Franaise Translations provided by the Google Translate service. . Also, some pattern contact-breaker assemblies are too large at the fat end and need to be filed or ground to size. how they work; and to collate as much other commonly found on classic motorcycles. I also want to wire up the battery better, as I'm just using jumper cables. A capacitor is placed across the points which absorbs the energy stored in the leakage inductance of the primary coil, and slows the rise time of the primary winding voltage to allow the points to open fully. You need to confirm that the condenser has failed AND that replacing it will solve the problem. Magneto parts We also sell our Brightspark range of specially-selected, top-quality, British-made slip rings and pick-ups for Lucas and BTH magnetos. 0000003777 00000 n With larger gaps, if the magneto is provided with a safety gap, the spark is more likely to jump there where it cant be seen, so thats a waste of time. A good Wico X series mag will jump at least 3/8" air gap. This expediential degradation may appear to be sudden when the fault occurs. at some of the equipment we use in our workshop for magneto servicing JRC Engineering Inc. 3110 Indian Ave Unit 1E, Perris, CA, 92571. If the timing is not correct on both lobes, the reason could be that: the contact-breaker assembly is wobbly on the end of the armature; the cam or its housing were incorrectly machined (rare); with ring-cam magnetos, the armature and cam are not coaxial due to the outer race of the bearing at the contact-breaker end not being seated properly by its insulator in the cam housing. 0000002567 00000 n Norsk This allows the spring to unwind giving the rotating magnet a rapid rotation and letting the magneto spin at such a speed to produce a spark. The Magneto Guys - Vintage, Veteran, Classic Magneto Repairs Lucas Magnetos We have overhauled and repaired these Lucas magnetos and then returned them to their owners. A really nice one will jump 1/2"or better. This causes the electromagnetic field in the primary coil to collapse rapidly. At atmospheric pressure, the voltage required to strike a spark across the 0.020 (0.5 mm) gap of a sparking plug is far less than the voltage required at the elevated pressure that the plug experiences in the engines cylinder. Ignition - Check Spark strength, Spark timing and . The voltage generated across magneto coils is quite high, in the order of 20,000 volt if no spark plugs are in place. (Japanese) Then measure the resistance between the two points of the contact-breaker. Magneto coils are usually a long time dying. It appears that magnetio does not have in impulse coupling which means the engine must turn over much faster to develop as hot a spark as if there was an impulse. The irony here is that usually these magnetos fail to spark. We are unfortunately not able to offer However, dont make them lop-sided. books. Checked it over and found no spark. Likes: 260. scotland. In the type known as a shuttle magneto, the engine rotates a coil of wire between the poles of a magnet. In the late 1890s, English engineer Frederick Richard Simms and German engineer Robert Bosch developed the first practical high-tension magneto. The plugs all light when loosened, but not when installed. Mechanical - Bearings, insulation, washers and shimming the armature. Translations provided by the Google It uses a magneto and a transformer to make pulses of high voltage for the spark plugs. I was bench testing by tuning the mag slowly by hand, without the impulse coupling attached, so 1/4" is a good distance. Values vary considerably depending on the make and model of magneto and who wound it. However, typical signs of magneto problems are, among others: -- Bike hard to start. If the brass is black, it indicates that the brush(es) are too soft and/or years of neglect. the brass is in the wrong place, as a result of a magneto with a segment-type slip-ring having an incorrect cam fitted or having the wrong direction of slip-ring fitted. If not free to move, ease it. Can you rig up real cables? magnetos and capacitors (for those who wish to As the points begin to open, point spacing is initially such that the voltage across the primary coil would arc across the points. This disables the magneto to reduce the risk of electric shock and fire. I tested the HT wire and spark plug and both are fine. Rotate the armature and check that the contact- breaker spring never touches the cam. 0000005012 00000 n [6], The first car to use magneto ignition was the 1901 German Mercedes 35 hp racing car, followed by various cars produced by Benz, Mors, Turcat-Mery, and Nesseldorf. NEWS FLASH - March 2020 As you will understand, with the Covid-19 pandemic shutting down most normal business, we are not able to despatch orders for the time being. errors in the translations. Check the condition of the HT lead(s) and plug-cap(s) and replace where necessary. The reading should be substantially the same as the reading you obtained in the internal HT continuity section. I can guarantee every British motorcycle powered by a magneto i either not delivering maximum spark and/or is on the verge of failing if the original Lucas capacitor has not been replaced. We will check all the parts of the magneto for faults and will provide a firm quotation for a repair along with a description of the magneto repair required. 