Resend my activation email : Register : Log in 
BCF: Bike Chat Forums


Please help! No spark on cg125, I'm so stuck!!

Reply to topic
Bike Chat Forums Index -> The Workshop Goto page 1, 2  Next
View previous topic : View next topic  
Author Message

bevlak
Two Stroke Sniffer



Joined: 18 Jun 2018
Karma :

PostPosted: 20:14 - 13 Sep 2018    Post subject: Please help! No spark on cg125, I'm so stuck!! Reply with quote

Hi all,

My second post here so thanks in advance for any help you can give!

Ok I've got a '94 cg125 I'm turning into a brat/tracker type thing

The bike was running fine and nearly ready for MOT, then one morning it won't start. Totally out of nowhere! No spark at all.

Bike spec:

Kickstart
Points ignition
12v

Things I've tried to no avail:

Checked earth to frame (it's fine and horn, flashers etc all work)
New fuse
Charged battery
Replaced ignition coil
Replaced generator/stator
Shouting
Swearing
Crying (don't tell my mates about that part)

Between each thing I've tried above, I've put the spark plug to the engine case and kicked it over. Nothing at all, no spark, no shock to my Fingers. This thing used to shock strong enough to make you drop the spark plug!

I'm totally out of ideas here guys, I'm sure there's some stupid thing I'm not checking or haven't plugged in?! Any help would be hugely appreciated, I'm so frustrated at the moment, and really don't want to shell out hundreds for electric work at the garage. I've done everything myself so far so would be a real blow to have to take it somewhere (blow to my pride that is)

Is there some other earth point I'm missing here? Is there one in the engine anywhere that might be bad? Can't find anything in Haynes about it.. help!

Again any ideas welcome!

Thanks!

Sam
____________________
Cg125 br-k '94
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

Nobby the Bastard
World Chat Champion



Joined: 16 Aug 2013
Karma :

PostPosted: 22:48 - 13 Sep 2018    Post subject: Reply with quote

Have you tried putting fuel in it?
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint 1050 ST
 Back to top
View user's profile Send private message You must be logged in to rate posts

jaffa90
World Chat Champion



Joined: 06 Apr 2016
Karma :

PostPosted: 00:35 - 14 Sep 2018    Post subject: Reply with quote

Have you tried bypassing or ruling out the the spark plug, cap and h.t. lead?
 Back to top
View user's profile Send private message You must be logged in to rate posts

WD Forte
World Chat Champion



Joined: 17 Jun 2010
Karma :

PostPosted: 02:20 - 14 Sep 2018    Post subject: Reply with quote

So the 'swap and hope' method isnt working out for ya ?
OK, why not try Try 'test not guess' instead?

As its points type motor
I'd have used a meter to check for power on the Black/White wire
from the ignition switch which is connected to both the coil and points
No power here, no spark.

Buy a meter
____________________
1979 CX500 - Zanussi Wd12: - LG Combi Multiwave - Swan 4 slice toaster with removable crumb tray
 Back to top
View user's profile Send private message You must be logged in to rate posts

Fourte
Spanner Monkey



Joined: 17 Aug 2018
Karma :

PostPosted: 08:02 - 14 Sep 2018    Post subject: Reply with quote

Buy a cheapo meter as above - it will save hassle with household electricals too.

You mention the earth - have you checked where ALL of the earth contact parts are? Don't just check the battery earth - it's likely the coil will have its own point of contact to earth.
 Back to top
View user's profile Send private message You must be logged in to rate posts

bevlak
Two Stroke Sniffer



Joined: 18 Jun 2018
Karma :

PostPosted: 08:17 - 14 Sep 2018    Post subject: Reply with quote

Thanks @WD Forte this is the kind of thing I need!! I'm a total idiot when it comes to electrical stuff. I think I fundamentally don't understand it, so I try and avoid it wherever I can. I do have a multimeter though.

So I'm checking for voltage on the black/white wire here? Am I putting the probes on the earth and the black/white and kicking it over? If I find where it stops getting power then what?

@jaffa90 - used multiple (new) spark plugs, and the ignition coil came with brand new HT lead so doubt this is the problem. Haven't tested the cap though, didnt think of that!! would you know what settings on the multimeter I should be testing here?

@nobby - not sure if you meant to reply to this thread or someone else's? The problem here is spark, not fuel, although yes, there is a full tank of good fuel in it!

Thanks everyone for your help here, will have a look this weekend and get back to you!
____________________
Cg125 br-k '94
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

bevlak
Two Stroke Sniffer



Joined: 18 Jun 2018
Karma :

PostPosted: 08:20 - 14 Sep 2018    Post subject: Reply with quote

Fourte wrote:
Buy a cheapo meter as above - it will save hassle with household electricals too.

You mention the earth - have you checked where ALL of the earth contact parts are? Don't just check the battery earth - it's likely the coil will have its own point of contact to earth.


As far as I can see from the wiring diagram and visual inspection the coil earth's through its bolts into the frame. There's no wire connected to earth, just a black/white wire to the generator and a ht lead to the plug. Do you know own what I'd set the multimeter to to check earth on the coil?

