The Step By Step Guide To Your CDI Box Test Vespa Lambretta Scooter

Capacitor discharge ignition (CDI) or thyristor ignition is a type of automotive electronic ignition system which is widely used in outboard motors, motorcycles, lawn mowers, chainsaws, 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 discharge ignition (IDI) systems, making the ignition system more suitable for high engine speeds (for small engines, racing engines and rotary engines). The capacitive-discharge ignition uses capacitor discharge current to the coil to fire the spark plugs. The history of the capacitor discharge ignition system can be traced back to the 1890s when it is believed that Nikola Tesla was the first to propose such an ignition system. In U.S. Patent 609,250 first filed February 17, 1897, Tesla writes 'Any suitable moving portion of the apparatus is caused to mechanically control the charging of a condenser and its discharge through a circuit in inductive relation to a secondary circuit leading to the terminals between which the discharge is to occur, so that at the desired intervals the condenser may be discharged through its circuit and induce in the other circuit a current of high potential which produces the desired discharge.' The patent also describes very generally with a drawing, a mechanical means to accomplish its purpose. This was put into practice starting in 1906 on the Ford Model K. The Model K had dual ignition systems, one of which was the Holley-Huff Magneto, or Huff System, manufactured by the Holley Brothers Company. It was designed by Edward S. Huff with US patent #882003 filed July 1, 1905 and assigned to Henry Ford. The system used an engine driven DC generator that charged a capacitor and then discharged the capacitor through the ignition coil primary winding. An excerpt from the 'Motorway' Jan 11 1906, describes its use on Ford six cylinder cars: 'The efficiency of the Ford Magneto is shown by the fact that the instant it is switched in the car will pick up speed and, without changing the position of the ignition control lever, will run at least ten miles an hour faster.' It was the Robert Bosch company which was the pioneer of the first electronic CD ignitions. (Bosch is also responsible for the invention of the high-tension magneto.) During World War Two, Bosch had fitted thyratron (tube type) CD ignitions to some piston engined fighter aircraft. With a CD ignition, an aeroplane engine did not need a warm up period for reliable ignition and so a fighter aircraft could take flight more quickly as a result. This early German system used a rotary DC converter along with fragile tube circuitry, and was not suited to life in a fighter aircraft. Failures occurred within only a few hours. The quest for a reliable electronic means of producing a CD ignition began in earnest during the 1950s. In the mid-1950s, the Engineering Research Institute of the University of Michigan in cooperation with Chrysler Corporation in the United States worked to find a method to produce a viable solution. They were unsuccessful, but did provide much data on the advantages of such a system, should one be built. Namely; a fast voltage rise time to fire fouled or wet spark plugs, high energy throughout the RPM range resulting in better starting, more power and economy, and lower emissions. A few engineers, scientists, and hobbyists had built CD ignitions throughout the 1950s using thyratrons. However, thyratrons were unsuitable for use in automobiles for two reasons. They required a warm-up period which was a nuisance, and were vulnerable to vibration which drastically shortened their lifetime. In an automotive application, the thyratron CD ignition would fail in either weeks or months. The unreliability of those early thyratron CD ignitions made them unsuitable for mass production despite providing short term benefits. One company at least, Tung-Sol (a manufacturer of vacuum tubes) marketed a thyratron CD ignition, model Tung-Sol EI-4 in 1962, but it was expensive. Despite the failings of thyratron CD ignitions, the improved ignition that they gave made them a worthwhile addition for some drivers. For the Wankel powered NSU Spider of 1964, Bosch resurrected its thyratron method for a CD ignition and used this up until at least 1966. It suffered the same reliability problems as the Tung-Sol EI-4. It was the SCR, Silicon-controlled rectifier or thyristor invented in the late 1950s that replaced the troublesome thyratron, and paved the way for a reliable solid-state CD ignition. This was thanks to Bill Gutzwiller and his team at General Electric. The SCR was rugged with an indefinite lifetime, but very prone to unwanted trigger impulses which would turn the SCR 'on'. Unwanted trigger impulses in early attempts at using SCRs for CD ignitions were caused by electrical interference, but the main culprit proved to be 'points bounce'.
#cdi

[@jnvtechelectronicstv2704]

Thanks for sharing your ideas

[@LambrettaRamesh]

You are welcome

[@eduardoquiroga6804]

My friend, your country makes these after market parts for Vespa, how reliable are they? Thank you Ramesh.

[@LambrettaRamesh]

Vespa parts are very reliable but some Lambretta parts are not reliable

[@divyanshurohilla9681]

Is this the new 12volt conversion kit

[@LambrettaRamesh]

Yes yes. If you closely monitor the stator is new but the stator plate is of old Lambretta (Ducati). I removed the stator from the new 12 volts plate and placed it on 6 volts stator plate after placing vespa LT Coil

[@divyanshurohilla9681]

@@LambrettaRamesh the conversion is very much needed nowadays, I wasn't able to find 6volt bulbs that easily

[@divyanshurohilla9681]

Hello Lambretta Ramesh!
Could you help me with my lambretta gp, it is not taking instant pickup with acceleration, there is delay of around 6-8 seconds everytime I accelerate, just changed clutch plates and the Scooter is on points, points were cleaned and adjusted few weeks ago.
I just want to know what may be the possible sources to check

[@LambrettaRamesh]

Actually lot of points are involved. There should not be clutch slipping. No vaccum leaks at carburetor. Timing must be little bit advanced. Wheels must be free of rotation and many more

[@divyanshurohilla9681]

@@LambrettaRamesh I just changed the carb gasket and tyres are freely moving

[@divyanshurohilla9681]

How to check if clutch is slipping, I changed with new plated today

[@LambrettaRamesh]

There should not be any even little bit blow by in cylinder bore

[@LambrettaRamesh]

There you are exactly. You have to modify the clutch including jetting 👍👍