10% power gain by motorcycle CDI/coil

I thought that replacing the standard CDI would help some but not this much! I perfected my design and got almost 10% power gain. I used to climb one street at 20.5mph but now I do so at 22.5mph. That's a gain of 9.75%. But there's science to back up this idea. (see "Devices to improve the performance of a conventional two-stroke spark ignition engine") Since 2.5% more power is derived from each 33% increase in spark power then a 10% increase of power means the new CDI has 133% more spark power! Not so amazing really considering how small the ignition coil must be to fit inside the standard CDI/coil combo. To read more about this all go to my page about Ignition Timing Changes
The CDI is now available for purchase also.

 

[proctor-nashua]

okay you got me i'll still buy one sameday

 

[Dave C]

Your link to the CR ignition spark coil is perfect. Brand new coil for $16.95 with shipping, that's cheap. And new...and cheap(i think i said that)

I looked on eBay...some of those people must think there's gold in them thar coils...$70 for a beat up old coil? And $15 for shipping? Give me a break

 

[Dave C]

Part ordered

 

[Deleted member 12676]

Cool. What puzzles me is how few people realize the importance of the ignition system. What comes on the HT is something that only advances the ignition with rpm's, without retarding it back at high rpm's. That's for a 4 stroke, not a two stroke. No wonder these things vibrate and get too hot. The Chinese factory bought these incorrect CDI/coils for the weak spark and overly advanced ignition at high revs so it would limit the power and be within legal regulations for more countrys. So what do the owners want, be perfectly legal or have a motored-bike that has some power? I myself want to squeeze every ounce of available power from these engines. I don't ever want to pedal except starting from a stop.

 

[Dave C]

I looked over the design and it left me wondering if where you can change the timing, can that be done with an externally adjustable pot? Mainly as a tuning device although I can see racers buying this system to change timing during a race.

 

[Deleted member 12676]

Of course an adjustment pot could be external but for simplicity and reliability sake I make them with two jumpers on the circuit board so you can set it and leave it without risk of external wires breaking due to vibration.

 

[Dave C]

Heh, I was just talking about sticking a knob or two out the side of the box, not remotely mounting it The box can be mounted anywhere on the bike so putting it somewhere where access is easy was my idea. And the variance given by the pots can be adjusted so they do not affect too much of a range in degrees of timeing.:helmet:

 

[Deleted member 12676]

OK but the input resistance range is 14 to 16 ohms. Hard to find a pot to suite. What I could do for those that ask, is use a switch that they can reach while riding. If you insist. I found the setting best for my bike and have no need to adjust it while riding. An external switch would be subject to long term damage by vibration and would allow water in. Not good no matter how you slice it. Believe me, I've already thought these things thru.

 

[SlugMan]

I just ordered mine the other day!! After reading and learning how these China ignition systems advance in a four stroke fasion, it only made since. It will spin the motor faster, run smoother/cooler, and has 4 timing settings. It ended up being a $60 dollar upgrade ( KX80coil $20, adjustable CDI $40) I'll keep ya posted, once I install it on my Grubee 66cc Skyhawk... I also ordered a high compression head from Rock Solid Engine today to compliment the ignition system. Higher compression needs a stronger spark. I'll let you know how mine works out.

 

[DuctTapedGoat]

Looks nice and all, but 75 bucks is a lot of money for what it really is. I'd pay 5 bucks to see the schematics, and go buy everything at my local component shop and do everything myself. Way too jacked up a price for a simple circuit.