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Discussion Starter · #1 ·
Anyone with any ideas as what my problem can be ?

So lost front cylinder, done the usual stuff. Plug drain, new plugs, coil, lead and it started working....for about 25 miles. Lost it again. In the end, ended up changing CDI unit, and on a first turn......she was running sweet as on both cylinders.....for about 25 miles. Again, checked the lot and no issues with the coil, plug or lead found.
Further testing.....12v on the coil is OK when meter to the orange/white coil wire and frame.

Anyone had an idea where exactly is the blue/white (other one to the coil) going to through harness ?

Am i right thinking the coil has 12v constant supply when ignition on and CDI unit just sends the negative?

Any help is much appreciated
Thanks
 

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Have you replaced the sparkplug cap?
 

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I'll get that replaced this week together with yet another coil and will update , but thats one thing I didn't replace yet 🤔
Pretty common for that to be the issue. Hope it fixes it for you.
 

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Are you sure it's the spark that is cutting out? Have you checked air/fuel is getting in?

I know you don't have carbs, but my 1st gen, I had fuel starvation on the front cylinder from dirty jets.
 

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I'm guessing fowled plug, from stuck or faulty choke/cable
Second gen SVs are fuel injected and do not have a choke, but sometimes they can foul plugs.

It used to be that my first instinct on a second gen was the ignition system, but as these bikes get older, issues with the fuel system have become more common.

The most common thing is a clogged high pressure fuel filter (not the sock on the end of the fuel pump) which leads to low fuel flow and/or low pressure.

Some interpid SVriders have experimented and found that the SV will run with far less than the specified amount of fuel pressure.

But, if you imagine using a spray bottle or squirt gun, if you pull the trigger fast you get this nice stream or mist, but if you pull the trigger slowly, you get a dribble.

Your injectors do the same thing. Low fuel pressure or flow means the injectors dribble fuel into the port instead of spraying a fine mist. At low air velocities like idle, a dribble of liquid fuel won't burn as well as a mist. That's how you end up fuel fouling the plugs.

To the OP, yes the coils are supplied a constant 12V and are grounded by the CDI(ECU/ECM) when it wants a spark.
 

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Discussion Starter · #9 ·
Thanks for the input guys!!!

Update on progress.......none , still nothing.

Changed coil, lead and spark plug boot today, fired up and still no 1st cylinder.
Taking into account the previous issue where I had to change CDI which cured it (for 20+ miles), I'm starting to think this CDI is gone as well. My thinking would be......if the rectifier was knackered and putting over voltage to CDI or any relevant part of ignition, could that be a cause? Which would mean new rectifier and CDI unit again?

I've checked the fuel issue, I'm getting wet plug. Also went and swapped the injectors and the problem didn't transfer to the other cylinder.
 
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