Beefed up ignition??

[Andy]

Could we just run a 12v CDI module in loss mode? Power it from a rechargeable battery. I was reading the post on the Walbro carburetor, and ended up on an RC airplane engine page here. They run their engines without an alternator or magneto, just use a NiCad and have no problems.

This way you could use the pulse wire from the engine and a hi output CDI.

Then you can get into crazy stuff like using the Shimano hub generator and a voltage booster to kick the 6v upto 12 volts using a voltage booster.

But, take all of this with a grain of salt, I am still mounting my engine, so this kind of performance mod is waaaayy down on my list.

Andy-

 

[Goat Herder]

has anybody checked the voltage of these? I measured two bikes from seperat supliers each at idle gave 10 volts when reved it whent to 12 easly ? Ive had extrordiary luck whit my direct hit by the way 40 teeth got me to 42 miles an hour! Not smart on one of these bikes but I did it in a safe place.

 

[Walter F.]

I'm still working on it when I have time, still no luck. I have given up on finding something to fit. The Honda C50 is the closest thing I have found.
I wonder how to go from 6v to 12v. I know how to do it in a car, but not a motorcycle. If we can get 12v, that would open the door for us, maybe.

You can do it with a "step up" transformer 6v up 12v but amps are cut in half. You can do it with batteries wired in series again 1/2 the amps.

In old cars we used a "step down" resistor, so we could use a 12v battery and keep 6v starter and all bulbs. We just put in a 12v generator & voltage regulator Walter F.

 

[Goat Herder]

The DirectHits | Pulstar Pulse Plugs, is a step up transformer

 

[n7net]

When I was a kid with my first car the routine was check the gas and fill it up with oil. Plugs fouled on a regular basis, so I stood the wires off from the plugs about a quarter-inch. That created a hotter spark and kept the oil burned off the plugs. I don't know if that will work for you.

Scott in Texas said that

Wasn't there something about the coil windings using more with smaller gauge wire or was it less with a larger gauge wire? Heck I've got to do more reading on it. I'm now wondering if a guy couldn't rewind the mag's coil and get a better light? All this sounds like more work than I'm wanting to do I think I'll go ride the Harley. Chris is supposed to be sending me a cdi and I'll send him a light for the cdi so I can tear it apart and see whats inside. I'll have fun, fun, fun, until Bob take the blowtorch away. Sounds like a Beach boy song.
Norman

 

[jasonh]

I've been doing a little research on stuff we could use for these motors, so I figured I'd post what I've found so far. Sorry about the organization, I'm just pasting excerpts from some posts I've made. Some may be new info, some old, who knows.

I've been looking for a replacement CDI, but ours is not the traditional CDI. Most CDI's have a constant power source and constant ground, and it receives a "fire signal" coming from a secondary magnet/coil (or hall-effect sensor, or optical sensor, or even mechanical points) on the flywheel...in other words they use a minimum of 3 wires, unlike our 2.

Tj, the only problem with that CDI you posted, is our motors don't have a separate trigger coil. Most CDI systems have a charging coil and a trigger coil on the motor. We just have a single coil. So ours works a bit differently. I'm still trying to figure out exactly how...we may have something similar to the Briggs Magnetron system, but I haven't verified that yet. Once I get my new magneto and CDI in and I verify the bike works, I might rip into my old CDI and see what's up.

I know I have posted an animation and other info on the Briggs-type system, I just can't find it right now

 

[jasonh]

ok here we go. First off,

http://motorbicycling.com/f34/cdi-test-help-verify-my-results-2118.html

is where the following is from.

Magnetos output AC.

Yes, they are called CDI's as in capacitor-discharge-ignition. My beef currently is I cannot find anything about a real CDI that only has 2 wires. Everything I can find basically says this:

A CDI will take a constant power source and keep a charge inside. Then it gets a pulse signal from the motor and releases all that energy into the coil which then steps up the voltage big time and that gets output to the plug which has your lovely little spark.

We only have a power and ground on these, so I don't see how exactly they would work short of just acting like a normal coil and sending out a zap every time the magneto spins around and makes a pulse o' power.

Not to mention, how are these "CDI's" so darn cheap? I can't find cheap Chinese CDI's for under $50-75.

Right now I'm actually wondering it basically charges on the + pulse from the magneto, and then the - signal from the magneto is the extra "trigger" pulse. That seems like it could be logical, but I can't seem to find any info on anything similar.

Any ideas on what kind of ignition mowers use?

So I've been Googling like mad, and I think I may be on to something. It kind of looks like our ignition system is similar to the Briggs Magnetron system, but the trigger coil is our magneto. Which brings me around full circle wondering why the heck this test doesn't work. Some info on the Magnetron system:

The Magnetron Ignition System - Learning Activity
Timing is Everything - Basic Kart Ignition Explained, Part 2 - Article by John Copeland (first half of article)

Hopefully this helps us get somewhere with our ignition systems...

 

[Venice Motor Bikes]

Here's the low-down:
Most CDIs utilize a small coil to trigger when the CDI dumps its voltage to the ignition coil.
Our little chinas utilize a simpler 2 wire, one coil system. A Kawasaki KDX CDI is also a 2 wire type but it gets around 200 volts from the magneto coil, whereas our chinas put out around 50 volts. The positive half of the AC voltage coming from the coil is used to charge up a 1.5uf capacitor in the CDI, then the negative half of the AC voltage is used to trigger the CDI to send a momentary pulse of that same voltage to the step-up transformer which then outputs a spike of thousands of volts to the spark plug.
All we can do to improve this ignition system on the HT is increase the voltage going to the CDI/ignition-coil combo and hope it doesn't fry it. If it does then we'll have to utilize a KDX CDI and ignition coil. But then something may have to be done to get the timing back to normal if it is off.

