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  #1  
Old 15th May 2018, 10:55 PM
datareactor datareactor is offline
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90 posts since Jul 2014
Default Honda Cg 125 engine help needed

Hi Guys

I picked up engine recently. want to build field bike . i have kawasaki trials rolling frame. this engine seems to be 1985-88 Brazilian engine , point based. just want to get in going , no lights required.

Engine seems to have compression.

Current problem:
---------------------

> Flywheel assembly is bit broken , as shown in the first picture.
not sure if repair is possible ?
> One of Coil was heating up. when my friend test.

Question
----------
how to repair the flywheel ? or get new type of stator/magneto .and flywheel
how to get replace the coils .. didnt find any luck on ebay.

Budget is bit tight like always .. want to get the engine going .


Any idea/suggestions are welcome.

Regards

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  #2  
Old 15th May 2018, 11:07 PM
datareactor datareactor is offline
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Original Poster of This Thread Topic Starter
 
Biker.ie Member No. 33474
90 posts since Jul 2014
Default Re: Honda Cg 125 engine help needed

http://ibb.co/fwLXWJ

http://ibb.co/fY4jBJ


http://ibb.co/djPsWJ
http://ibb.co/mmxPdy

Sorry somehow the images are not showing ..
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  #3  
Old 15th May 2018, 11:11 PM
datareactor datareactor is offline
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Original Poster of This Thread Topic Starter
 
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90 posts since Jul 2014
Default Re: Honda Cg 125 engine help needed

Originally Posted by datareactor View Post
first picture.
http://ibb.co/fY4jBJ
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  #4  
Old 16th May 2018, 03:52 PM
scorpy's Avatar
scorpy scorpy is offline
Lurking boogeyman
 
Biker.ie Member No. 5615 from North West
845 posts since May 2007
My Motorcycle Pics Motorbike: XJSXVCRFLH2890
Modifications: Yeah. A few.
Default Re: Honda Cg 125 engine help needed

If the main HT ignition coil connected to the spark plug is heating up it may be wrecked. I assume it's heating up when you kick the engine over. A replacement should be cheap frombut almost any single cylinder coil from any older honda single, motocrosser etc will probably be ok to test it if you can borrow one. If you swap the coil with the lead plug and cap from a working bike as above and you still have no spark, then it's the pickup coil or points. The fact that it's heating up is good news, as there is current coming from somewhere. A HT coil or a bad cap could be the issue but setting as they are usually connected in 1 piece see if you can get one that looks the same from another bike.

One of the 2 coils behind the flywheel is a pickup for the ignition and the other is for the lights and charging system. Obviously for a field bike you don't need both. If it won't spark, swap the 2 over. They are unlikely to be the problem unless there is obvious damage. It looks like the bit you indicate is broken might be ok. I haven't worked on CGs before but I assume that your ignition advance done by spring and centrifuge for the points and as long as both arms can move and return with the spring it should be ok. Check the points are not pitted or very carbonized. And check the points are not earthing onto the mounting plate. Those coils are not cheap new but almost any dipole coil from a dirt bike will do, so if you need one check for a breakers yard replacement.

If it runs badly or fires and dies it may be the timing so you might need a new flywheel but try to get a spark first.

The only place I've found for older coil replacements is http://www.electrexworld.co.uk/acatalog/C25.html

Like I says, not cheap.

