Headlight Booster

Want more JUICE out of your stock headlight, and do not want to modify your existing wiring. Click to learn more.

HID charging conversion

Are you tired of Battery depletion everytime you uses your newly installed High Intensity Discharge Headlight, Click for solutions.

Fixing OIL drain plug thread

Are you looking for fixing that oil drain plug that went bad and unable to thread that bolt due to loose thread, Here is an easy solution for, CLICK for detais.

Led Light Solution

Wanting to conserve battery power of your motorcycle? Why not change all of your indicator BULBS, such as signal light, tail light and brake light to LED BULBS. Click for more info.


CDI is the heart of your ignition, wanting more power than STOCK but do not want to buy such RACING CDI? You need to know how it work first to understand where to START improving the ignition. Click for more.

Horn Interrupter

Want to have a horn sounds like a machine gun that produces successive sound with only one press of the HORN switch, add spice to that annoying stock horn, CLICK for details.

Reusable OIL filter mod

Paper element OIL filter tends to suffer from clogging, so why not try this filter mod I am using with my small motorcycle for more OIL flow.

Related Posts with Thumbnails

Last Updated: December 05, 2014

CRM250 MD24 CDI no spark problem

CRM250 MD24 is a 2-stroke enduro motorcycle commonly found in UK is very rare to be found in ASIA-Pacific. There are too many model of this actually and the one being the MD24 93" will be discussed. Apparently this post is the conclusion of a dear friend to whom who wrote the problem to me via electronic mail " how good the internet can bring up two people opposite of the globe to communicate and resolve some problem as if we are neighbors"...

The problem was the CDI which is costly refuses to give a  spark. All external component that directs to the ignition controller are all good and thus only the cdi was the suspect.The motorcycle was on a restoration process, and only the ignition was the problem. I had asked his permission to post all the photos here for others who has the same problem that may help you just in case.

Of course, in order for you to do so is stripped all of the epoxy resin that covers the whole black box to expose the board which is very tricky and extra care and more patience is needed. All components must be intact to the board or else it will be much harder to determine what component had failed. Servicing a defective Ignition Controller is difficult and have to isolate each and one block from one another.

Through e-mail, he sent me all the photos needed as shown.

Fig. 1
Figure 1 shows the capacitor with 1.5uf /400 volts

Fig. 2 
Figure 2 shows The MCU and Pulse shaping IC

Fig. 3
Figure 3 is PIN-OUT label of the CDI

Fig. 4
Figure 4 shows Smd components at the solder side of the cdi

Fig. 5
Figure 5  Component Side View of this cdi

Fig. 6
Figure 6  Here, he label the troubleshooting process with voltages reading.

Fig. 7
Figure 7 is the Wiring color code of the cdi

By the way, the CDI of CRM250 MD24 is an AC-CDI type, it has an external high voltage exciter coil that charges the capacitor as the engine is turn. This means that the higher the engine rpm, the higher the voltage can be measured at the charging capacitor.

Moving on finding the culprit of the no spark symptoms of this cdi. Test was done trying to find why it refuses to spark at the tip of the spark plug. Figure 6 shows the voltage reading from turning the engine indicates that there is a voltage at the anode pin of the thyristor. This means that the high voltage of the generator is getting inside, indicating a healthy High voltage generator. One pin of the charging capacitor is connected to that cathode pin of the switching thyristor (SCR), hence there will be voltage, but there will be no vltage at the other pin if your reference is ground, since the charge can only be dumped to the ignition coils primary winding, which act as the load when the SCR is triggered by the MCU. If all is good, the charge will then be dumped causing a momentary magnetic field to that winding and transferred it to the secondary winding in a x10 ratio which is enough to create spark at the tip of the spark plug.

And that is where the problem exist. It does not create any spark. Hence, with the existence of voltage across the capacitor.(by the way to see the voltage is being kept by the capacitor before the dump, put the voltage meter probe across the two pins on the charging capacitor. Voltage will remain there up until the SCR is triggered.)

So before the capacitor, the circuit is generally good. but then the output towards the ignition coil output is not. Generally, If you look at all CDI schematic posted all over the internet, there is still a major component after the pin of the charging capacitor..(did u notice it)

Fig 8
Here is an example, looking at Fig. 8, the RED BOX outline comprises the SCR, the charging capacitor, and a DAMPING DIODE, all cdi must have that diode to protect the SCR and other circuits from getting the HV back after the dump. It is actually connected in parallel to the ignition coil.

That DIODE in regards to the CRM250 MD24 photo,was traced and looking at Fig. 5. designated as D16..

And guess what, It is actually shorted. If that is already shorted then the path of the charging capacitor is nearly directs to ground and no charge will be directed to the ignition coil..

In other words, when the damping diode is already shorted, the charge will no longer flow to the ignition coil, and the system is stopped. Seems odd..that is how it works.

Many will think how the damping diode actually get blown. SIMPLE

if the ignition coil is removed from the circuit and tried to turn the engine without it. The diode will then get the ACTUAL charged of the capacitor and dumps it to ground. It is like shorting the capacitor so that it will discharged the content via the SCR. Eitherway both the SCR and the damping diode will be force to short out. and one of them will get blown, and unfortunately, D16 gets the short condition first seizing the entire circuit from functioning.

