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Symptoms of LT coil breaking down?
Posted: Sat Jul 25, 2009 5:16 pm
by soullad
I think this is happening to my engine.....it just doesn't like any load placed on it and then 4 strokes madly.....
is this the LT coil breaking down?
Re: Symptoms of LT coil breaking down?
Posted: Sat Jul 25, 2009 6:20 pm
by J1MS
Can be a symptom, accompanied with extra effort to kick it over and sometimes a poor tickover...
Re: Symptoms of LT coil breaking down?
Posted: Sat Jul 25, 2009 10:37 pm
by firekdp
It could be any part of the ignition circuit that would cause a weak spark, LT coil, HT coil, plug (plug gap), HT lead etc.
Re: Symptoms of LT coil breaking down?
Posted: Sat Jul 25, 2009 10:47 pm
by soullad
I've changed HT lead, cap and spark plug plus CDI..........
Jims - it ticks over nice and regular but its always been a tad difficult to kick over so not sure if this has altered at all - also why would you say this?
Re: Symptoms of LT coil breaking down?
Posted: Sat Jul 25, 2009 11:01 pm
by Dazza
When mine went , it got me home with not the slightest hint of a problem, then wouldn't start the next morning

Re: Symptoms of LT coil breaking down?
Posted: Sat Jul 25, 2009 11:18 pm
by J1MS
soullad wrote:I've changed HT lead, cap and spark plug plus CDI..........
Jims - it ticks over nice and regular but its always been a tad difficult to kick over so not sure if this has altered at all - also why would you say this?
A poor tick over can be a symptom on a previously smooth running engine as this sometimes happens just prior to the LT coil shorting out completly, owing to a slightly reduced charge from a failing LT coil... Earth wires can also give a perfect reading but engine vibration can cause an intermittent or poor earth at tick over and lower revs, as the engine vibration is more noticeable and its the vibration that will add to a poor connection at the earth tag on the stator, or any connection between LT and the Spark plug... Thats my reasoning for a poor tick over sometimes being a symptom... As Dazza says his got him home then wouldnt start, as its usually poor starting thats the first problem to show up with a failing LT coil...
Re: Symptoms of LT coil breaking down?
Posted: Sun Jul 26, 2009 12:17 pm
by soullad
Right, thought i'd approach this with a fresh mind so first thing this morning started it up.........choke on, and it starts first kick ???????
set off up the road and it seems fine unti i get past 1/4 to 1/2 throttle........so maybe i was confusing load or rpms with throttle setting which would lead me to thinking its an issue with the carb. But I haven't changed a thing carb wise and only cleaned it out thoroughly the other day.......
reeds fine, piston and rings new.................

Re: Symptoms of LT coil breaking down?
Posted: Sun Jul 26, 2009 12:33 pm
by oldbiker
set off up the road and it seems fine unti i get past 1/4 to 1/2 throttle........so maybe i was confusing load or rpms with throttle setting which would lead me to thinking its an issue with the carb. But I haven't changed a thing carb wise and only cleaned it out thoroughly the other day.......
reeds fine, piston and rings new.................

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1/4 to 1/2 throttle is when the main jet actualy starts to do its job, the fact that the scoot worked ok prior to cleaning the carb surgests that the carb is at fault.
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have you blocked the main jet, atomiser or one of the small airways in the carb body??
did you clean the carb because you knew that you already had a problem with crap in the tank or fuel line??
just an idea
Re: Symptoms of LT coil breaking down?
Posted: Sun Jul 26, 2009 7:16 pm
by soullad
Yeah, i cleaned the carb because of the poor running and it made no difference. The main jet hasn't changed.........Im also running an inline filter which is clear.
Maybe one more clean of the carb then its time for a new stator, unless anyone knows where I can get BGM coils /pick ups?
Re: Symptoms of LT coil breaking down?
Posted: Mon Jul 27, 2009 1:28 pm
by coaster
Have you measured the resistance through your LT coil? I have just measured my BGM which I haven't fitted yet and get 513 ohms on the HT coil (green and earth) and 111.6 ohms across the pickup (red and earth). Yours should be somewhere near those.