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I have found a Daiichi Alloy Sport Rims Catalogue here. As we all know, Daiichi Alloy is made from Thailand and that is a good reason to buy it. This is due to the fact that Thais really like to modified their bike to the extreme. Also, it is cheaper than to buy Enkei rims. Even though it is cheap, it is proven to be safe and reliable as it is used in races in Thailand.

Enjoy the sport rims model for 125Z, EX-5, RX-Z and many more.


RX-Z CDI Unit Assy

Capacitor discharge ignition (CDI) or thyristor ignition is a type of automotive electronic ignition system which is widely used in motorcycles, lawn mowers, chain saws, small engines, Turbine powered aircraft, and some cars. It was originally developed to overcome the long charging times associated with high inductance coils used in inductive ignition systems, making the ignition system more suitable for high engine speeds (for small engines, racing engines and rotary piston engines). Capacitor discharge ignition uses capacitor discharge current output to fire the spark plugs.

History

The history of capacitor discharge ignition system can be traced back to the 1950s together with the development of other electronic ignition systems. The first commercial motorcycle using the CDI system was manufactured by Kawasaki.

By the end of 1960s, the US government made new laws enforcing strict emission standards. As a result, more and more electronic ignition systems were developed, and starting from 1970s all smaller engines installed CDI system to replace the contact point system, including Honda Cub which began to use AC-CDI system.

The basic principle

Most ignition systems used in cars are inductive ignition systems, which are solely relying on the electric inductance at the coil to produce high-voltage electricity to the spark plugs as the magnetic field breaks down when the current to the primary coil winding is disconnected (disruptive discharge). In a CDI system, a charging circuit charges a high voltage capacitor, and during the ignition point the system stops charging the capacitor, allowing the capacitor to discharge its output to the ignition coil before reaching the spark plug.

A typical CDI module consists of a small transformer, a charging circuit, a triggering circuit and a main capacitor. First, the system voltage is raised up to 400-600 V by a transformer inside the CDI module. Then, the electric current flows to the charging circuit and charges the capacitor. The rectifier inside the charging circuit prevents capacitor discharge before the ignition point. When the triggering circuit receives triggering signals, the triggering circuit stops the operation of the charging circuit, allowing the capacitor to discharge its output rapidly to the low inductance ignition coil, which increase the 400-600 V capacitor discharge to up to 40 kV at the secondary winding at the spark plug. When there’s no triggering signal, the charging circuit is re-connected to charge back the capacitor.

The amount of energy the CDI system can store for the generation of a spark is dependent on the voltage and capacitance of the capacitors used, but usually it’s around 50 mJ.

Most CDI modules are generally of two types:

  • AC-CDI – The AC-CDI module obtains its electricity source solely from the alternating current produced by the alternator. The AC-CDI system is the most basic CDI system which is widely used in small engines.

Note that not all small engine ignition systems are CDI. Some older engines, and engines like older Briggs and Stratton use magneto ignition. The entire ignition system, coil and points, are under the magnetized flywheel.

Another sort of ignition system commonly used on small off-road motorcycles in the 1960s and 1970’s was called Energy Transfer. A coil under the flywheel generated a strong DC current pulse as the flywheel magnet moved over it. This DC current flowed through a wire to an ignition coil mounted outside of the engine. The points sometimes were under the flywheel for two-stroke engines, and commonly on the camshaft for four-stroke engines. This system worked like all Kettering (points/coil) ignition systems… the opening points trigger the collapse of the magnetic field in the ignition coil, producing a high voltage pulse which flows through the spark plug wire to the spark plug.

If the engine was rotated while examining the wave-form output of the coil with an oscilloscope, it would appear to be AC. But you must consider that since the charge-time of the coil corresponds to much less than a full revoltion of the crank, the coil really ‘sees’ only DC current for charging the external ignition coil.

There exist some electronic ignition systems that are not CDI. Some systems use a transistor to switch the charging current to the coil off and on at the appropriate times. This eliminated the problem of burned and worn points, and provided a hotter spark because of the faster voltage rise and collapse time in the ignition coil.

  • DC-CDI – The DC-CDI module is powered by the battery, and therefore an additional DC/AC inverter circuit is included in the CDI module to raise the 12 V DC to 400-600 V DC, making the CDI module slightly larger. However, vehicles that use DC-CDI systems have more precise ignition timing and the engine can be started more easily when cold.

