Beefed up ignition??

Venice Motor Bikes · #1 03-30-2008, 03:03 PM

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** · #2 03-30-2008, 06:35 PM

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 · #3 03-30-2008, 07:27 PM

Quote:

Originally Posted by Bikeguy Joe

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 · #4 03-30-2008, 07:34 PM

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

**Dave31** · #5 03-30-2008, 09:48 PM

The old Honda's c50/70/90 were 6volt. I'm trying to find upgrades on them which should make it easier. These are 4-strokes, but they say will work fine on a 2-stroke.
check this out JP7 Simple CDI Motorcycle ignition system.

**Norman** · #6 03-30-2008, 10:59 PM

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** · #7 03-31-2008, 07:23 AM

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** · #8 03-31-2008, 03:32 PM

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.

Pablo · #9 03-31-2008, 03:37 PM

That was an EXCELLENT read fairracing31!!

**Norman** · #10 03-31-2008, 06:08 PM

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