Try it & post the results here!!!
(The ignition on these engines is still one of the few things that has NEVER really been improved!)

 

[thine82]

why cant we install a second magneto over top the first one with a second coil pack to get the voltage we need to run lights??? like a double system.. i need a magneto to try it.. i have a secondary coil pack but would i need another cdi pack? no on the cdi pack i think..

 

[Venice Motor Bikes]

why cant we install a second magneto over top the first one with a second coil pack to get the voltage we need to run lights??? like a double system.. i need a magneto to try it.. i have a secondary coil pack but would i need another cdi pack? no on the cdi pack i think..

There's someone who makes & sells them on fleabay! There's a thread on here about them somewhere.

 

[kipharley]

Does anyone know of a way to beef-up the ignition in the Chinese engines?
I've replaced the boot, wire & plug with better ones.
I also solder all the wires (NO crimps!)
Now, I want to replace the CDI & magnito with better ones... Any ideas?

Thanx,
Norm

Hi,Norm.I'm working on a modification upgrade.,To the whole system!Kip.
[email protected]

 

[Venice Motor Bikes]

It's been almost 3 years since I started this thread & we're STILL trying to find a better ignition system?!?!

Hopefully with some new blood, will come some new ideas; & we'll finally have this problem solved!!

 

[mbuna420]

hmmmm I think I will get one and try this too

 

[hsvmick]

You may end up with no spark......probably not a fire, just the magneto couldn't support 2X the current draw (1/2 the resistance) and charge the capacitors....but if it could - I wonder how close in timing they would be....and then well....maybe it would fry one CDI
first......hm.....

NORMAN TRY THIS!!!!!!!!!!!!!!!

i have tried this on a methanol stock car resulted giving a 3hp increase only costing a 50buck out lay 1foot of wire tube of epoxy and a gt performance coil and 5mins of time so it s cheap for a 3hp jump spark but will it bounce our china girl any better...... with the glue drop it inside where the lead screws in and let it go hard plus to + and ground to- and the boot will transform a reverse cycle meaning a increase in spark '''''''';;;;.....??

 

[hwybikedon]

Hey, where did everyone go in this? Was this ever done?

We use this on a friends Yamaha 2 stroke, yes the bike has plug and play connections tho. The kit came with instructions and mapping of the plugs input and output supply lines and what they run! Hmmmmm. Just a thought no expert here.

A small step up transformer may work.

I do build V regulators 0 to 50V for DC applicatoins. It's as big as my hand and very light.

Yes i'm off work for two or more weeks with a broken arm. Getting all my hunny dews done and looking for things to do. Hope I can help.

 

[ivan H]

​

ok I only read the first 3 pages & there's a misconception that the cdi in these is 6 volt. The white lighting wire is, the stator for the cdi puts out well over 200.. Its a 2 wire cdi where the positive half of the AC volate (rectified) charges the capacitor, as it goes negative it triggers the scr in the cdi into conducting allowing the capacitor to discharge into the ignition coil. Now the stator admittadly doesnt put out much current but I dont think its the problem, more the crappy H T lead & plug boot, & maybe the coil, plus cdi doesnt retard at higher rpm. On the last page of the thread modified cdi & cr80 coil is a schematic & writeup on a cdi I have used for quite some time with good results. Rohmell printed a better of the schematic in the thread roll your own cdi on the last page. Give it a whirl. U will need a coil of a small mx bike. Cheers

 

[BigBlue]

Ivan H,

has anyone ever thought of using the Jaycar CDI kit - It's made right there in Australia.

Here's an article describing its operation and design:

http://www.siliconchip.com.au/cms/A_110499/article.html

Here's a seller for $21.95:

http://www.performanceautochip.com/category_s/204.htm

Good Luck,

Chris
AKA: BigBlue

 

[ivan H]

Sorry 4 taking so long 2 answer. I live in oz & get my electronic components from jaycar & while that CDI is well designed it wont work as its the much more commonly used type that is triggered by a seperate low voltage triggering coil, a 3 input wire CDI, as opposed to the 2 wire CDI these use. Cheers

 

[crmachineman]

Hey everybody! I just finished installing a DC fired CDI. It does make quite a strong looking blue spark; however, I have not really noticed any performance increase. I must note that my engine is still far from where I want it. I think the compression needs to be increased quite a bit. Maybe a strong ignition system will benefit a high compression engine more than a low compression engine, which is what I basically have right now. Since it is a DC fired system, I have to tote a battery along. Fortunately my seat design allows ample space for the electrical gear required. I purchased the CDI unit from Scrappy Dog Scooters. I'm starting to experiment with the base timing setting by moving the magneto magnet position on the shaft, using a technique that the guy from Creative Engineering illustrated in a past post. Here's some pictures of the somewhat mediocre installation.
Thanks,
-Fred

 

[ivan H]

2 strokes should have ignition advancing up 2 about 2/3 of max rpm then start retarding it for best performance. I think the jag cdi has initial firing point at about 19 degrees BTDC. With the cdi I made myself I have it aa little more advanced than that. Ur plugs center electrode should have a covering of oxide all over the side of. If 2 advanced the very tip of will have a band of bare metal about 1/2mm wide where the heat of advanced firing has burnt the oxide off. Cheers