Advantages and Disadvantages of CDI

A CDI system has a short charging time, a fast voltage rise (between 3 ~ 10 kV/μs) compared to typical inductive systems (300 ~ 500 V/μs) and a short spark duration limited to about 50-80 µs. The fast voltage rise makes CDI systems insensitive to shunt resistance, but the limited spark duration can for some applications be too short to provide reliable ignition. The insensitivity to shunt resistance and the ability to fire multiple sparks can provide improved cold starting ability.

Since the CDI system only provides a short spark, it’s also possible to combine this ignition system with ionization measurement. This is done by connecting a low voltage (about 80 V) to the spark plug, except when fired. The current flow over the spark plug can then be used to calculate the temperature and pressure inside the cylinder.

References

This article is quoted from Wikipedia.

Coming soon, how racing cdi unit can really boost up the performance of the engine. Stay tuned!

RX-Z 100S

RX-Z started its production in 1980’s. At that time there are two version of RX-Z, namely RX-Z 100 and RX-Z 135. RX-Z 100 was specifically designed to fit the market in Mexico only, therefore we didn’t have it here in Malaysia. RX-S 100 and RX-S 115 was the common bike that we see before the introduction of the legendary RX-Z 135.

RX-Z 135 was introduced at that time with 5-speed transmission, box speedometer and straight exhaust pipe without the resonance chamber. Even though the design is created almost 27 years back, but it still relevant in today’s motorcycle environment. The design is still fresh and amazing. Given the power of 135 cc with 2-stroke class engine makes it a very intimidating bike. In year 1985, people who buys the RX-Z 135 is said to have a fun lifestyles, macho and having daring personality. RX-Z 135 design also is very futuristic compared to the bike such as Honda Raider, Suzuki Katana, X7 and Kawasaki GTO. RX-Z 135 is known for their awesome power can be harnessed easily just by a little modification. The most popular and cheapest modification with great performance boost is done by changing the exhaust pipe to a racing exhaust pipe. A good racing pipe can add up to 3 ps. This can be achieved if the exhaust pipe have a good resonance chamber that can works likes a mini turbo without the turbine. But, even in standard condition, the bike can go up to 150 km/h and that is higher than the highway speed limit here in Malaysia (110 km/h). Most of the RX-Z 135 owner here have modified their bike to go up to 200++ km/h and they used it for daily commute and mind you, it is not for racing. Speed is one of the reason why RX-Z 135 is very popular because we need it to overtake big lorries and heavy trucks during the commute using highway or specifically in PLUS highway here in Malaysia.

In 1990, Yamaha makes a little upgrade to the bike by adding one more gear to the transmission that makes the bike 6-speeder. The design of the exhaust pipe has been updated by equipping it with a new design that have resonance chamber and muffler. This design have increased the power of the bike to 21 ps. Still at this period of time, there are no bike manufactured by other company that beat RX-Z. In fact, there IS no bike by other manufacturer that has been build to be in the same category as RX-Z 135. Most manufacturer like to focus their bike to 150 cc segment. This is true when we look at Suzuki Gamma 150 cc, Honda NSR 150RR and Kawasaki KIPS 150, but here Yamaha also its own weapon that is TZM 150.

2000 has been the year RX-Z get a new cloth. RX-Z has been refreshed with new head and tail design. The new head gets a new smaller headlight. The turn signal has been integrated to the cowling, thus making the bike looks cleaner and more meaner. Tail light has been borrowed from 125Z, but it is okay since the tail light is also nice and clean. But. I prefer for Yamaha to make an original tail light design specifically for RX-Z 135. Clutch has also been upgraded by Yamaha making it is easier to switch gears and better handling for low speed travelling.

Even with lots of reason to be popular, RX-Z is not a bike without flaw. The greatest flaw that I can think of is, the position of the carburetor and the way it is assembled. Since the carburetor is only hold up by 2 connecting rubber, it is very easy to take the carburetor off. And this give way to thief to take it easily. Even if the thief won’t take the carburetor off, they can still steal the petrol from the RX-Z tank since the fuel line is exposed at the left side of the carburetor. I have heard a lot of complain about this from my friends and also from other RX-Z owners.

2008 is a year we all wait for Yamaha to unveil new RX-Z 135 design or at least stripe change.

