Discussion on Performance CDIs and Coils By JoeyBee (Read 3,998 times)

[tvnacman]

Jan 27, 2015 21:37:53 GMT -6 @turbotyler said:

Of course the timing should increase whilst giving it more throttle. I'm sorry but I don't know of any engine that doesn't increase in timing with power. Like I said there is only one mechanical fix to the advanced timing. 90gtvert on youtube shows us how to do it the real and only effective way.

How is that?

[JoeyBee]

I think he is referring to the movement of the stator as the mechanical fix. Anyone else have thoughts on this approach?

But overall, very interesting debate. What I am getting from the salty crew here is the CDIs with fixed advancement are pretty much junk. Which makes sense that a "one size fits all" approach is not possible. There a so many independent variables depending on brand and owner modifications.

But the benefit for the wires and coils are possible for a more efficient chamber detonation.

[cyborg]

There may be some improvement with a mechanical "fix" for more high rpm power but it would be slight,,, at the risk of detonation under load at low rpms with large throttle openings on hot days I would imagine ,,,I would prefer a true advancing cdi myself,,, but the gains would be very minor

[rapidjim]

Jan 27, 2015 18:59:14 GMT -6 @turbotyler said:

I though you should remember that the heavier amps etc were the better ones. Same as a computer power supply. The more current a cdi can put out the better spark exactly. That means more mpg. You contradict yourself on this one. Why would I need to take a blue cdi apart for? I can test it on a scoot and tell from there. Also you can expect them to be cheap because they are the cheapest things out there. A stock CDI on 4t' do not have a rev limit. If there happens to be a rev limit on one then it's so far up you shouldn't be running that high of rpm to begin with. When have you ever pinged the rev limiter and needed for it to move up? I have a 150 and a 50 both fully built and fast.

Goodness!!!! Seems you need a lesson in Electronics 101!

The COIL is what produces voltage and current to fire the spark plug NOT the CDI. The CDI is an electronic device that "tells" the coil when to fire the plug, when the cdi "tells" the coil to fire is controlled by the electronics in the CDI. The trigger, that sits above the Rotor (flywheel) "tells" the CDI when to discharge to fire the coil. It does this by a magnet that is attached to the rotor, as the rotor rotates, the magnet moves past the trigger producing a small voltage ( a process called magnetic induction ) that is sent to the CDI, giving the CDI a reference of where the piston, so the electronics in the CDI can "tell" the coil when to fire. That is how the CDI controls timing.

As far as CDIs being rev limited, you must be too young to remember. Actually, it was only a few years ago. Alley is correct when he said the 50cc machines were rev limited (by the cdi) so they would not exceed 25 to 30 mph. In the day (LOL) the cheapest way to get more speed out of a 50cc scooter was to remove the original "Rev limited" CDI and replace it by one that was not rev limited. Maybe you should go back thru the older archives of scooter forums and see for yourself.

Jan 27, 2015 21:09:25 GMT -6 @turbotyler said:

The trike engines are more powerful from the factory because they have to carry all the extra weight. Think about it. Try to add all that weight to a normal 50cc from a trike and see if it will do 30-35 stock. It won't so it's no surprise your trike can have that much more power.

Oh Goodness you are wrong again!

As far as the motor section, Trike motors are standard 139QMB (50cc) 157QMB (150cc) and VOG (300cc) ( some 50cc trikes and scooters did escape China with 44mm pistons and were still labeled 139QMB, shhhh don't tell anyone ). The difference between a scooter motor and a trike motor is in the left motor case, the length of the output shaft and the transmission section. I have dealt with trikes since late 2008.

Jan 27, 2015 21:09:25 GMT -6 @turbotyler said:

There is not magic box. The Kitaco is more expensive just like the NCY one is for a reason. They cannot and do not advance timing as there is only one real way to do that and 90gtvert did it on youtube. If anything the CDI can add spark but it has to be one with better metal inside.

Once again, CDIs DO NOT PRODUCE SPARK!!!!!!!!!!!!!!!!!

[jerryscript]

Jan 27, 2015 21:37:53 GMT -6 @turbotyler said:

Of course the timing should increase whilst giving it more throttle. I'm sorry but I don't know of any engine that doesn't increase in timing with power. Like I said there is only one mechanical fix to the advanced timing. 90gtvert on youtube shows us how to do it the real and only effective way.

There are three ways to advance the timing I can think of off the top of my head. You should really consider taking a small engine course, you may learn a bit more than you have on YouTube.

[JoeyBee]

Brent from 49scooter that make the video in my initial post even states to not take his results as gospel, and certain factors could have influenced his results. Like his timing light was not functioning at 100%. But whatever the case is the knowledge here can be used as a starting point. But the scooter owner has to make their own decisions and mistakes.

[Alleyoop]

To change the timing on a scoot you can:
1. Get an offset woodruff key(you can get them to advance or retard).
2. Slot the pickup coil hold down bracket(to advance or retard).
3. Move the chain on the cam sprocket(to advance or retard).
4. Get a CDI that has advanced timing or one that you can dial in.
Alleyoop

[cyborg]

Aaahhhemm in the real old days,,,, yes I can remember,,, I took my ginko today,,, they had a lever by the steering wheel so you could advance or retard the points plate and was done by a cable before some genius figured out the whole centrifugal weight advancement plate,,, it does help and anything made after like 1950 has it except scooters for some reason,,, mine has it and I'm sure Riches has an advancement curve in the cdi,,,,

[jct842]

Life was so much simpler with a set of points! And not having to explain the device technology replaced them with!

[cyborg]

Oh well ,,,some guys think a few little tweeks and you'll have a rocket on your hands,,,I said it before and repeat,,,,Alleys well thought out and planned build with a decent carb setup a nice stroker WITH a BB kit AND final drive mods makes for a real nice package,,,,smart to go stroker BB with the trike because of the weight,,,and also a plus in Alleys corner is the fact that he used Jim at Rapid Repair to do the build,,nothing like useing a well seasoned Mac with lots of builds under his belt,,,

[Bashan]

This thread is still open for comments and discussion. Feel free to add your thoughts on this topic.

[tvnacman]

in this mans eyes 90gtvert is the be all end all . Perhaps he should show 90gtvert the video and see what his opinion is . It may sway his own .

John

[Alleyoop]

So you all know turbotyler was a seller of the so called KITACO's products or a troll from one of the ODER FORUMS..LOL. He came on toting he had found the GOOSE THAT LAID THE GOLDEN EGG and got shot down and he flew away with the GOOSE and GEESES and SOME kiTACO'S mostly TACOS