DC CDI ignition wired to any flywheel that has a magnet.

[Thepartsguy]

I have no clue why he did it that way unless he was confused about engine rotation.
And I wish to make a correction it’s when the magnetic field is broken it fires. When it’s at the center it’s the strongest.

I got your answer! He locked the crank at the position the stock coil fired put his new trigger in the same position! Now think the crankshaft is locked and lined up to the stock coil.

Put the trigger anywhere you want it don’t matter anyways. You would be removing the flywheel key and placing the flywheel back on so it’s at the exact position to send a spark. Lock the flywheel tight with no key then unlock the crank so the piston moves!

 

[bob58o]

Make sure you lap the flywheel/crankshaft taper before doing your final flywheel install without the key.

Still think that after installing the new trigger and flywheel so that the relative spacial relationship between the magnet and trigger are the same as they were with the stock coil, you should check timing with a timing light to make adjustments (either position of trigger, or rotation of flywheel around the locked crankshaft). A slotted bracket for the trigger could make for adjustments that don’t require removing the flywheel.

What timing BTDC are we trying to fire at?

 

[Thepartsguy]

Make sure you lap the flywheel/crankshaft taper before doing your final flywheel install without the key.

Still think that after installing the new trigger and flywheel so that the relative spacial relationship between the magnet and trigger are the same as they were with the stock coil, you should check timing with a timing light to make adjustments (either position of trigger, or rotation of flywheel around the locked crankshaft). A slotted bracket for the trigger could make for adjustments that don’t require removing the flywheel.

What timing BTDC are we trying to fire at?

I was thinking the stock Briggs flywheel fires at 26-28btdc?? I know arcs flywheel bumps that up to 30 degrees Btdc.. I have an adjustable CDI on the way that can add lots of timing earlier in the rpm range.

I was wondering how the guy in the first picture positioned his coil In the middle of the coil posts.

Once the crank was locked to the exact point the stock setup fires as long as the new setup goes on exactly as it‘s firing also then the magnets and coil could mount to the bottom of the engine or the top or side or it doesn’t matter.

 

[bob58o]

Without a timing light, you are still just guessing right maybe +/- like 3 degrees.

And will the adjustable one just have a screw to turn to make adjustments. Still would need a timing light.

 

[Thepartsguy]

Without a timing light, you are still just guessing right maybe +/- like 3 degrees.

And will the adjustable one just have a screw to turn to make adjustments. Still would need a timing light.

Yupp small screw for adjustment. Honestly bumping the arc flywheel back closer to the timing of the stock flywheel wouldn’t be terrible in my opinion.

I can crank in the extra timing as needed after it starts..

 

[Thepartsguy]

I’m watching videos of a guy who sells these cdi’s as a kit and he started the engine revved it and shut it off to

“move the timing”

He loosened the coil moved it ALL THE WAY to the right on the coil mount slots and tightened it back down and started the engine back up. Told viewers to note how the rpm’s DRASTICALLY changed and said moving the coil all the way right would raise wide open throttle and cause a LOSS in off the line torque.

He shut the engine off and loosened the coil and pushed it all the way back over left on the slots tightened it and started the engine. So getting it directly dead on isn’t as important as I’m thinking. He moved it all over the place without a light and that engine sounded AMAZING

Edit: when he moved the coil on the slots he pushed it all the way one way then all the way the other so it‘s not finite..

 

[Rat]

I’m watching videos of a guy who sells these cdi’s as a kit and he started the engine revved it and shut it off to

“move the timing”

He loosened the coil moved it ALL THE WAY to the right on the coil mount slots and tightened it back down and started the engine back up. Told viewers to note how the rpm’s DRASTICALLY changed and said moving the coil all the way right would raise wide open throttle and cause a LOSS in off the line torque.

He shut the engine off and loosened the coil and pushed it all the way back over left on the slots tightened it and started the engine. So getting it directly dead on isn’t as important as I’m thinking. He moved it all over the place without a light and that engine sounded AMAZING

Edit: when he moved the coil on the slots he pushed it all the way one way then all the way the other so it‘s not finite..

All he was doing is the same thing an offset key is for. Moving the coil right retards the the ignition timing, moving left advances it.

With an offset key it would be reverse, offsetting the flywheel clockwise to the shaft (right) advances the timing

 

[Thepartsguy]

All he was doing is the same thing an offset key is for. Moving the coil right retards the the ignition timing, moving left advances it.

With an offset key it would be reverse, offsetting the flywheel clockwise to the shaft (right) advances the timing

exactly! This will make the coil mounting bracket very easy to make now that I can get the pickup away from that right side coil mount post.

 

[Thepartsguy]

Now firing a cdi off the points wire? It would need to be an AC cdi?? I’ve been researching but have only found info bout bolting a stator to the engine and using a gy6 12v regulator/rectifier 12v power out wire to power the dc cdi.

But not to much info on how it all would work fired off the points wire.

 

[Rat]

Now firing a cdi off the points wire? It would need to be an AC cdi?? I’ve been researching but have only found info bout bolting a stator to the engine and using a gy6 12v regulator/rectifier 12v power out wire to power the dc cdi.

But not to much info on how it all would work fired off the points wire.

It is not so simple... with a points/condenser you have to pretty much gut and replace everything after the stator.

That's not a system one can cobble together with random crap, but can be done as an AC or DC system although there is a lot involved with doing either.

Points and condenser share enough similarities with a CDI system that there kits for quite a few antique motorcycles to do such a swap, they are expensive as all hell though.

I was looking into them briefly for my 1970 Honda which used a spring loaded self advancing lobe on one end of the cam shaft to open the points breaker. I happen to like P&C ignitions... except when the breaker gets wet and then fuk'm

 

[Thepartsguy]

I’m making a couple brackets just like Danial Craney uses on his engines.

 

[Thepartsguy]

It is not so simple... with a points/condenser you have to pretty much gut and replace everything after the stator.

That's not a system one can cobble together with random crap, but can be done as an AC or DC system although there is a lot involved with doing either.

Points and condenser share enough similarities with a CDI system that there kits for quite a few antique motorcycles to do such a swap, they are expensive as all hell though.

I was looking into them briefly for my 1970 Honda which used a spring loaded self advancing lobe on one end of the cam shaft to open the points breaker. I happen to like P&C ignitions... except when the breaker gets wet and then fuk'm

 

[Thepartsguy]

I’m back on this with new found direct knowledge from people who have forgotten more then I will ever learn. I have the engine timed with the Cdi pickup correctly now.

The kicker I’m gonna replace the battery with a tecumseh 12v lighting coil. The flywheel magnet powers the lighting coil just long enough for the lighting coil to power the Cdi box and send a spark. When the flywheel isn’t spinning the CDI is not powered.

 

[Thepartsguy]

If I have the Cdi timed properly I’m gonna grab a jug of 60% nitro

 

[Thepartsguy]

 

[Thepartsguy]

I’m guessing these ecu’s are only for spark and possibly air fuel read out.

They are driven off a pickup coil like I have. I know I can hook my pickup coil to a 6al chev box and have rev limiter and two step.

But running the whole ECU? Maybe two pickups are needed? I’ll research more but these engines are EXTREMELY responsive right up to 7k