Thanks for helping fourte!!
____________________
Cg125 br-k '94
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

jaffa90
World Chat Champion



Joined: 06 Apr 2016
Karma :

PostPosted: 10:51 - 14 Sep 2018    Post subject: Reply with quote

Earth check,meter set on 200 OHMS (usually at 6 0,clock) one lead on coil earth and the other on the battery /frame earth, (the reading should move from 1.
Coil feed check, meter set on 20v dc (usually 10 o,clock) Red lead into the coil input wire (NOT HT LEAD) and black lead on frame / battery earth, ignition on and kick over the engine, you should get a quick voltage reading.

Meter sockets, red lead into V/ohms/mA, black lead into COM.
 Back to top
View user's profile Send private message You must be logged in to rate posts

bevlak
Two Stroke Sniffer



Joined: 18 Jun 2018
Karma :

PostPosted: 11:13 - 14 Sep 2018    Post subject: Reply with quote

jaffa90 wrote:
Earth check,meter set on 200 OHMS (usually at 6 0,clock) one lead on coil earth and the other on the battery /frame earth, (the reading should move from 1.
Coil feed check, meter set on 20v dc (usually 10 o,clock) Red lead into the coil input wire (NOT HT LEAD) and black lead on frame / battery earth, ignition on and kick over the engine, you should get a quick voltage reading.

Meter sockets, red lead into V/ohms/mA, black lead into COM.


Thanks so much for this jaffa90, im gonna be dusting off the multimeter this weekend and checking all of this out!

Do you have an idea how i would test the voltage from generator? would i set multimeter to 20v dc and put red lead to black/white wire and black lead to battery earth? does that make sense?

thanks again Thumbs Up Thumbs Up
____________________
Cg125 br-k '94
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

Suntan Sid
World Chat Champion



Joined: 07 May 2009
Karma :

PostPosted: 13:08 - 14 Sep 2018    Post subject: Reply with quote

Have you checked/gapped/cleaned the points?
Have you checked the ignition timing?
____________________
"Everybody needs money, that's why they call it money!" Cool
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

bevlak
Two Stroke Sniffer



Joined: 18 Jun 2018
Karma :

PostPosted: 13:14 - 14 Sep 2018    Post subject: Reply with quote

Suntan Sid wrote:
Have you checked/gapped/cleaned the points?
Have you checked the ignition timing?


Yes I have done this, although im not sure if i've done it right... You can't set the timing with the flywheel off, so you've got to fiddle with the contact breaker through a tiny hole in the flywheel - it's possible ive screwed this up, but not sure how to test it. At this stage I just dont know where the problem is stemming from ... even if the ignition timing was a bit off I'd still get at least a shock through the plug no? or a weak spark? I've currently got nothing coning through the spark plug.

thanks for helping out sid Smile
____________________
Cg125 br-k '94
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

Suntan Sid
World Chat Champion



Joined: 07 May 2009
Karma :

PostPosted: 15:49 - 14 Sep 2018    Post subject: Reply with quote

If you type "cg125 no spark" into google, the first result is 5 threads from BCF, have you read all of these?
____________________
"Everybody needs money, that's why they call it money!" Cool
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

bevlak
Two Stroke Sniffer



Joined: 18 Jun 2018
Karma :

PostPosted: 16:46 - 14 Sep 2018    Post subject: Reply with quote

Suntan Sid wrote:
If you type "cg125 no spark" into google, the first result is 5 threads from BCF, have you read all of these?


yep, that was the first thing i did! No luck as yet!
____________________
Cg125 br-k '94
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

jaffa90
World Chat Champion



Joined: 06 Apr 2016
Karma :

PostPosted: 16:54 - 14 Sep 2018    Post subject: Reply with quote

The voltage from the magneto (generator to you) goes to the coil when the points open.
Google is your friend.
 Back to top
View user's profile Send private message You must be logged in to rate posts

Nobby the Bastard
World Chat Champion



Joined: 16 Aug 2013
Karma :

PostPosted: 17:25 - 14 Sep 2018    Post subject: Reply with quote

jaffa90 wrote:
The voltage from the magneto (generator to you) goes to the coil when the points open.
Google is your friend.


Actually the drop in voltage is what generates the spark when the points open. This drop in voltage can go through the coil and be amplifoed.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint 1050 ST
 Back to top
View user's profile Send private message You must be logged in to rate posts

jaffa90
World Chat Champion



Joined: 06 Apr 2016
Karma :

PostPosted: 19:58 - 14 Sep 2018    Post subject: Reply with quote

Lets keep this simple for Sam, when the contact points open the power from the magneto goes to the ignition coil just before the piston reaches the top.
There is also an inline condenser which rarely fails.
 Back to top
View user's profile Send private message You must be logged in to rate posts

Kawasaki Jimbo
World Chat Champion



Joined: 09 Oct 2015
Karma :

PostPosted: 20:44 - 14 Sep 2018    Post subject: Re: Please help! No spark on cg125, I'm so stuck!! Reply with quote

bevlak wrote:
Ok I've got a '94 cg125 I'm turning into a brat/tracker type thing

The bike was running fine and nearly ready,

What had you done to it the day before?
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

bevlak
Two Stroke Sniffer



Joined: 18 Jun 2018
Karma :

PostPosted: 21:11 - 14 Sep 2018    Post subject: Re: Please help! No spark on cg125, I'm so stuck!! Reply with quote

Kawasaki Jimbo wrote:
bevlak wrote:
Ok I've got a '94 cg125 I'm turning into a brat/tracker type thing

The bike was running fine and nearly ready,

What had you done to it the day before?


