My official testing of several different aftermarket CDIs

Venice Motor Bikes

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
I got really sick of all the BS about who's CDI is best.... So I've been testing several different aftermarket CDIs (head to head) for highest spark voltage & total advance degrees at full throttle.

There's a lot more testing to be done but my first results are posted on my VMB/facebook page.

You can click here & see what I have so far. :)

https://www.facebook.com/VeniceMotorBikes
 
This is my home made testing bench... I'm using a coil voltage tester for the CDIs along with a timing light & a fixed degree wheel bolted to the crank to check the spark advance.

I'm also using a digital voltage tester on several different magnetos.



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Below is the largest spark I was able to make... (It came from one particular stock chinese CDI)... It is a whopping 20 full turns!!



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Here's some of the different aftermarket CDIs that I tested with the results...

*edit*>>> The numbers posted are the total advance degrees @ 3000 RPM, & the 'number of turns' is the total outward turns on the coil voltage tester.

All the CDIs that I tested (even the stock Chinese black boxes) have a advance curve of roughly 25-30 degrees.

Most of the stock Chinese boxes maxed out around 5-10 turns, (but one particular Chinese box maxed out at a whopping 20 turns)!!!

My 12v timing light was having a bit of trouble reading the 6v sparks at low RPMs, but I was able to see quick flashes of where the timing curves started.

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Gas Bike just re-named this the 'Super Rocket' CDI


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Gas Bike just re-named this the 'Thunder' CDI.
 
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From my testing, the two GasBike CDIs have the exact same spark power as the HD Lightning, (& also the same retarded timing at 10 degrees BTDC).
These would work best for a really 'hot' running (high revving) engine with a large expansion chamber pipe... (the 'Super Rocket' is a killer deal)!! (^)

The Screaming Roo has the same spark power as the first three, but has the same spark advance as a stock Chinese CDI (20 degrees BTDC).
This would be the best choice for a moderately modified street engine.

The Jaguar CDI has the weakest spark (but still way stronger than most stock CDIs), & the timing is in between the others at 15 degrees.
This is a good choice if you want to change the timing curves for use on different engines.
 
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Yes, thanks for getting into something that there is little hard info on! My question is are these values ultimate advance starting from a lower degree base point or is this a fixed value?, if variable where does the curve begin?
 
Norm,
Are you planning some actual road testing in addition to the bench? Timed/speed trials over a specific distance? It's okay to know voltages and advance curves but I'd be interested in seeing real world results along with them.

Same engine, same bike, same rider, same fuel, tire inflation, etc. Same engine temperature as well as the same weather conditions. Humidity and temperature will play into performance as you well know.

Tom
 
2door said:
Norm,
Are you planning some actual road testing in addition to the bench? Timed/speed trials over a specific distance? It's okay to know voltages and advance curves but I'd be interested in seeing real world results along with them.

Same engine, same bike, same rider, same fuel, tire inflation, etc. Same engine temperature as well as the same weather conditions. Humidity and temperature will play into performance as you well know.

Tom
Click to expand...

Might be worth while to just set up a bench test using the same speedometer on the rear wheel so you don't have other things tainting the results like humidity, temperature, and wind fluctuations
 
YesImLDS said:
Might be worth while to just set up a bench test using the same speedometer on the rear wheel so you don't have other things tainting the results like humidity, temperature, and wind fluctuations
Click to expand...

Still no substitute for real world road testing... there's one important factor missing from bench testing.... engine load. It needs to be able to perform under load in equal conditions by making each run at a specific distance then check the speed or time it takes to get from point a to point b then the test needs to be done going this distance then on the return so you record both directions then average the results to compensate for variables of unlevel road, wind, etc... the temperature isn't a huge factor and wont change a whole lot between runs enough to make a difference... unless a cold front is on its way... humidity can also remain the same long enough to run several tests.
several units can be pres installed on a single bracket and swappdd out either by switches to select which unit will be active or unplugging one andnplugging in the next so all the runs can be done in a very short timeframe like under an hour to test 5 or 6 units on a 1/2 mile to 1 mile out and back run.
the quickest way to switch which unit is active would be by wiring them all to a common plug and using either a selector rotary switch or a switch on each unit and turn off everyone except the one intended for each run, then its just a flip of the switch and the next cdi is active and all others are inactive. A row of toggle switches or a single rotary selector would make switching units take just a matter of seconds, and with a rotary selector you could switch from onento the next without even shutting off the engine.
 
brnotI have tried a few different cdi's an wasted a lot of $. The last one was recommended by a friend.was the supercharged cdi. Well it would not run my bike it just back fired.so i tried it on my other 2.same results. So i tried my friends an it would drop at 7k an the bike tested on was cr machines top motor so i no what works an don't far as cdi's. finally i tried the lightning and to my relief it worked excellent an the lightning did exactly as advertised.i have 2 other bikes an bought one for them an they perform very well also.personally i would recommend the lightning to anyone.brnot
 
I've been a member of this (& other) forums for many years, & over the years, we've seen many shifty vendors posting here using fake names to give fake testimonials slandering other vendors products just to sell more of their own parts!

So Roadrash, you'll have to forgive me when I say that I'm highly suspicious of a newbee member who's only been here 1 month & his only 7 posts on this entire forum are praising CR Machine & HD Lightning (who are known shifty business partners) & slandering their competitions products.

I have nothing to gain, & I firmly stand behind my test results of these other CDIs being equal to the HDL.
I'll be doing even more detailed testing (including actual riding tests) & posting the results (good or bad) here.
 
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Really Neil?? You're a pretty good detective yourself when it comes to these kinds of things...

The 'newbee' doesn't seem at all suspicious to you??
 
I think Fred can get a little full of himself at times, but I believe he sells a good product that he makes himself. I haven't had any problems with Huffy Davidson either, but like Fred I think they can be full of themselves. It's pride, but when it comes to there products as long as they do what they say they do I won't complain. It's when people make carbon copies of others products and sell them as there own when it's crossing the line. Talking down someone else's products is just something that has sadly became the norm when it comes to advertising. Look around it's everywhere.

You might not think you've done it, but you have yourself on your facebook page when talking about the fred head in comparison to your new head

Venice Motor Bikes said:
I spotted a major problem with the 'Fred' head... If you use a decked cylinder or a stroker crank; the piston will touch the head in the middle of the squish area. (Not good)!!
The new VMB 'Shark' heads have a squish area that is contoured to match the dome of the piston & will allow better clearance & compression.
Click to expand...
 
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Vr been following this site for a while but only recently joined.the cdi got my attention.as this is something i positively have experienced i had to post on it.Fred knows the name procustom.autoworks an i got motor an cdi 3wks apart so take my word as true.i took his advice from end to end an i don't think it can possibly get any better. He is the one who out the cdi on me.I've found him to be straight up when it comes to this stuff even if its Not his product.
 
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