My official testing of several different aftermarket CDIs

I don't wan't to sound uneducated about TDC and spark but if the engine fires before TDC by any percentage one the fuel is not fully compressed two the engine will without any doubt fail much earlier than id would firing a zero degrees or precise TDC. Where is the increase of power by firing a mixture before it completely compressed? I'm not an engineer but if I had to rely on the basis my engine would fire at top dead or not at all if it would be so pleased to make sense of doing for me..
 
True YesImLDS... But I supported my claim with actual evidence.
My biggest gripes with Fred & Dan over all these years is that they've made many claims of their products being far superior to their competitons (& they've always refused the requests to show any testing or proof of it).

I didn't do these tests to bash Dan (or Fred); I did these tests solely because I want the best CDI possible on my new race bike, & there's ZERO information anywhere about any of them!

If I find that the HDL (or any other CDI) is truely even just a hair better than the rest?, you'll read about it in my future posts & you'll see it on my race bike next Saturday! ;)
 
Really Im not knowledge in that enough to say. What i am saying is i see by my T.I tach an feel the difference.this is how i determine my opinion.on my other bikes its Not as noticeable but on 1 like i said it will let you no. An with me all advice is welcome.it only makes me faster.
 
BOYGOFAST said:
I don't wan't to sound uneducated about TDC and spark but if the engine fires before TDC by any percentage one the fuel is not fully compressed two the engine will without any doubt fail much earlier than id would firing a zero degrees or precise TDC. Where is the increase of power by firing a mixture before it completely compressed? I'm not an engineer but if I had to rely on the basis my engine would fire at top dead or not at all if it would be so pleased to make sense of doing for me..
Click to expand...

Ignitions needing to fire before top dead center is very common... (the faster the engine goes, the earlier you need to 'light the match' to make the boom. (But lighting it too soon will kill the engine). ;)
 
Venice Motor Bikes said:
Ignitions needing to fire before top dead center is very common... (the faster the engine goes, the earlier you need to 'light the match' to make the boom. (But lighting it too soon will kill the engine). ;)
Click to expand...

Exactly! Because in most cases you have to pre-ignite due to the fact that by the time the explosion reaches the piston itself it'll then be at or just after TDC.
 
I guess as in life it all comes down to the timing lol. There is so much different info an opinion out there it would be nice to have a proven tested answer for any question about these bike.i get lost after a certain point on transfers n timing but have had some good combo come out of trials an error
 
OK I will ask my question again. Are these fixed values or is there a variable curve? If variable where does it began
 
cannonball2 said:
OK I will ask my question again. Are these fixed values or is there a variable curve? If variable where does it began
Click to expand...

The numbers on the cards are where each CDI maxed out at around 3000 RPM... All the CDIs (even stock) has a advance curve of roughly 30 degrees.

After the big race this weekend, I'll have time to do more testing.
I'm going to look for a better timimg wheel & mount it to a running engine & post the results; (both standing still & actual riding results).
 
Thanks for the clarifications! I run a stock CDI and a Jaguar. There is not a lot of seat of the pants difference. I prefer external coil the Jag uses. Its the same as many small engines use and higher output versions are available and cheap.

Using your test results it seems maybe the initial timing is a bit advanced hence the improvement of the lower end from retarding rotor position a few degrees. This probably doesn't matter for you Hi-Perf guys since yall don't stay there long, but the runability of a stocker kinda sucks if you are poking along trails or something.

If you remember how most two stroke outboards worked the timing plate moved many degrees advancing both timing and speed before the throttle ever began opening. The retarded timing at low rpms allowed good slow speed operation.

Anyway thanks for taking the time and effort to put forth you findings, something no one seems to want to do. I did see Jag had a vid of his CDI advancing, but at least to my knowledge he never laid out the values of the units curve, something that is very important for tuning.
 
I've been running my hd lightining for several months now with out any issues. Great product. I would recommend it to anyone over a cheap knockoff! But that my opinion happy motobiking!!
 
I just did several hours of testing all the CDIs in my race bike by blasting it a couple of miles on each one... I'm choosing the Gas Bike 'Super Charge' CDI for the race on Saturday.

Many of them were very close in performance, but this one was just a hair faster & ran a few degrees cooler.


I'll be doing more 'official' testing at a later date & posting the actual test results of the new tests.





image-254072225.jpg


This Max speed is with a 40T rear sprocket.
image-4064234363.jpg
 
Last edited:
I really am waiting for the outcome to this. Are u keeping testing time of day an air conditions in the same time frame. Or does it even matter. I would think if one had access to a computer diag. An run the bike while its hooked up. Like computer tuning a import. For info anyways. That would be great
 
I did these tests 'one right after the other' in the heat of the middle of the day.

Ask Fred & Dan to show you their computer testing equipment & their lists they made of air conditions & such ... (because they didn't do any of that either)! ;)
 
Sorry Norm, it's NOT AS GOOD when they burn-out I know of at least 6 of these cheap a$$ units that have burned out as of TODAY 4/15/2015. One came from PISTONBIKES and never fired once. It's like the old saying you get what you pay for. You buy CHEAP CRAP and that's what you got. They've only been out on the market two or three months and 6 FAILURES that only the ones I've heard about . I'm sure there's going to be more. As far as I'm concerned, I still have and I love this part, "ZERO FAILURES OUT THERE" and over 2500 in sevice and it's been over a year and half.
 
Last edited:
I can't personally compare gasbike's supercharged CDI because I haven't tested one out yet, but I suspect that if you tested 10 of them you'd get 9-10 different results. These are a cheap copy of the bottle rocket CDI (in a nicer looking package) - but they are a copy. Gasbike doesn't care about performance. Look through their performance section and tell me that you'd buy anything from them to make your engine run better. This "super-charged" CDI that is running so hot is probably an anomaly because of the cheap China-grade electronics vary so much. You won't get that with a Huffy Davidson CDI. Ever. They are consistent, reliable, and best of all they were designed here in the USA. They are also made here in the USA.

Recommending anyone to "save their money" and buy the cheapy GasBike CDI is slapping every hard working american in the face. Despite the fact, that I'm banking on the consistancy from one unit to another varying greatly I just personally wouldn't support a company that takes american designs to China and has them made similarly for next to nothing.

Just my 2 cents.
Matt
 
I will say i wasted 23$ on that cdi.not to bash but i wasted hard earned money for something that made my 3 bikes back fire an NOT run.Im still sore over this.but now on all 3 of my bikes i have the lightning.an can ask for no better unit an 1 of my bikes is a serious toy.other 2 are not far behind.the lightning takes anything can throw at it.an Im not just saying this couse Im neutral to all.by the way pay for shipping an a dollar an i will send the S charged cdi to whom ever to examine its inside i just ask for a note on what u find in there.if its a squrell feed it an set it free.besides u no a go
od product when the vendor stands behind it promptly not hide behind voicemail or on hold for a hr.
Ok just venting Im good now.
 
You must log in or register to reply here.
Back
Top