Starter problems (possibly electric - Honda CG 125)

[alexgrandfiel...]

Hi there, I'm quite new to this so my apologies if I am being stupid! Essentially my Honda CG 125 is refusing to start with the electric ignition. The engine will turn over but won't go beyond that. Previously it would usually only start with the choke on, but now even that doesn't seem to have an effect.

Suspecting it could be an electrical problem I've just changed the spark plug and put a new battery in, but to no avail. I've got the bike relatively recently and am not too sure about it's previous service history, so replacing these things probably needed doing anyway. I also ordered some high quality oil to put into the machine which arrived today, and I'll see to later.

The reason I suspected it could be an electrical problem to start off with is because, in the weeks building up to the bike not starting, I've noticed the headlight is dim and flickers when the bike has just been turned on. And similarly, the speedo usually takes a few minutes of riding before it kicks in.

I've also checked the valve clearance - which was a little off - and that seems to have made the kick starter a lot more effective, but the electric ignition still won't do anything but turn over.

Any ideas anyone? Sorry if I seem like I have no idea what I'm doing - as I say I am new to this! Any help would be greatly appreciated. Thanks, Alex.

[bikertomm]

What do you mean by the engine will turn over? Is the starter motor just turning but engine not firing up?

Loads of people on here will be able to help in due course!

My first suggestion would be, does it bump start?

Run down the road with it with the ignition on put it in 2nd or 3rd gear hold the clutch in, run and jump on and dump the clutch with your weight over the back wheel. If it bursts into life your sorted.

If not, there's another issue!
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07' Honda Hornet now full powaah! My guide on performing an oil change!

[alexgrandfiel...]

Sorry - yes, I mean the starter motor is turning but not firing up.

It will bump start and also I can use the kick start to get it going, but ideally I'd like to have the electric starter working. Once the engine is fired up otherwise it generally seems to run fine - though I haven't had time to test if the speedo/headlight problems have subsided since replacing the battery this morning.

[Rogerborg]

OK, one thing at a time.

When you put the new battery in, did you charge it up fully first off the bike?
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[alexgrandfiel...]

I didn't bother, the instructions said it supposedly came fully charged and there was no need to do anything but fit it into the bike.

[MCN]

A most common bad starting issue is the ignition system.
The system on CG125s is pretty robust but like all electric it is dependant on good clean connections.
1st thing is to establish whether or not there is a spark at the plug.
You can test this by removing the cap on top of the spark plug, remove the plug, re-connect the plug cap to the plug, hold the other end of the plug on a bit of bare metal on the bike. Th engine block is painted so you need to find an un-painted area. The Keeping your big fizog clear of the plug hole, turn the engine over whilst looking for a spark at the end of the plug. It should be a nice clear blue colour.
If it is a watery yellow orange then you may have a problem in the ignition system. (That test can be done without removing the plug if you are fortunate to have a spare plug.)

If no spark or a poor spark you need to do the following.

Look for loose connections in the ignition system CGI Coil etc. A volt meter out of Maplins (Good one for £9) is a great toy for this and you will probably use that more than you think. Even for non-bike stuff.

Check for the spark first then take it from there.

Check the Kill Switch is fully 'on'.
If it is a bit wobbly then it may be worn out.
The kill switch is a very simply means of stopping the engine. It only grounds the low-tension ignition circuit which stops the sparks from breeding and spurting out the plug lead.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[Rogerborg]

OK, well I'd take that claim about the battery with a huge pinch of salt and get it charged up. I'd also get a voltmeter on it, with the engine off and running to see what's going on there.

You've obviously got a decent spark as as you can kick start it.

What you don't have is enough current to run the starter and the ignition circuits at the same time.

So, if the battery is fully charged (not that I believe that it is), then something is eating too much current. Most likely cause is a short which will result in excess heat somewhere in the electrical circuit, either at the solenoid or the motor itself. I believe the starter circuit is unfused on your bike (my copybike was unfused) so it can draw as much as the battery can provide.

The other thing is, have you checked your fuse(s)? You'd be amazed what you'll find in a pre-abused bike. Any chance there's a rusty nail taking the place of a fuse and masking a short somewhere?
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[Val]

[Rogerborg]

Oh, hang on, I've just noticed that you haven't said you've checked the earth connections, either the main battery earth or any -ve wiring to the ignition circuit. Worth a look.
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[alexgrandfiel...]

I realise I may have been a bit rash with the new battery! Especially now I see the exact wording on the box says 'no initial charge required' - not 'fully charged and ready to go'. Unfortunately I've got no means of charging it right away readily available. Theoretically, if I went for an extended ride this evening (using the kick start to get going) could I rely on that to charge it up?

Otherwise, the inner workings of the electrics (earth connections, loose wires in the ignition system etc) are in danger of going over my head. I've ordered a Haynes manual and once that has arrived I should hopefully be able to navigate my way through these possibilities and tick them off one by one. Until then, I wouldn't know where to start. In any case, I'll buy a voltmeter.

[Rogerborg]

Good long run can't hurt. I mean, unless your reg/rec is goosed in which case it'll cook your battery. That's why a basic multimeter is the best investment that you can make.

Loose wires are just loose wires. For example, follow your plug lead back to the ignition coil and check that the connectors there are secure - the spade connectors on my coil were prone to working loose.
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[mauzo]

[MCN]

Remove the connections at the battery.

Remove the connection on the starter motor
Remove the Earth/Ground cable.
Using a Brillo pad or some 200 wet n dry.
Clean all the surfaces of all the connections.
Clean all the surfaces where the connections attach to the bike and components.
Try starting again.
If the big conductor connectors are not celan you will not get full current from the battery to the motor.
Old bike Old dirty connectors.
Easy jobbie.

I never readed the OP correctly.

If you haven't got a volt meter yet????
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.