Here’s the year and code name model change that RX-Z 135 have gone through:

1st model:
1985/87 – 2UX

2nd model:
1989 – 3UK1

3rd model:
1993 – 3UK3

4th model:
1995 – 3RSA

5th model:
1996/97 – 3RSB

6th model:
2000 – 3XL3

7th model:
2002 – 5PV1

8th model:
2005 – 5PV2

9th model:
2008- ??? (not yet introduced)
What is expected in 2008/09 RX-Z model:
Rear mono-shock suspension
Rear disc brake
Inverted front telescopic fork
Double piston front brake caliper
New stripe and design
New & original sports rim equipped

but, you should know that Malaysia already have stopped the introduction of new 2-stroke bike starting the year 2006. So, there are no more new RX-Z model. We will only stick to 5PV2 for the rest of the time.

Long Live RX-Z!

CDI is known to give spark to the running engine, whether it is 2-stroke or 4-stroke. Inside a standard CDI circuit, there is a circuit breaker or rev-limiter or cut-off switch which limit the revolution of the engine. How does it work? Read on the article taken from Wikipedia. This article is about electrical circuit breaker but it can be used to relate to rev-limiter or cut-off switch in engines. In fact, we can’t get away from electrical system when we are discussing about engines.

A device to open or close an electric power circuit either during normal power system operation or during abnormal conditions. A circuit breaker serves in the course of normal system operation to energize or deenergize loads. During abnormal conditions, when excessive current develops, a circuit breaker opens to protect equipment and surroundings from possible damage due to excess current. These abnormal currents are usually the result of short circuits created by lightning, accidents, deterioration of equipment, or sustained overloads.

Formerly, all circuit breakers were electromechanical devices. In these breakers a mechanism operates one or more pairs of contacts to make or break the circuit. The mechanism is powered either electromagnetically, pneumatically, or hydraulically. The contacts are located in a part termed the interrupter. When the contacts are parted, opening the metallic conductive circuit, an electric arc is created between the contacts. This arc is a high-temperature ionized gas with an electrical conductivity comparable to graphite. Thus the current continues to flow through the arc. The function of the interrupter is to extinguish the arc, completing circuit-breaking action.

In oil circuit breakers, the arc is drawn in oil. The intense heat of the arc decomposes the oil, generating high pressure that produces a fluid flow through the arc to carry energy away. At transmission voltages below 345 kV, oil breakers used to be popular. They are increasingly losing ground to gas-blast circuit breakers such as air-blast breakers and SF6 circuit breakers.

In air-blast circuit breakers, air is compressed to high pressures. When the contacts part, a blast valve is opened to discharge the high-pressure air to ambient, thus creating a very-high-velocity flow near the arc to dissipate the energy. In SF6 circuit breakers, the same principle is employed, with SF6 as the medium instead of air. In the “puffer” SF6 breaker, the motion of the contacts compresses the gas and forces it to flow through an orifice into the neighborhood of the arc. Both types of SF6 breakers have been developed for ehv (extra high voltage) transmission systems.

Two other types of circuit breakers have been developed. The vacuum breaker, another electromechanical device, uses the rapid dielectric recovery and high dielectric strength of vacuum. A pair of contacts is hermetically sealed in a vacuum envelope. Actuating motion is transmitted through bellows to the movable contact. When the contacts are parted, an arc is produced and supported by metallic vapor boiled from the electrodes. Vapor particles expand into the vacuum and condense on solid surfaces. At a natural current zero the vapor particles disappear, and the arc is extinguished. Vacuum breakers of up to 242 kV have been built.

The other type of breaker uses a thyristor, a semiconductor device which in the off state prevents current from flowing but which can be turned on with a small electric current through a third electrode, the gate. At the natural current zero, conduction ceases, as it does in arc interrupters. This type of breaker does not require a mechanism. Semiconductor breakers have been built to carry continuous currents up to 10,000 A.

The sport rim here is branded Daiichi Alloy made from Thailand. It is very nice and eye-catching.

The exhaust pipe here is TENCUT Racing Pipe made from Philippine. For me, I prefer the exhaust from YY Pang and AHM since it is already tested and used in Malaysian Cub Prix Championship. But I don’t know if the TENCUT pipe is used in racing in Philippine.
Yamaha LC135 or Sniper in Bermuda

Yamaha LC135 is also known as Sniper in certain country such as Bermuda. The bike is not much different with what we have here in Malaysia. The rear brake is drum. The front brake is still one piston caliper even though the bike is equipped with manual clutch [in Malaysia the front brake is two-piston caliper for manual clutch version]. One thing that amazes me is the rims. I wonder what brand and model of rim it is. The exhaust has been already modified to a new one.

Different sticker design for Yamaha LC135

The other differences that we can spot is the design of the sticker, where it is written Sniper on the side fender. This bike belongs to Stephen in Bermuda.

Thanks Stephen for the picture!

Arkib

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