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). Over time the HT leads can degrade and reduce the potential difference at the spark plug. read more deeply). Check for wear and replace any worn parts. If it is significantly higher, there is a bad connection or break in the low-tension circuit, in which case the magneto will need a more complete overhaul. 096792012013 - 2020 | Website design by The Net Effect of Sheffield, Website design by The Net Effect of Sheffield. The high voltage will simply arc across the gap. Points and contacts cleaned, and wires tested for continuity. Twin sparks provide two flame fronts within the cylinder, these two flame fronts decreasing the time needed for the fuel charge to burn. Italiana We would recommend having the transformer coil rewound as modern class F or H wires and insulations are superior to the ones used at the time it was originally made and would almost certainly give you another 40 years of good service. Or what else could be causing this? On the Lucas magnetos, the spec is to jump a .200 gap at 200 rpm for the slow speed test. I have tried both Champion and NGK plugs. Wrap some rag around the end of a stick about 1/4 diameter, moisten it with petrol or other cleaning fluid (but not so much that it is dripping), poke it through the pick-up hole in the magneto body, and rotate the armature to clean the slip ring. 0000002847 00000 n There has been requests lately on the board for more tech stuff. information as we can about the electrical equipment Now let the slip ring dry out with the pick-ups still removed. If youre giving your magneto a thorough check over, we suggest you tackle jobs in the order shown. many ignition systems, focusing especially on If you do not obtain readings substantially the same as the reading you obtained in the internal HT continuity section, and if everything else you previously checked is still good, it indicates that the pick-up brush(es) is/are not making good electrical contact with the brass of the slip ring. ZK~!c. If working on your own, holding the end of the HT cable steady 6 mm from the engine is difficult when kicking the starter. Check the state of the tappet and replace if necessary. All An ignition magneto (also called a high-tension magneto) is an older type of ignition system used in spark-ignition engines (such as petrol engines). The Lucas magdyno and magneto units fitted to all AMC machines after 1939 had Nifal magnets which are not demagnetised by removal of the armature. If you have identified the magneto as the source of your ignition fault send it to us for repair. instructions). 5.5 mm (220 thou) THREE-POINT SPARK GAP. We provide 82 0 obj<> endobj A short circuit absorbs all the power, hence no output or spark. Always good to learn how to check lucas parts, one of the weaker parts of a triumph motor.. Classic Cycles inc. 2199 N. Batavia Suite J. I have seen that a lot on FM mags. The spark is fine on this coil, keep in mind the faster you turn a mag, the better the spark. We also have kits for more unusual magnetos, such as the BTH, ML, Magnetos France, Morel, Lucas wader, Lucas KVF, etc., and for cars. I'm thinking the magneto is weak even though it was rebuilt with new condenser.. Posts: 34. If sloppy, consider fitting a new moving point (Lucas), bush (BTH), or pivot post. Tri-Spark Ignitions; Pazon Ignitions; Lucas Rita; AGM Batteries For Classics; Lucas Alternators; Rectifiers & Voltage Control; Dynamo Parts; Magneto Parts; Lucas SR Magneto Spares; HT Coils For Classic Bikes; British Bike Points & Condensers; . If it is several thousand ohms, it indicates that the HT lead is resistive and/or the plug cap is fitted with a suppressor resistor. Take a look at some of the equipment we Thanks. Others have an earth brush between the main body of the magneto and an earth track of the armature. To have the discharge go arc back into the coil itself or the mag housing causes some serious damage. I'll try the 3/16" gap test. To help magneto owners look after their magnetos 0000001015 00000 n These are prone to deterioration and the cause of many ignition faults. i found that is a cheaper, easier way to go than doing it my self with refurbished parts. heavier the better. Click Here to view Lucas face cam (magdyno) parts manual. Nederlandse I did notice a very small spark between the contact breaker points. Lucas vertical magneto in good condition and sparking. part-exchange. that old problem, the deeply-buried condenser She was factory fitted with a Morris Vedette MKII engine which has a lucas rf4 magneto. 