So as to state if it is good to disconnect the ignition coil to the output of the cdi when you try to turn the engine..

the answer: NO so always make sure the ignition coil is connected to the cdi. Avoid cranking the engine without any ignition coil connected, Remember, It is easier to fix IGNITION COIL related problems that CDI one, since the later is an external part of the cdi. Internal part of the ignition controller is not exposed and CDI replacement will be costly.

All credit of the photos goes to Mr. David Cooper of UK. Thank you very much, Cheers mate!

Last Updated: December 01, 2014

Motorcycle Front Brake Failure (front brake master)

Have ever been cleaning your entire brake system especially the front brake? Did u ever suspect that it needs an overhaul cleaning to make it  more effective? or Does anyone have a sticking front brake system? This page will tell you that often times which i forgot for many years, the front brake system must be inspected and clean for a more reliable braking system of our motorcycle. So dammed fool of not having it inspected for so many years, that even thought the system still works without cleaning, The pad sticks to the brake rotor causing my front wheel not spinning freely. And so let the tear down begin.

First is to drain all the brake fluid using a hose and an empty plastic bottle of soda. insert first the close wrench number 8 on the brake caliper drain plug bolt and insert the hose to it.

This is to ensure no FLUID will be getting on your precious magwheels and paint. (corrosive substance) and all fluid will get to the plastic bottle. By opening the drain plug bolt, we can now release the brake fluid out from the reservoir by pressing the brake lever on and off until none of the fluid is visible. If you have an extra bottle of DOT-3 brake fluid, you may pour it on the reservoir to push all dirty brake fluid at the hoses and caliper itself so that fresh fluid will be at the hose and brake caliper when putting it all together again. You can also do this procedure later.

 After releasing all fluid inside the reservoir, , it is very difficult to take it out. After minutes of trying to remove it, finally the piston is out. Since this is i think the second time it has been remove in a 10 year span, the fluid already corroded some of it, in lieu with those white powder.

it can be remove from the handle bar and put it on a bench table for rework and general cleaning and inspection. Now the hard part, without the so called
This is a very bad sign, and i think in need of replacement but then this is a DIY page, so i'll still be reusing all of the parts. It will just be clean and remove unwanted debris.

NOTE:  But for readers, it is highly advisable to replace the whole piston assembly with new one. This is to ensure your front brake will not fail. The replacement part is very cheap. You can buy one at every friendly local shop available.

Here is a diagram of every component of the front brake master.

Continuing with the tear down, when the circlip that locks the piston to chamber was remove, the piston can be pulled out from it.

Here we can see the entire piston set of the brake master and photo says it all, YUCKY!!! too much dirt and sediments all over it. I wonder how it still works with that kind of dirt.

close up, that is the view of not totally having a routine check on the entire front brake system of a motorcycle.

Note again to the readers: If you find yourself like this on your motorcycle front braking system, please be advise to change it entirely. Do not re use for fail safe system.

Continuing with the process of my cleaning saga.

With the piston removed from the cylinder, cleaning the master reservoir only needs cloth that is damp with brake fluid. (use only brake fluid, no water, no soap) i used old toohbrush with NYLON bristles on cleaning the entire reservoir. The rest of the picture will tell how bad is this brake master.

and after minutes of cleaning the debris inside the chamber and the reservoir itself..patience makes a lot of difference, ready for assembly and bleeding the entire front braking system on this 125cc motorcycle.

when inserting back the piston to the cylinder. make sure you drop some brake fluid, this will help the primary and secondary cup sealed with the cylinder and glide normally inside of it. Lock the piston with the Circlip double check if is placed inside the groove. then put the dust cap back in its place.

we are now ready for bleeding, the act of removing old fluid inside the hoses and brake caliper.

Pour in fresh brake fluid onto the reservoir, make it full as in full tank. Press and release in cycle the brake lever and see the fluid gets in the hose. When doing this you will see bubbles when you are pressing the lever on and off. this means that the fluid is getting in. Make sure you are topping up when it goes to low level..Continue press and release the lever until it has already a slight tension to it..BLEEDING will come next.

When the lever got any tension on it..(i think you'll be needing someone to press that lever or if u can reach the bolt down while pressing the brake lever, I can call you that you a FANTASTIC man.. :) lol.

1. As you are pressing the brake lever,
2. open the drain plug to release the tension and push the fluid onto the drain plug. When there is no more fluid coming out from the drain hose we fitted onto the drain plug..close it again.and release the lever..press and release again the lever to get another tension and do it again the procedure on bleeding.

Do that procedure until all old fluid came out and that new fluid is coming out already.This is a sign that new fluid is already onto the system and you will have a tension on that front brake lever..

Top the reservoir on the correct level and return the DIAPHRAGM, the set plate and the cover and bolt it..The entire front brake system is done.

Now when you did cleaned the system and the front wheel is not spinning freely. Then the brake caliper is locking and in need of cleaning. The common problem with sticking disc brake is that, it does not return to the idle state when the piston of the caliper pushed the brake pad to the rotor..ROD that connects the caliper to its bracket as shown

This is the job of those number in 10, 15, 9, and 8. It needs to be cleaned.

photo shown next is where to put new grease so that when the caliper push the piston towards the brake pad..the grease will the push back the caliper to the idle state and releases the pad that is in contact with the brake rotor.

Good luck to your cleaning saga!!!..I have speed but without healthy BRAKING system...SPEED KILLS..