gy6 moto coil? anyone tried?

[briane]

hey all,

I'm trying to find a decent coil so I can build my own CDI circuit and play around with timing curves and components.

Anyone used this gy6 before? would it work on a skyhawk 2012 with an appropriate CDI?

I've tried the jaguar - prolly just me cause I hear everyone has great results - but my jag CDI lasted about 5 rides before it died - so Im not impressed or going that route anymore - I'm gonna have to build my own I think. Also the jag is built around top speed, not low end torque - and I need that torque to get up hills - so not only the quality issue, but that jag didnt do what I wanted it to. clearly I need to design my own. sorry jag - I really respect your info but it did not work for me.

and yes - I am an electronics guy who designs his own circuits - I figure if I just get the coil I can build my own electronics. So yes, the jag was installed correctly, and had no broken wires.

oh - just noticed jnm has a warranty on that jag cdi - maybe I just got a faulty one?

still want to build my own.

ps - I've built most of the consumer grade electronics in my home - this is basic stuff once I figure out what needs to be done

 

[Fabian]

and yes - I am an electronics guy who designs his own circuits - I figure if I just get the coil I can build my own electronics.

Can you design and manufacture a CDI and coil that uses a graphical interface to steplessly adjust the ignition timing curve, and most importantly runs a twin spark plug cylinder head.
I have a burning requirement (sorry the pun) for a CDI/coil that can perform this function.

 

[briane]

Can you design and manufacture a CDI and coil that uses a graphical interface to steplessly adjust the ignition timing curve, and most importantly runs a twin spark plug cylinder head.
I have a burning requirement (sorry the pun) for a CDI/coil that can perform this function.

sorry - I probably should have labeled this thread ' what coil can I use to learn to design a CDI around' - I dont mean to come across as a know it all, just tryiing to say I'm not totally out of my boat here - but yes I recognize and value the experience you all have. I thought this would be a fun electronic tuning project for me.

sorry fabian - that wasnt my intent - I just want a bigger spark and maybe the stock low end timing curve - and some electronics I can muck with. I have since realized that aside from hotter spark the best way for low end torque might be a sproket change. no, I dont want a gui on the thing - though it would be cool - Im fine with resistors and caps.

thanks sublunacy, I'll look into the mitsubishi coil.

 

[Fabian]

the best way for low end torque might be a sproket change.

How much more torque do you need?

 

[briane]

i was going to say lets do this/ im still there but we should look at jags timing graph and see if there is room for improvent/also just use jags little coil and work from there....

yeah - truthfully I was going to start with jags ideas - I dont want to re-invent the wheel, I just want it to help me grind up seattles crazy hills. I had though ripping apart a stock cdi - and bypassing the coil to a larger one would be a start - but I also dont want to 'steal' someone elses invention (ie. thanks jag for the schematic - occured to me I'd learn a lot building one and messing with values a little bit)....Though this is all personal use and sharing to me. Im interested in the single/double pickup cdi (is this the 2 stroke/ 4stroke timing difference?) issue so I'll have to read up on that.

also - regarding the .3 ohm rotor - are you saying say a .5 or 1 ohm would have better spark? Then to me since this could potentially become an experiment in excess - if cost and size were immaterial - whats the best ohmage for these little 2-stroke 66cc chinese engines?

I recall jags cdi did work really great on the top end of the acceleration.

 

[Fabian]

How much more torque do you need?

 

[Fabian]

i was going to say lets do this/ im still there but we should look at jags timing graph and see if there is room for improvent/also just use jags little coil and work from there....

If you make a new CDI, i'll get out my credit card and buy the thing ASAP, because i'm curious to see how someone else's idea works out in practice.

 

[HeadSmess]

is the jag still built on veroboard and unpotted?



not saying what components go where

the "lighting coil" is heavy guage, wound from the earth tap to the white wire.

the "charge" coil is finer guage, starts at the white wire tap, and continues on to the blue wire.

any fluctuations in the load on the lighting coil will affect the timing on the cdi, to the point of not running most of the time.

dont use the white lighting coil. well, you can but usually its a waste of time.

the cdi operates by charging capacitor on the positive swing, triggering and discharging at a certain voltage on the negative swing.

theres plenty of ways to vary that timing... the CR circuit seems to be the way someone posted it in a forum somewhere, and whats been used on the available models. its easy, doesnt require an abundance of parts.

theres other ways.


back to the main question. what coils work? so far, on my simple unretarded cdi, ive managed to get anything from a 2.4v mains transformer in reverse, a car coil, the old points type, a new car coil, a pitbike coil, the flyback from an old HF welder starter, the flyback from a telly, a postie bike coil, and even just an old solenoid coil with a few turns of wire round it as a primary!


and, so far... with four different cdi's and various retard/advance curves... nothings beating the basic 8 component CDI circuit.

(this isnt it, but close)

 

[HeadSmess]

ill also add. its not my circuit. that ones of russian heritage i believe.

the minor difference between it and what i use is to change the resistors to just 82R and 18R in series, centre "tap" being "wiper" on trimpot shown... 82 goes on the "black wire" side, 18 to the junction of diodes and thyristor cathode. use 1watt.

thanks to "rohmell".

it is a pretty standard circuit though. cant give that much credit. found it in flash tube drivers, fence chargers, etc... i even have a novelty lighter that has one inside for zapping the unwary! oh, the time i got the boss after he had just washed his hands

i figured a way to increase the advance drastically by changing one component. i think. i need a scope and to actually assemble such a beasty to verify designing PCB's is all good and well, but redesigning circuits and making sure they work is more important!

youll find starting is much easier as spark energy is increased. a much more effective circuit.

this one produces sparks powered from 15v tap on a mains transformer, the stock HT just starts at 60! works to check, but dont run too long as the current drain on the negative cycle overloads the resistors. it was a 5 amp transformer though...

also, theres talk of using the rest of the negative cycle to use as a 12v power supply. the thyristor uses a poofteenth of the energy produced to trigger.

im working on this. i didnt like the example shown... same as that white wire coil i talked of...changes trigger voltages, affects timing. needs to be "isolated" somewhat.


all this adds to the size and complexity of the board.

for playing around, heres a basic board...



outputs on left hand side from top are black blue coil.

schematic



feel free to play with the 47R, 560 R, and the 2.2uf... or even remove em

 

[HeadSmess]

im more interested in ignoring any existing graph, and doing comprehensive dyno tests to get the best graph.

meanwhile, i have a concrete ring to repair. and an agitator motor. gotta pay for food somehow. grrr.