Will It Spark? Capacitors are replaced with ones that have a longer life expectancy and greater reliability. 0000005952 00000 n Dansk The ratio of turns in the secondary winding to the number of turns in the primary winding, is called the turns ratio. In that case, it it best to dismantle the magneto to retrieve it. Lucas KF2 magneto failure - Britbike forum the brush spring is not touching the terminal in the pick-up holder; the connection between the cable and the pick-up is corroded; the screw in the plug cap has gone down the side of the HT cable and not down its centre; Slip-ring If the magneto is fitted with, or about to be fitted with, a Brightspark EasyCap, you can perform some basic checks on the EasyCap. books, learndpapers and patents on and overhauls. downloadable drawings for those of you who The condensers we get now are made in area's that there are no or very poor quality control checks. In a modern installation, the magneto only has a single low tension winding which is connected to an external ignition coil which not only has a low tension winding, but also a secondary winding of many thousands of turns to deliver the high voltage required for the spark plug(s). We always replace the capacitor during a repair as experience has show us that the capacitor tends to be the most unreliable part. It's easy! This disables the magneto to reduce the risk of electric shock and fire. Regrettably, some Acrobat .pdf files might I worked on farm equipment for my last real service job from 2013 thru 2016. If possible, get somebody to help. Under construction, so far showing video Such a system is known as an "energy transfer" ignition system. Rotate the armature and check that the contact-breaker assembly does not foul its housing. In the case of a main-body earth brush, try moistening a cotton bud with petrol, and poke it through the hole for the earth brush to clean the track while rotating the armature, but IMPORTANTLY before doing that temporarily remove or disable the contact breaker to reduce the risk of electric shock and fire. Now that the slip ring has dried off, replace the pick-up(s). wish to make the required puller tool Dansk However, typical signs of magneto problems are, among others: -- Bike hard to start. U.S. agrees to $5 million settlement over police killing of Bijan Also, with the points open, check that there is an open circuit between them; if fitted with a Brightspark EasyCap, it will take a little while for the resistance reading to climb off the scale. LUCAS MAGNETO TROUBLESHOOTING | JRC Engineering, Inc. We also sell our Brightspark range of Magneto Parts Archives - Rex's Speed Shop BTW, Michael, that's a darn clever trick/solution! If you have identified the magneto as the source of your ignition fault send it to us for repair. slip rings and pick-ups for Lucas and BTH We would therefore strongly advise against ever trying to make a magneto strike a spark across a gap of anything in excess of 7.5 mm in fresh air. 0 One of the plug caps should give a reading which is substantially the same as the reading you obtained in the internal HT continuity section. If you do, then replace the pick-up. Pick-up brushes of the highest A really nice one will jump 1/2"or better. With your multimeter set to display resistance and connected to the opposite faces of the circuit board of the EasyCap (and with your fingers touching no more than one side of the circuit), the meter reading should climb up from a low value until it goes off the scale (OL). The older term "high-tension" means "high-voltage".[1]. We specially-selected, top-quality, British-made Are suppressors and resistor sparking plugs OK to use with magnetos? This can mask a fault on these cars as the vehicle will continue to run until the other fails. [3] The capacitor's function is similar to that of a snubber as found in a flyback converter. Don't flame, hate, spam. On more advanced magnetos the cam ring can be rotated by an external linkage to alter the ignition timing. There is no wire hooked up to the cap. insulators; and timing discs. Trademark Office. Many should appreciate. Parts lists and workshop instructions, not As the magnet moves with respect to the coil, the magnetic flux linkage of the coil changes. The magneto gives a good spark when spun by hand or when kicked over with the plugs removed. 85 0 obj<>stream but enjoy doing it, with confidence, relying on the instruments available for immediate use, and a capacitance to satisfactory ignition system 5.5 mm (220 thou) THREE-POINT SPARK GAP. Links to some interesting wish to 'demystify and simplify' wherever we can, so JRC Engineering Inc. 3110 Indian Ave Unit 1E, Perris, CA, 92571. In the type known as a shuttle magneto, the engine rotates a coil of wire between the poles of a magnet. The readings for the two plug caps should now be swapped around. This disables the magneto to reduce the risk of electric shock and fire. LUCAS K1F MAGNETO RUNNING AT 1200 RPM AT THE ARMATURE. A lot of carbon dust on the inside of the pick-up indicates that the brush is too soft, in which case it should be replaced with a brush of the correct grade. Also, many magnetos (especially twin- and multi-cylinder devices) are provided internally with safety gaps, typically of 6.5 to 7.5 mm, and if the magneto cant find an outlet through whatever is or isnt connected to it, it happily sparks the safety gaps instead. Joined: Oct 2009. If your bike runs poorly, backfires at all but idle, stalls out and won't start back when hot, then works again when cool. (Chinese) Rotate the armature until the contact-breaker points are open. Over time the HT leads can degrade and reduce the potential difference at the spark plug. Free access to service and repair Having