Jaguar & Lightning CDI timing curves

  • Thread starter Deleted member 12676
  • Start date
the only CDIs causing engines to go up in flames is the stock CDI (on the engine in the following picture) and the Lightning CDI because both have overly advanced ignition which increases engine temperature and contributes to engine-destroying detonation.
burning.jpg
The wire size on the Jaguar is adequate if you don't leave the wires flapping in the wind. The length is now being made longer.
Components are imported from the States, same quality. (The topic of components has already been gone over in another post.)
As always the competition doesn't talk technology or about the engineering reasons for ignition timing curves, just little nit-picky stuff that equates to school children making fun of each other for little clothing differences.
Of all people to take the side of a CDI with incorrect timing curve I wouldn't think it would be a race promoter! backwards world
 
I've seen that picture. The guy apparently spilt/leaked fuel onto his hot motor. I think this is where the "Junkuar" CDI gets it's magic smoke from.

People have had problems (and I only looked a 2 pages of search results).

"My problem with Jaguars CDI is that i bought it from him and after the internals came un-soldered he tells me to go to JNM to complain. Well guess what, JNM didn't sell me the CDI. It's a shame they (JNM) claim how much more reliable the Jaguar Racing CDI is over the stock. Jag's works better but is not more reliable. I find myself torn. I can't repair mine for the life of me because my soldering skills suck. However my father in law builds computers, i think my solution is simple. I'll have him reman the current model and replicate a few more for back ups. "
http://www.motoredbikes.com/showthre...CDI-Coil/page4

"I bought a JAG CDI last month and finished my bike a week or so ago. The CDI lasted about 1 minute and died."
http://www.motoredbikes.com/showthre...arranty-return

Just build your own (look in my album). An incorrectly adjusted Junkuar CDI can do more damage, sooner.
 
el, an engine has to be hotter than is a normal maximum to ignite fuel that leaks onto it.
both advanced ignition and high compression contribute to excessive engine temperatures.
The Jaguar CDI retards the ignition back to where it should be to not contribute to excessive engine temps.
Yes it had a reliability problem that has been solved. I am well aware of that. All assembly now is under my watchful eye (as an electronics technician since 1977) and I personally test each one to make sure its timing advances and then retards as the RPM rises.
None of my competition has this kind of tester. I know because they aren't commercially available. I designed and made my own.
So when you buy a competitors CDI you can't be sure if its timing curve is functioning. Maybe its not but you don't know better since all you have to compare it to is the standard CDI.
 
gasoline auto ignites at around 400, doesn't it? if some of that spill landed on the header it would be up in flames with or without a jaguar cdi

wouldn't a timing light and an engine be the only test equipment you need to determine the timing curve? both of those are not only commercially available, but in just about every garage
 
yes it's true that if the gas dripped onto the header that would be enough to light it. But if it lit by contact with the head that means the head was at least 495 degrees which is too hot for an aluminum head. It can crack and warp at that temp.
yes the CDI's could be somewhat tested on an engine but I highly doubt the makers are going to that much trouble.
 
jaguar said:
I finally got hold of a Lightning CDI to test it against a Jaguar Performance CDI on the bench. Below is a graph showing the timing curve difference.
View attachment 52272
The spark strength of the two is the same, using the same high voltage coil. The main difference is that the Jaguar CDI retards the timing at a higher rate than the Lightning above mid range RPM. How/why the Lightning designer thought it unnecessary to give a normal retard curve is beyond me, but it's in my favor. If you will look at motorcycle ignition curves you will see that the final timing is always close to 10 degrees BTDC at peak RPM and that the downward slope towards that starts early. Take a look at these graphs to see what I'm talking about:
View attachment 52275
The RM curve to watch is the full throttle one since motorized engines at peak RPM are always at full throttle. The RM peaks at around 9200RPM, typical of 250cc motocrossers.
View attachment 52273
View attachment 52274
In conclusion it looks like the Lightning is too retarded at around 3000RPM, which limits power, and too advanced at high RPM, very similar to the standard CDI, which limits power and rpm and causes vibration. Now I see why he never has made available the timing curve.
I'm sure now Huffy will huff and puff like a big bad wolf and say his makes more power, blah blah blah without giving a good technical explanation of why. Soon JNMotors will have dyno results for a modified engine using both CDIs so we can all see the actual power difference. But apart from power there are two other things to consider; vibration and reliability. More retarded timing at high RPM lessens the vibration from these engines. Why? It counters the imbalance. The flywheels have too little metal removed at the counter-balance holes. Reliability is improved by retarding high RPM ignition because having the ignition happen too early means the peak combustion pressure will be happening more around top dead center instead of around 10-15 degrees after top dead center. That early peak means much more pressure on the bearings which wears them out early.
Click to expand...

This is interesting. You are saying jaguar ignitions are the best but I have never seen one.
Where can you get a jaguar ignition for an 80cc from in Australia?
 
I'm the originator of good alternative ignition systems for these engines but I no longer have distributors since I made too little money that way.
I have a couple in stock if you want to buy one from me. Click on my signature link and go to the CDI page that tells how to buy it.
 
We've only had single inquiry since we stopped selling CDI's. Just not a big mover. I thought they worked well, but people want cheap and if it works, more or less, no need to buy another ignition system in their minds. Both my Lightning and Jag still work fine, but I ride electric 95% of the time now.
 
for these engines, unless they are tuned to a tee, are not very picky about timing.
But anyone who has raised their compression definitely needs an aftermarket CDI with retarded timing.
I wish I could afford electric. :-(
 

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