200.00 cdi you pay for a drill hole

just bought a curtus sparks cdi,,i have heard that the trick to making a aftermarket cdi,drilling a hole in a stock one,i ripped the sticker off and saw where they did it,now iam going to return it,screw that i paid 200.00 for them to drill a hole in a cdi,iam going to do this to my own,,,waste of money

[oynot400]

I am not sure how the change the rev limiter on the cdi box. I would be upset too if that is all they did. :grr I only paid $80 for mine.

[NewRider]

How big is the hole? Im assuming they are using the hole as access to make whatever change is necessesary, instead of trying to remove the molded rubber on the underside of the box. I dont know that, but that would be my assumption if they drilled a hole in it.

John

[PsychoDave]

if that is the case we could modify it ourselves......

[NewRider]

Just putting a hole in the plastic isnt going to affect the electronics. There would have to be an internal change of some sort to change the rev limit. That is why I believe it was merely a more convenient way of access than trying to remove that rubber compound on the underside.

John

[wyndzer]

What they do is drill a hole to access the circuit board. They then remove the solder joint that relays the rev limiter.
So you are paying for a new CDI box, plus the knowledge of what solder joint to break. If you break the wrong one, then you buy a CDI.

CDI new=228.29 from Service Honda

[PsychoDave]

thanks for the info......my brother is an electrical engineer.... if i can get a schematic for the CDI......he can modify it.....then i will share all the info..... but first i need the schematic!!!!

[quadfamily]

Good luck finding a schematic for your CDI box Dave! I tried to look for one for my 300EX CDI without luck. If you find it let us know.

if its just a solder joint, why not just mess with it until it gives the desired results, soldering is preety easy, so it couldnt be too hard to repair... you could even wire in a switch if you found the right solder joint, and mount it on the outside of the box or something, i think that would be a neat mod

thats all false,,,,i called "someone" and he told me all they do is take a 1/8th of an ich bit and make a drill hole about 10mm deep into the box...
i ripped the sticker off of mine,found the spot,made a pilot hole on my stock one,made the drill hole,,,put sealer on it,,let it sit for a minute,,,,ripped the sparks one off,put my newly moded one in,,,,and guess what i found IT WORKS THE SAME,RIGHT I DID IT MY SELF,,AND I AM GOING TO RETURN THE ONE I BOUGHT,SCREW THAT ....and it is not recommended to do,why because a stock ex is tuned to run at 8700rpm's peak,,,add 1000rpm's more with the mod,,,and you have yourself a over stressed crank and top end...
but i have a fully modifed engine and it is tuned to run at a higher rpm,,,so be real carefull with those cdi boxes,also the one for the 400ex,,not recommended also,,it has been poven by allen knowles ct racing that it is a close to useless and make the engine harder to start

to reply to this:all you have to do,is drill a hole 10mm down,thats it..no trick to it,they alll try to scare you by saying,well you are going to ruin your cdi box or you dont know what spot to hit,well i just did,a drill and a bit 10mm deep at a certain point on the box,iam going to pull up soemthing,,you guys need to read that proves this

[Dunlap]

Just to set the record straight, I have never told anybody that all they do is drill a hole in the box. I don't modify the boxes myself. A friend of mine who builds his own televisions from scratch does it and he is an electronic wizz. I don't know what he does to it and for the past 14 years several people have tried it themselves and ruined their boxes. If it were easy to do, somebody would have figured it out by now. Please do not misquote me on these forums - this is how misinformation gets out. If you have questions about it, call me directly.

how about a pic showing where to drill this hole.
how did you get the measurement if 10 mm?

i called and spoke with" someone",who doesnt not want everyone to know that it is that easy to do,again they try to scare everybody buy saying you cant do it or you will damage the box,etc...well anyway i will take a pic of it tommorrow and post

can you post measurments from the top and side so i can tell where to drill

[MIKE400EX]

All they're doing by drilling a hole is disabling a circuit. If you don't drill in the exact spot (circuit boards have very small components and circuit paths), you risk disabling the entire CDI >>>>NOT GOOD! I think the important issue here is that for 99% of the readers a high/unlimited rev CDI will ONLY result in over rev damage to your good motor. Very few modded EX's make much usable HP at 9500+ RPM.

[Scott]

I don't want to argue with anyone, but I also don't want to see a bunch of young guys go ruin their CDI boxes and not have the cash to replace them. So I've got a couple questions.

First, please explain to me how drilling a hole in the plastic case affects the electronic circuit inside that case. Granted, I'm not an electrical engineer, but I am an engineer that designs electrical circuits for a living.

Second, please tell me where I can find a dyno chart that shows how I'll gain ANYTHING from another 1000 rpms. Everything I've seen shows the 400 curves flat or dropping off after the factory redline. Only thing I see you getting from more rpms is over-revving.

If anyone can explain these two things to me, then I might be able to understand why someone would want to do this. Right now, this just sounds like a more expensive "amp link." Anyone that was unfortunate enough to buy an amp link will know what I mean. To get an equal performance gain, take the money for the amp link, light it on fire, and throw it out the window.

Just my opinion.

[PsychoDave]

I agree 100%.... It is more fun to be able to do do the CDI myself (my brother really) than buy it..... I dont need a new CDI at all. I think the stock one is fine....and I dont want to risk over-revving for little or no gain. But if I can help someone else....I will. But I wont take responsibility if they blow up their machine by over-revving.... Thanks for the input Scott...

P.S.... this is my opinion too:D

[Dunlap]

I am not trying to scare anyone into not modifying their box. I am warning them that to my knowledge no one has done it successfully. If you have successfully eliminated your rev limiter completely by drilling it more power to you! I am all for free information that gives good results. That's why I tell people to pull the choke out of the back of their 400EX carbs before buying a bigger one. It's simple and it doesn't cost them anything. I am not here trying to sell anybody anything - I have too much business as it is.

[NJ300ex]

Dannydone has a 300ex. It does make alot of its useable power after the stock rev limiter kicks in unlike the 400ex.


Also dannydone, I was looking through my old dirtwheels and I think you were in the parting shots section. Was that you or am I imagining things.

yea i have a 300ex too, can i can feel a strong pull but i always bang the limiter.