removed the contact-breaker assembly from the magneto, disassemble it, noting where each part was. A short circuit absorbs all the power, hence no output or spark. Having set the timing with the points opening on one cam lobe, you should check that it is also correct with the points opening on the other cam lobe. Since the beginning of World War I in 1914, magneto-equipped aircraft engines have typically been dual-plugged, whereby each cylinder has two spark plugs, with each plug having a separate magneto system. With the mag on the engine, there is a spark at all 4 plugs . The voltage generated in the primary winding is a product of its velocity through the magnetic field and the strength of that field, so the condition of the magnet is vital for the correct performance of the magneto. Now line up your degree wheel with the pointer at 38*. The points surfaces should be very slightly convex, so dont worry about getting them perfectly flat. To contact injunmort simply click on his name and the forum will display his e-mail address, Helge. After you get your spark strong enough, then worry about cap and rotor. Trouble starting my 1924 Citroen engine. themselves. a separate spring-loaded holder (Lucas) or hidden at the back of the contact breaker plate (BT-H). V-TWINS Magnetos are always a compromise, usually producing a strong spark to one cylinder and a weaker one to the other. With twin- or multi-cylinder magnetos, and some single-cylinder magnetos, the brass is a segment, rather than a complete ring, and you may need to rotate the armature in order to be able to see it. I would also welcome information on some of the things shown in the video such as the handles on the trolley. Franaise At any one time, we reckon to Translations provided by the Google Thanks. There has been requests lately on the board for more tech stuff. When we undertake the renovation of these magnetos, we examine the following:-. Espaol Do not skimp on quality with pick-up brushes. Common Faults on Magnetos demand to 'perfectly functional' or 'as-new' The original coil may be reusable, although it is susceptible to faults - as described in our section: common problems on magnetos. Copyright 2023, Antique Automobile Club of America. dynamos, regulators, alternators and If your magneto does not have an EasyCap but it fitted with a condenser buried in the armature, then it is impossible to check the condition of the condenser, while the armature is assembled, without specialised equipment. These are prone to deterioration and the cause of many ignition faults. The Magneto Guys - Vintage, Veteran, Classic Magneto Repairs The coils are, of course, designed for this pressure but no insulation is perfect. of which is the product of Brightspark Magnetos Ltd's As the points begin to open, point spacing is initially such that the voltage across the primary coil would arc across the points. We recommend using non-resistive (copper) cable and unsuppressed plug caps. Built into the case of the magneto are magnets, permanent magnets. When screwed in the head, however, the plugs make no spark. 0000001184 00000 n If you have an auto-ranging meter, the reading might jump about a bit on the way while it changes scales. I'm working on a Lucas Mag right now for the first time and this is extremely helpful. To help magneto owners look after their magnetos rebuilt amature runs about 85pnds from independent ignition. Wico-XH Magneto Won't Spark | Smokstak Antique Engine Community 0000003086 00000 n If excessively worn, replace the heel (BTH), or the moving-point assembly (Lucas). heavier the better. If sloppy, consider fitting a new moving point (Lucas), bush (BTH), or pivot post. Please note: THEY ARE NOT FOR SALE! detailed guide to maintaining and The contact points which are mounted onto the end of the armature shaft, used to time the breaking of the primary winding current, will become pitted and worn, especially so if the capacitor is faulty. Contact Us - DO NOT EMAIL CAR QUESTIONS. If it is significantly lower, then there is probably a short-circuit in the contact-breaker assembly or in the armature. I would narrow the plug gaps to .020" and see what happens. books. how they work; and to collate as much other magnetos. A short circuit absorbs all the power, hence no output or spark. With an open circuit the device has no CAPACITY to absorb the reaction voltage (back EMF) from the coil, therefore this energy is dissipated across the timing contact which quickly burns away. 0000001015 00000 n Come join the discussion about performance, restorations, modifications, classifieds, troubleshooting, maintenance, and more! When screwed in the head, however, the plugs make no spark. The other plug cap should give a reading that is infinite (OL) or extremely high. 0000001320 00000 n If not provided with a safety gap, there is a risk of expensive damage. "Colonel fair is fair: if I nail Hotlips and punch Hawkeye can I go home too?". That then produces a gap of about 4 mm between the centre electrode and the screw-threaded bit of the plug body. JavaScript is disabled. Values vary considerably depending on the make and model of magneto and who wound it. Some original units are still in service today. Due to the inevitable losses in the system, this oscillation decays fairly rapidly. instructions). 82 0 obj<> endobj commonly found on classic motorcycles. From the basic to the complex - some I also want to wire up the battery better, as I'm just using jumper cables. and just how were you able to find one of those bastards that still worked?!?!?! Take a look -- Tickover, pulling away, and low-speed running erratic. First test is to take the plug caps off the HT leads and position the ends of the HT leads 1/4" away from the casting.