0000001320 00000 n Lister D Magneto Lucas RS1 full rebuild but still no spark Coil Fail. The condensers we get now are made in area's that there are no or very poor quality control checks. It uses a magneto and a transformer to make pulses of high voltage for the spark plugs.The older term "high-tension" means "high-voltage".Used on many cars in the early 20th century, ignition magnetos were largely replaced by induction coil . If the magnet is full strength and the spark at the points looks right then I would still say you have a coil problem with some shorted turns or something. 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. Capacitors are replaced with ones that have a longer life expectancy and greater reliability. Housings can sometimes get misshapen, in which case try to rectify that. Still here since 1996 serving BritBike enthusiasts. Lucasworkshopinstructions-magnetosLucasworkshopinstructions-otherstuffLucaspartslistsLucasATDspecificationsBTHinstructions&partslistsM-LBookletsMagntoFrancedocumentationRobertBoschDocumentationAmericanBoschworkshopinstructionsPatentsBooksandlearndpapers, Redesigned contact breaker for ring cam models, SR1, SR2 & SR4 magnetos (workshop 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. In this series of pages, well take you through the main things. "A Community of Antique Engine Enthusiasts." For a better experience, please enable JavaScript in your browser before proceeding. Copyright 2023, Antique Automobile Club of America. Contact Us - DO NOT EMAIL CAR QUESTIONS. This was diagnosed as the cam ring not being properly timed to the magnetic poles. As the size of the combustion chamber determines the time to burn the fuel charge, dual ignition was especially important for the large-bore aircraft engines around World War II where it was necessary to combust the entire fuel mixture in a shorter time than a single plug could provide, in order to build peak cylinder pressure at the rpm desired. If there are any, repeat until the paper comes out clean. Great photos, quality! making your own bearing and slip-ring pullers; Deutsch 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. Trouble starting my 1924 Citroen engine. slip rings and pick-ups for Lucas and BTH "Colonel fair is fair: if I nail Hotlips and punch Hawkeye can I go home too?". If your multimeter can measure capacitance, the reading should be within 10% of: 150 nF (0.15 uF) for the C01, C02, C03, C05 and CU/150 EasyCaps; 220 nF (0.22 uF) for the C06, C07 and CU/220 EasyCaps. It is almost a given that a Lucas armature will require replacement if in the original condition. troubleshooting your magneto. Replace if necessary. With the engine running, place your hand over the pick-up with the same hand also touching the magneto body. 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. I'd need to install it in the chassis or rig up something to do that. The other thing I have noticed is the spark will arc to ground when compression is on the plug if external arcingis the path of least resistance. [5] The hub of the magneto rotates while the drive shaft is held stationary, and the spring tension builds up. only for magnetos, but also classic motorcycle An importance cause of field strength reduction is the removal of the magnet from its normal situation without fitting a keeper, a device designed to maintain the integrity of the magnetic circuit. If it was a typo then you can run it with the cap and rotor off by just holding your wire to the HT terminal and that would eliminate the cap land rotor from the equation. Check the state of the heel of the moving-point assembly. For example: Check as best you can that the brush is actually making contact with the track on which it runs. that more owners can not only maintain their magnetos, At any one time, we reckon to I highly doubt it is excessive unless someone has been grinding the rotor or the cap. If there is a lubricating felt, soak it in oil. In more modern times, insulation materials have improved to the point where constructing self-contained magnetos is relatively easy, but energy transfer systems are still used where the ultimate in reliability is required such as in aviation engines. You can check the latter by removing the pick-up(s), rotating the armature in the proper direction until the points are just opening, and checking that the brass is visible directly underneath the pick-up hole (or one of the pick-up holes) in the magneto body. Brightspark Magnetos is now able to offer a remagnetising service, using our specially-developed remagnetising and measuring equipment to help you restore your magneto to tip-top condition. However, if the reading is more than 7000 ohms, there is probably either a break in the HT winding, or a bad connection between the live end of the HT winding and the slip-ring. Powered by Invision Community. 