Beefed up ignition??

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
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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
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
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Somebody 'round here is working on that....

I'm thinking any 2 wire CDI might work, except we are running 6 volts.

6v CDI suppliers?
 

Pablo

Master Bike Builder & Forum Sponsor
Dec 28, 2007
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Somebody 'round here is working on that....

I'm thinking any 2 wire CDI might work, except we are running 6 volts.

6v CDI suppliers?
Kind of a crappy pulsed 6 volts at that. Low current. Not a ton can be done with it, either. A stronger magneto would be nice, but it also would rob more power from the engine. Worth checking out though.
 

deacon

minor bike philosopher
Jan 15, 2008
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In my new found interest in weedeater type engines I am finding a lot for sale on ebay with burned out coils. I wonder if there is a common thread here somewhere with small engines and magnetos
 
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Norman

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Jan 16, 2008
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Hey I'm looking into to that thanks. Fairracing31. Good info. I can't wait to get down and read it a few times so it will soak in.
Norman
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
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Alrighty experts....is our black box a CDI, a coil, or whut?

Is there a way to close up the gap in the mag a little for a better spark? Norm, airplane guy....what's the deal here?
 

Dave31

Active Member
Mar 1, 2008
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You must be talking to norm, because you know very well Joe I'm no expert.

The CDI (Capacitor Discharge IGNITION) is an electronic ignition that uses a capacitor to store energy to which then gets discharged through the ignition coil. The advantage of a CDI is that the spark energy is very high, you get a very powerful spark. So it's ideal for 2-strokes that would otherwise have fouling plugs.

The disadvantage of the CDI is that the spark is very short in duration. So if the mixture doesnt ignite exactly under spark occurrance, it doesnt get a second chance. To ignite, it has to be right. So the trick is to make a longer spark in duration. Now that's what the Answer Roost Boost used to do. Okay the problem : they are for 12V, second they stopped making them 10 years ago.

Now there's a thing called "CDI Mapping" Which is very new to me and I'm still learning about it. But this is what I got so far.
A 2-stroke, actually responds better when you start retarding the ignition above say 2/3's of its normal rpm. So if a 2-stroke runs up to 9000 rpm, you start retarding from 6000 rpm on up and back down. Advancing up to 6, retarding after 6.

4-strokes dont have that, they advance to a certain point and stay there. The modern 4-strokes have different maps for different throttle settings. They have a different advance, maximum advance for full throttle compared to half throttle or a third throttle or 8% throttle.

So you have different maps for different throttle settings. You can change the delivery of power by changing the map.
 

Norman

LORD VADER Moderator
Jan 16, 2008
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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.rotfl
Norman
 

SeattleMike

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Mar 17, 2008
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I'm no electrical engineer, (and it will be obvious after this question)
Could you hook up 2 CDI's and merge them into one spark plug wire? Hence, <2x the voltage into the plug? I have no idea if this is possible or not, and it sounds like it could likely short everything out or cause a CDI meltdown or fire or something.
Does anyone know what would happen if someone were to do this?
 

Pablo

Master Bike Builder & Forum Sponsor
Dec 28, 2007
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I'm no electrical engineer, (and it will be obvious after this question)
Could you hook up 2 CDI's and merge them into one spark plug wire? Hence, <2x the voltage into the plug? I have no idea if this is possible or not, and it sounds like it could likely short everything out or cause a CDI meltdown or fire or something.
Does anyone know what would happen if someone were to do this?
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!!!!!!!!!!!!!!!
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
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Just a quick update...
I'm still looking into using a CDI & ignition coil from a Honda 80 or something like it. I just have to find something cheap enough that I'm not throwing away a lot of $$$ if it doesn't work.
If other people here could help-out by looking into finding a better mag coil, or even converting to a real motorcycle stator, that would be a big help!

The biggest problems I can see with using a stator are, finding one small enough, & setting the timming!

Come on fellas... we're all mad scientists here! (^)
 
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Dave31

Active Member
Mar 1, 2008
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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. :confused:
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
6,880
905
113
Los Angeles, CA.
I just bought a new Honda C50 CDI & ignition coil from ebay... (all for $20.00 w/ shipping)
I'll have to reserch how to wire them up!
If you guys can keep working on the mag-coil, & I'll figure this one out, we'll all be riding pretty when this is done! (^)

Thanks a lot fellas!! :D
 
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Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
6,880
905
113
Los Angeles, CA.
Just a quick update... I got the new parts, they are actually from a crf50 or xr50... I found a wiring diagram on the web, & I also I ordered a $10.00 wiring harness to trace the wires (just to be sure)
The parts are for a 4-stroke engine, but I think they will still work.
I think the way it works is, it fires on every revolution of the engine, (it just fires a dead spark at the top of the exaust stroke too.)
If anyone knows different, please let me know.
 

Dave31

Active Member
Mar 1, 2008
11,204
42
38
Aztlán, Arizona
Just a quick update... I got the new parts, they are actually from a crf50 or xr50... I found a wiring diagram on the web, & I also I ordered a $10.00 wiring harness to trace the wires (just to be sure)
The parts are for a 4-stroke engine, but I think they will still work.
I think the way it works is, it fires on every revolution of the engine, (it just fires a dead spark at the top of the exaust stroke too.)
If anyone knows different, please let me know.
Isn't the crf & Xr 12 volt? I gave one of my mag's from one of my new kit's to my MSD dealer. He's going to see what he can do with it but I have not spoken to him yet. I'll see if I can get a hold of him today and see if he came up with anything.