Manky Monkey Motors

Technical Section => Bike Tech => Topic started by: WAYNE999 on November 13, 2011, 07:34:37 PM



Title: old honda cg destroying spark plugs
Post by: WAYNE999 on November 13, 2011, 07:34:37 PM
I've just bought a very pretty 1978 Honda CG125.It was running when I said I'd have it but I went to pick it up and it wouldn't start.
Very quickly found the fault to be a knackered spark plug (no spark with the original plug spark with a different plug).
So yesterday changed spark plug 2 kicks it started ran for a couple of minutes then I switched it off.
This morning it started first kick I thought all was well ran it for 5 minutes then turned it off
This afternoon tried to start it nothing took the plug out no spark used a different plug got a spark cleaned the plug up but then it was sparking all over the place has any one any ideas could it be the condenser that's at fault?


Title: Re: old honda cg destroying spark plugs
Post by: spanners on November 13, 2011, 07:52:19 PM
doesnt sound like a condensor fault could be coil,,

what colour is the spark when you have one ???

what gap have you got ?????

how are you ,cleaning, the plugs some wire bruhses leave metallic residue on the ,pot, in the plug causing the to short or ,fizz,

also some plug blasters do the same..


Title: Re: old honda cg destroying spark plugs
Post by: Bus Boy on November 13, 2011, 07:56:18 PM
i was about to say coil as well .


Title: Re: old honda cg destroying spark plugs
Post by: spanners on November 13, 2011, 07:58:00 PM
great ------ NO  old minds think alike  :D :D


Title: Re: old honda cg destroying spark plugs
Post by: Bus Boy on November 13, 2011, 08:20:18 PM
less of the old!


Title: Re: old honda cg destroying spark plugs
Post by: Cabman77 on November 13, 2011, 08:52:51 PM
could be almost anything. Could be burning oil and the deposits are getting up inside the plug. Ignitor box breaking down, a likely answer. Or as the others have said the coil is knackered. If I had to choose I`d say the ignitor (I think all the CG125`s had them).  ;D ;D ;D ;D


Title: Re: old honda cg destroying spark plugs
Post by: WAYNE999 on November 13, 2011, 08:56:29 PM
doesnt sound like a condensor fault could be coil,,

what colour is the spark when you have one ???

what gap have you got ?????

how are you ,cleaning, the plugs some wire bruhses leave metallic residue on the ,pot, in the plug causing the to short or ,fizz,

also some plug blasters do the same..
the spark is a yellowy orange colour hope this helps


Title: Re: old honda cg destroying spark plugs
Post by: WAYNE999 on November 13, 2011, 08:58:57 PM
could be almost anything. Could be burning oil and the deposits are getting up inside the plug. Ignitor box breaking down, a likely answer. Or as the others have said the coil is knackered. If I had to choose I`d say the ignitor (I think all the CG125`s had them).  ;D ;D ;D ;D
I've never heard of an ignitor where would I find it?


Title: Re: old honda cg destroying spark plugs
Post by: Cabman77 on November 13, 2011, 09:02:41 PM
somewhere under the seat, black plastic unit. Should have two sets of leads  plugging into it but as it`s a single it may only have the one plug. There is nothing you can do with them, but if you can borrow one to try it may give you an answer to the problem. One thing, if you`ve got points you won`t have an ignitor, but I`m almost certain the CG models all had them.


Title: Re: old honda cg destroying spark plugs
Post by: WAYNE999 on November 13, 2011, 09:14:17 PM
somewhere under the seat, black plastic unit. Should have two sets of leads  plugging into it but as it`s a single it may only have the one plug. There is nothing you can do with them, but if you can borrow one to try it may give you an answer to the problem. One thing, if you`ve got points you won`t have an ignitor, but I`m almost certain the CG models all had them.

Its a contacter points model phew!!!! thats one thing less to worry about.Thinking about ignition service points,condenser,coil,ht lead,suppressor cap and plug just be nice to know which bit's buggered


Title: Re: old honda cg destroying spark plugs
Post by: spanners on November 13, 2011, 09:29:54 PM
somewhere under the seat, black plastic unit. Should have two sets of leads  plugging into it but as it`s a single it may only have the one plug. There is nothing you can do with them, but if you can borrow one to try it may give you an answer to the problem. One thing, if you`ve got points you won`t have an ignitor, but I`m almost certain the CG models all had them.

Its a contacter points model phew!!!! thats one thing less to worry about.Thinking about ignition service points,condenser,coil,ht lead,suppressor cap and plug just be nice to know which bit's buggered

suppressor type plug cap ::)
take it off strip back half inch of bare wire and connect straight to a clean plug and see what colour spark you have now it should be clan brigh blue sort of sharp lookin

also give the points a good clean and regap them at around 12 to 16 thou ,if i remember right ,,

and see what youve got


Title: Re: old honda cg destroying spark plugs
Post by: Dslam on November 14, 2011, 01:57:11 PM
Those early CG's had a metal shrouded suppressor/plug cap which were forever causing intermittent spark problems. If it still has the metal cap you can peel the metal shroud off with some snipe nosed pliers.


Title: Re: old honda cg destroying spark plugs
Post by: nabsim on November 30, 2011, 01:48:03 PM
I remember one Yam I had always had to have new plugs. Wouldn't run on cleaned plugs, dont ask me why or how it knew the difference. Had loads of stick of a mate who kept trying to tell me they could be temramental and had to have new plugs. Was most annoying when that fixed it :)


Title: Re: old honda cg destroying spark plugs
Post by: BikerGran on November 30, 2011, 03:37:01 PM
I used to burn the muck off my Yam stroker plug by holding it over the gas flame as just brushing didn't do the trick.


Title: Re: old honda cg destroying spark plugs
Post by: WAYNE999 on December 02, 2011, 09:57:09 PM
thought to myself f*** it if i change everything i cant be wrong so new plug,cap,ht lead,coil and condensor been running daily for a fortnight with no problems ;D