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Bailey V5 ignition coil and CDI

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Pretty sure there are only two types and you are after the 6 pin AC type (battery-less ignition)
Slightly larger than the DC version (if my memory serves)

EBAY: Racing CDI Box Ignition Coil Spark Plug Fit Gy6 50cc 125cc 150cc ATV Moped G7C5U

For the sake of £7 its not worth having a heart attack unless you are in a rush to order one from a UK source.
Are you sure there is a cdi/coil problem on your machine?

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thanks for your answer.
Some explanations:
2 months ago I faced  an engine full stop during a flight.
The stator was the cause of this issue. The ignition coil on the stator burned.
I got one from baley but I also got a chinese one (for the fun)
During 6 flying hours no problem with the one provided by bailey but during the last fly I got the same issue: engine full stop.
Again the stator is dead.
At this point I'm sure that it is an electrical problem.
As I changed already the stator, I 'll change the ignition coil and the CDI.
At this point I replaced the bailey stator by the chinese one and everything seems to be ok but I did'nt isolate the problem.
The ignition coil is quite common so no problem to get one but I hesitate for the CDI.
Is a 50cc or 150cc GY6  CDI the same as what we have on our Bailey V5?
Currently Bailey has no CDI in stock.
You 're right it is a 6 pins AC CDI.
Note that usually a DC CDI is bigger than a AC CDI.
Do you have a mark or a reference noted on your CDI?






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1 hour ago, flyingboxbe said:

The stator was the cause of this issue. The ignition coil on the stator burned.

You have me confused with that statement.

This is a reasonably standard GY6 stator... the white coil is the driver for the ignition and all the other coils would be redundant on a V5.
I don't have the V5 (I have the V2) but it looks to me that Bailey has made a custom lightweight stator and rotor for the V5 which I "assume" is burning out the ignition coils primary windings....?

If this is the case, I would suspect it is possible that Bailey has pushed the limit of the primary coil by designing a higher than standard voltage magneto ignition driver coil and/or using neodymium magnets....? (make starting easier but at wide open throttle the voltage will be high)
"IF" it is the case that you are burning out the "primary winding on the ignition coil" (not the stator winding), you would need to reduce the number of windings on the magneto or move the magnets further away (which ever is easier to implement) but like I said, I have not seen the V5 system.

I cant see the CDI box burning out your ignition coil but I will have to have a think about it.
The CDI is just a timing machine that will open (or shut) the gate between the voltage on the magneto side and the ignition coil so it is the magneto that dictates how much voltage the ignition coil sees and I am assuming that at wide open throttle, it is seeing too much and overstressing the ignition coil.

Ill try to dig out a schematic for the CDI and have a ponder :)

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Scratch all that complexity "IF" you are burning out the secondary winding of your ignition coil.
If your HT lead (between the coil and spark plug) has gone high resistance (poor quality lead) then it may be that, that is causing the secondary winding to heat up and fail.
That would make a "lot" more sense according to Occam and his infamous razor :)
Fit a high quality HT lead!

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1 hour ago, alan_k said:

I replaced my original failed stator recently. My guess is that Bailey just cut off the redundant power coils as a weight saver. 

Ah, maybe the OP "is" talking about a failed stator.....?
Now I think about it, a worn plug, HT lead or bad plug cap would put more stress on all three coils (primary / secondary and the driver)
I still cant see how CDI would play any part in stressing those coils so I still cant see it being the CDI causing a recurring problem.

On a side note, does the V5 still have a flywheel like the following: 
The original GY6 flywheels are heavy... I would have thought the V5 would have got rid and installed something "much" lighter for a pull start machine.

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The flywheel is nothing like the one shown. It is aluminium with fins to give forced air cooling via the cylinder shroud. 

One of the common faults is the thin spade connector on the CDi that is the output to the ignition coil. This has approx 200V pulses on it and unless it is tight with its mating female connector it can develop micro spark erosion. 

Always make sure this pin is particularly tight when mated. 

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13 hours ago, alan_k said:

The flywheel is nothing like the one shown

Thought not... a lot of overkill in those, I have one on my V2.


13 hours ago, alan_k said:

thin spade connector on the CDi

That might be the bugger!
If that spade goes high resistance or intermittent, I guess it could stress the stator.
They are mounted on the crankcase on the V5, lots of vibration. The V2 CDI is mounted on the frame.

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