Last edited by scorpy; 16th May 2018 at 03:58 PM. Reason: Easier than making a new reply
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  #5  
Old 16th May 2018, 09:08 PM
datareactor datareactor is offline
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Original Poster of This Thread Topic Starter
 
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90 posts since Jul 2014
Default Re: Honda Cg 125 engine help needed

Thanks Scorpy for taking time to reply.

that how we tested .. connect the battery to rotor wires . try to spin the flywheel to see if there is spark in points. one coil was heating up.
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  #6  
Old 16th May 2018, 11:23 PM
Blanka Blanka is offline
MotoGP Legend
 
Biker.ie Member No. 5983
1,138 posts since Jun 2007
Motorbike: fazer
Default Re: Honda Cg 125 engine help needed

There's the workshop manual for it. http://die-kleinkraftrad-ig.de/wisse...itungcg125.pdf
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  #7  
Old 17th May 2018, 12:08 PM
scorpy's Avatar
scorpy scorpy is offline
Lurking boogeyman
 
Biker.ie Member No. 5615 from North West
845 posts since May 2007
My Motorcycle Pics Motorbike: XJSXVCRFLH2890
Modifications: Yeah. A few.
Default Re: Honda Cg 125 engine help needed

Originally Posted by datareactor View Post
Thanks Scorpy for taking time to reply.

that how we tested .. connect the battery to rotor wires . try to spin the flywheel to see if there is spark in points. one coil was heating up.
What battery voltage did you use? That engine won't need a battery to kick out a spark.
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  #8  
Old 17th May 2018, 11:12 PM
datareactor datareactor is offline
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Original Poster of This Thread Topic Starter
 
Biker.ie Member No. 33474
90 posts since Jul 2014
Default Re: Honda Cg 125 engine help needed

we put 12v .. not sure if the coils were 6V. might have toasted the coils?
I agree we dont need battey , but we dont external HT coils at the moment.
sorry bit newbie here

Thanks & Regards
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  #9  
Old 17th May 2018, 11:22 PM
dePeatrick dePeatrick is offline
ISB Contender
 
Biker.ie Member No. 36041
308 posts since Apr 2016
Motorbike: BMW F650
Modifications: Air freshner
Default Re: Honda Cg 125 engine help needed

I have a scrapped CG here but can't be sure of parts but you are welcome to them...
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  #10  
Old 17th May 2018, 11:40 PM
datareactor datareactor is offline
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Original Poster of This Thread Topic Starter
 
Biker.ie Member No. 33474
90 posts since Jul 2014
Default Re: Honda Cg 125 engine help needed

dePeatrick Thanks for your feedback. Appreciate it

Im interested , I can have a look.

if you could give your detail on to my datareactor AT yahoo.com

Regards
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  #11  
Old 17th May 2018, 11:45 PM
dePeatrick dePeatrick is offline
ISB Contender
 
Biker.ie Member No. 36041
308 posts since Apr 2016
Motorbike: BMW F650
Modifications: Air freshner
Default Re: Honda Cg 125 engine help needed

Ok, will do...
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  #12  
Old 20th May 2018, 11:57 PM
Smurf59 Smurf59 is offline
Wobbling Fledgling
 
Biker.ie Member No. 38224 from Ballybofey donegal
11 posts since May 2018
Motorbike: Honda goldwing
Default Re: Honda Cg 125 engine help needed

Originally Posted by datareactor View Post
Hi Guys

I picked up engine recently. want to build field bike . i have kawasaki trials rolling frame. this engine seems to be 1985-88 Brazilian engine , point based. just want to get in going , no lights required.

Engine seems to have compression.

Current problem:
---------------------

> Flywheel assembly is bit broken , as shown in the first picture.
not sure if repair is possible ?
> One of Coil was heating up. when my friend test.

Question
----------
how to repair the flywheel ? or get new type of stator/magneto .and flywheel
how to get replace the coils .. didnt find any luck on ebay.

Budget is bit tight like always .. want to get the engine going .


Any idea/suggestions are welcome.

Regards

Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.
Hi eBay item number 123127984799 going cheap
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  #13  
Old 20th May 2018, 11:58 PM
Smurf59 Smurf59 is offline
Wobbling Fledgling
 
Biker.ie Member No. 38224 from Ballybofey donegal
11 posts since May 2018
Motorbike: Honda goldwing
Default Re: Honda Cg 125 engine help needed

Hi there EBay. Item number 123127984799 going cheap
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