The day before I had reset the timing. The bike was running better after that so called it a day. Next day it wouldn't start. I've since reset the timing over and over and no luck. This was obviously where I started when the thing stopped running and haven't had any luck with it yet. Maybe I'm making a mistake somewhere but as I said the bike was running well after that initial timing, rode it up and down the street a few times to check all the gears were engaging properly... I'm gonna get on the multimeter tomorrow and report back to everyone here

Thanks for helping Jimbo 👌
____________________
Cg125 br-k '94
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

Kawasaki Jimbo
World Chat Champion



Joined: 09 Oct 2015
Karma :

PostPosted: 21:15 - 14 Sep 2018    Post subject: Reply with quote

Get some leads and try jump starting from a car battery. Car engine off.
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

bevlak
Two Stroke Sniffer



Joined: 18 Jun 2018
Karma :

PostPosted: 21:18 - 14 Sep 2018    Post subject: Reply with quote

Kawasaki Jimbo wrote:
Get some leads and try jump starting from a car battery. Car engine off.


Ok hadn't thought of that... Wouldnt that just tell me if I've got a duff battery? Or am I missing something here?? The battery in there is a slim motobatt one that's fully charged..
____________________
Cg125 br-k '94
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

Kawasaki Jimbo
World Chat Champion



Joined: 09 Oct 2015
Karma :

PostPosted: 21:23 - 14 Sep 2018    Post subject: Reply with quote

Battery state can be deceptive. An attempted jump start from a known good battery nails it one way or the other.
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

Nobby the Bastard
World Chat Champion



Joined: 16 Aug 2013
Karma :

PostPosted: 21:38 - 14 Sep 2018    Post subject: Reply with quote

Doesn't a jump start require a starter motor?
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint 1050 ST
 Back to top
View user's profile Send private message You must be logged in to rate posts

Kawasaki Jimbo
World Chat Champion



Joined: 09 Oct 2015
Karma :

PostPosted: 21:45 - 14 Sep 2018    Post subject: Reply with quote

Nobby the Bastard wrote:
Doesn't a jump start require a starter motor?

It's a kickstart? Shit, you're right!

What is a kickstart anyway? Laughing
Actually that's a serious question. Embarassed Does it need a battery?
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

jaffa90
World Chat Champion



Joined: 06 Apr 2016
Karma :

PostPosted: 21:48 - 14 Sep 2018    Post subject: Reply with quote

Nobby the Bastard wrote:
Doesn't a jump start require a starter motor?

Yes, no starter motor only kick start, also this old bike may not need a battery for a spark.
 Back to top
View user's profile Send private message You must be logged in to rate posts

WD Forte
World Chat Champion



Joined: 17 Jun 2010
Karma :

PostPosted: 00:47 - 15 Sep 2018    Post subject: Reply with quote

Ignore my previous post, thas bollox

Just found this diagram and the black/white wire isn't a DC supply to the coil and points.

Power for the sparks is supplied by the flywheel generator to the points and coil
using a Black/White wire
Its further connection the ignition switch is to allow this power to be grounded
when switched off in order to stop the sparks/engine.

I'd open the the connectors near the coil and points and with a meter set to resistance test the switch opens then closes continuity to ground when operated

Then measure the coils LT resistance to ground which will be low, say 2 ohms or so

Then measure points resistance to ground as you slowly turn the motor
This should go very high when they're open and low as they close
Not too low though,
you'll be reading across the source coil so maybe getting say 100 ohms at a guess.

Probably all academic tho'
As the Op has been fuc.. err 'improving' it, my guess is the points mounting plate has come loose and been pushed away from the cam so the points are permanently shut.

Diagram what I did find, I assume it's the correct one for a BR-K?

https://3.bp.blogspot.com/-a5y9sagbCpI/VQl6R6oZG-I/AAAAAAAAKrg/zN0NfrvjAiw/s1600/002.jpg
____________________
1979 CX500 - Zanussi Wd12: - LG Combi Multiwave - Swan 4 slice toaster with removable crumb tray
 Back to top
View user's profile Send private message You must be logged in to rate posts
Display posts from previous:   

Post new topic   Reply to topic    Bike Chat Forums Index -> The Workshop All times are GMT + 1 Hour
Goto page 1, 2  Next
Page 1 of 2

 
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum

Read the Terms of Use! - Powered by phpBB © phpBB Group
 

Debug Mode: ON - Server: discovery (www) - Page Generation Time: 2.57 Sec - Server Load: 1.48 - MySQL Queries: 16 - CDN Objects: 42 - Page Size: 136.27 Kb