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Last Updated: September 15, 2014

Motorcycle Racing CDI Repair

Motorcycle ignition are subjected to failure due to many reasons. Even those aftermarket racing cdi are vulnerable to failure. In this article, a famous well known small motorcycle ignition controller in asia got burned by a user by unspecified condition and so handed over to me for inspection internally. It has no activity whatsoever when plugged to a Yamaha Mio scooter, External view of the casing told me there is one small hole with black mark on it indicating that this cdi got a burned component inside and probably the cause is still unknown after i have not open the entire ignition controller and so let us begin the tear down for further analysis.

Same as to those CDI i opened before, need to be very careful not to damage the components inside. The cover will be wasted part of this operation. The ignition controller is heavily coated with rubber epoxy resin, but can easily be stripped off by a piece of pointed wooden material.

Carefully begin the sides first to see the edge of the board. In the photo, i stripped the area of the burnt component to see that component, with the orientation of the parts installed, i knew it has something to do with the High Voltage generator circuit. The part number is totally erased by the burned component. So i need to dig deeper.

Continuing the process of exposing the board as follows. Exposing first the bottom view of the board will make it easier to find where tall components are located and also exposed the area of damaged.

There are also damaged copper foil, indicating not only one part is defective. Sign of too many problems the cdi encountered from the user.

After removing the entire coating of the bottom view of the board, just continue the removal now of the component side with many PATIENCE at hand.

And here is the partial section of that top area of the board. It took hours of removing the stubborn rubber coating. We all know the reason of those coatings before, it protects the entire board from moisture, vibration, dirt and other nature elements that may limit the life of the CDI during operation.

Exposing the board further, Have to desolder some components due to spaces of each part, nearly break a damn 1/8th watts resistor. The silk screen has a marking of component so removing parts and writing down every value of the component is critical from here. And that's the way it should when repairing such item, for once a part gets damaged and value is no longer visible, it will be a waste of time figuring out that UNKNOWN part without any schematic diagram in hand.

Nearing to the teardown,

Let us take a closer look at the damage component. Tracing the entire board and drawing the schematic gives me that the burnt component with a silk screen suffix of S1 made me think it is a Thyristor (SCR) that switches the capacitor to discharge the energy to the ignition coil. a major part of the cdi. I suspect that the output of this cdi got shorted with the igntion coil.

With some part now desolder on the board to thoroughly clean the cdi, Component testing made it easier to find other that failed. Overall it has four components that needed to be replaced to make it working again. As of this time, I am gathering the components needed for it to run again, will do some bench testing using pulse simulator. As far as i am concern, with the look of those failed parts of this ignition controller,

There are many primary reason why it ended this way

1. Overvoltage of the supply
2. Temporary short at the ignition coil area. (output of the CDI to the ignition coil)

3. Wrong wiring connection
4. The least is factory defect...(found some solder residue that may causes the short path of each component in the high voltage section of this cdi)

Part II of this repair will be compose of the bench testing and actual video of it when back to life.


aneka eksperimen said...

BRT (bintang racing team) cdi made from indonesian, beware of the fake BRT CDI release in malaysian.
but you have there is the original BRT.

Nathaniel Berdan said...

yes this is an original BRT..from the MCU can tell it is made by philips semicon NXP, there are many imitation of cannot tell exactly from the outside. Thanks for reminding them.

Santana Karlos said...

Motorcycle parts are never one-size-fits-all and knowing the type of your motorcycle is the first step to get the right parts for your bike.
best motorcycle brands

John said...

Sir about the new racing cdi?is it ac or dc. I have stripped it and i dont know the parts. Pls help

John said...

Heres the pic..

Nathaniel Berdan said...


saw the photo, and the looks of it,I think i not a racing cdi, and it is an AC one for there is no on board DC-DC converter that characterize the DC-CDI from an AC one.

If they tell you that it is indeed a RACING CDI, i tell you it is not.

John said...

Thank u so much master at master tanong q lang kasi may nakita akong 3 wire na diy cdi sa mcp,plano ko sanang gumawa kasi ke100 yung motor q at nang iconvert from platino walang trigger coil..paturo naman po panu gumawa ng trigger or what i need for the 3 wire cdi that dont need trigger/pulser coil..thanks master naka full wave na po ung ke100 ko..thanks to your kindness,i really learned alot.

John said...

Eto po ung pic ng rs na may diy na pulser coil

At eto naman ung 3 wire kdx200 na borrowed from mcp

Nathaniel Berdan said...

since it is an AC-CDI and no advance map like those on a programmable, You can find such that may be applicable to your motorcycle.

Have u seen this one

very simple same as the photo you posted. No tweaks needed, since there are no advance map.

John said...

Thank you so much master..i try this one in the picture you posted and sir can you give me the name and exact numbers needed for that cdi?so that i can buy the parts and assemble it because i dont know the parts in the picture.thank you again sir..

Jason shwartz said...

What a very informative break down on how to repair the circuit board for a racing motorcycle. I'm not a mechanic for motorcycles, but I'm definitely interesting in motorcycles as a whole. Something that was extra interesting is that you mentioned to break apart the paneling that is holding in the board itself.

冠強調 said...

HI I'M ACE , I want buy racing can you for me ?
my line id is ace5899 tks

jo Castillo said...

gud day sir! i do have a racing cdi (brt) for lc 135 and i already striped the rubber coating and all parts are exposed,it is still working but died after couple of minutes,what parts i must replace? is it the capacitor? scr? there are 2 of them (258S8) hope u can help if u want i can send you the picture! tia and GODSPEED!

Nathaniel Berdan said...

Jo Castillo

send me the detailed photo, and i'll see what i can do to pinpoint your problem, normally not all cdi are created equal, each and every cdi differs on the layout and parts used. Use my contact email to send me those photos. Thank you Jo Castillo for visiting this site.

Teddy Benigno said...

Hi master i have problem with my pitsbike cdi 8 steps for raider150
the rpm is not accurate. Sometimes cdi reach the 13k limiter but most of the time its not reach!ng 13k limiter

is there a way that can fix the rpm and make it accurately.?

thanks in advance.

Nathaniel Berdan said...


Hi, sorry for the late reply. I am no familiar with pitsbike cdi. How it provide the tachometer output for your panel. The signal of the STOCK OEM CDI of Raider came inside the MCU, thus it pre condition the pulses generated by the pulser coil then reshape by the MCU and output it inside your raider panel. So this means, the pitsbike do not have the right pulse that is why your tachometer behave erratic. I am no Houdini to provide you information on how to fix it..It is simply not compatible perhaps is your answer.