but not sooty or oily - good enough, I'd have thought. It's a cold morning. Any explanation/advice please?   Phil.

DerekAnderson8

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Re: Won't start
« Reply #6 on: 04 January, 2019, 11:49:18 »
have you charged the battery?

or connect charger and try it that way i just started my A65 with a flat battery.

good luck


Phil C

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Re: Won't start
« Reply #7 on: 04 January, 2019, 13:13:23 »
No, the only charger I have is 12v.  the battery was showing 5.95v yesterday. Should that be enough to start it?  And should it be enough to power the lights?   Phil.

ANDY HIGHAM

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Re: Won't start
« Reply #8 on: 04 January, 2019, 13:48:03 »
A spark outside the combustion chamber is no guarantee that it will spark inside with fuel and compression.
The battery voltage should be around 7 volts. Measure it with the ignition on and points closed it should still be over 6.5V

JulianS

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Re: Won't start
« Reply #9 on: 04 January, 2019, 14:07:54 »
If you think the battery is lowhave you tried starting with ignition switch in the emergency start position?

If the headlight does not work and providing the bulb is OK you need to check all your electrical connections including earth.

AdrianS

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Re: Won't start
« Reply #10 on: 04 January, 2019, 16:05:35 »
My battery reads about 6.5 volts fully charged. It was the same when new. I would try and get yours charged and see if it holds its voltage after being charged. Cold weather will let you know if the battery is on its last legs!

You have obviously got fuel. Is the plug wet after trying to start the bike?. If so, fuel is getting into the engine.

It seems the problem may be with the ignition. Check all low tension and high tension connections. You can check if there is a feed to the coil with a meter or a light bulb. If you have a good spark at the plug when kicking over the bike should fire. A coil that is breaking down may stop the bike from running properly as would a faulty condenser but the bike should still fire.
I think the first step is to check the ignition circuits and get a fully charged battery.

Phil C

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Re: Won't start
« Reply #11 on: 04 January, 2019, 17:48:11 »
Thanks everyone.

There is no emergency start position, but thanks for the suggestion anyway.

Regarding the lights not working, I guess that can't be due to a low battery, because the horn and the stop light work.

Regarding the bike not starting, I have more questions:

1. Any suggestions for a charger, as I guess I need to buy one?  There doesn't seem to a lot of choice for 6v.  Accumate maybe?

2. How do I check the ignition circuits? (I have a multimeter)

Thanks for your help so far everyone - very much appreciated. 

Phil.


AdrianS

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Re: Won't start
« Reply #12 on: 05 January, 2019, 13:54:30 »
My charger is a switchable 6v/12v charger from an auto accessory shop. I'm sure Halfords would have one.

With regard to checking the ignition, check that there is a voltage going to the coil - should be battery voltage, when the ignition is switched on. For a positive earthed bike, the measurement between the coil -ve and the bike frame ( earth) should be battery voltage.
Check also that the coil +ve is actually going to earth by setting the multimeter to an Ohms setting and putting the leads from the +ve on the coil to earth ( the bike frame). If the meter doesn't read zero, first check the points are not open!

To check the coil you need to know the resistance of the circuitary inside it. I wouldn't worry at the moment about this.
Check physically all connections to the coil and from the ignition switch and back to the battery. Check the HT lead coming out of the centre of the coil to make sure it is seated properly and the same with the plug cap. I would fit a new or replacement spark plug to the HT lead and touch the engine cylinder head and kick it over with the ignition on and check for a good spark.

Hopefully with a charged battery and a new plug you get a good spark!
I also assume you have checked the obvious - the battery connections are good, clean and tight!