1. If not provided with a safety gap, there is a risk of expensive damage. Thank you for your patience. 0000013093 00000 n Not sure what came off, but 1930s/40s I would have thought.prefer collection, but would post. Check for any dirty marks on the paper. Sign up for a new account in our community. I know a great starting engine will fire a plug with 3/16" gap when external of a cylinder. Dansk In either case, the magneto needs a more complete overhaul. Having removed the contact-breaker assembly from the magneto, disassemble it, noting where each part was. Put a smear of grease on the surface of the cam that engages its housing. If there is a groove where a lubricating felt should be, but is missing, consider making and fitting a replacement. The magneto is rebuilt by a reputable US shop. The capacitor and the coil together form a resonant circuit which allows the energy to oscillate from the capacitor to the coil and back again. If you have a plug tester available that adds simulated compression pressure (using air pressure) to the end of the exposed plug while firing voltage to it you will see the more pressure the higher kv the plug needs to fire correctly. This Lucas KVF magneto was rebuilt 7,000 miles ago and failed at around 3,000 miles with loss of spark on one cylinder. With a multimeter, check the resistance between the tip of the pick-up brush and the terminal in the plug cap. That then produces a gap of about 4 mm between the centre electrode and the screw-threaded bit of the plug body. Lucas Ga4 Magneto Austin 7, Morris, Riley And Many Others Service Exchan. 2. Main-body Earth Brushes and Bearing Insulators: Some magnetos have an earth brush between the contact-breaker back-plate and the contact breaker housing. Some original units are still in service today. instruments available for immediate use, and a pouvons vous aider soit en franais, soit en Then check that the contact-breaker assembly is not wobbly on the end of the shaft. The engine needed some attention, which it has now received, but I had to take the magneto off. The older term "high-tension" means "high-voltage".[1]. Dansk I did run the rpm up with my lathe to 1,000 rpm & it easily jumped 5/8", so were good there, SMOKSTAK is a Registered Trade Mark in the U.S. A fair amount maintenance and troubleshooting of a magneto can be done with the magneto in situ and without any special tools or equipment other than a multimeter. One or more times per revolution, just as the magnet pole moves away from the coil and the magnetic flux begins to decrease, a cam opens the contact breaker (called "the points" in reference to the two points of a circuit breaker) and interrupts the current. What else could possibly be grounding this? equipment. performance. Gift Article. The gap will widen as the wire ends melt further apart and soon the adjacent turns will be affected so the coil will eventually fail. I have seen several condensers during that time whichwork for the half but will not generate the field collapse andfire the plug . I would definitely try another condenser if it were me. The air gap allows the voltage to build on the rotor until it is high enough to jump the gap thus it actually magnifies it somewhat. This disables the magneto to reduce the risk of electric shock and fire. It should fit properly in only one precise position. With the earth brush(es) now replaced, measure the resistance between the back-plate of the contact breaker assembly and the main body of the magneto. Thoroughly clean the pick-up using a rag moistened with petrol. Blue spark is great but if it can only jump .03" when external of a cylinder with no compression pressureswhen you add the compression and fuel mix it will fall on its face. 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. V-TWINS Magnetos are always a compromise, usually producing a strong spark to one cylinder and a weaker one to the other. Turn the armature in its proper direction of rotation until the contact-breaker points are just starting to open. There are several common faults with magnetos The Capacitor Capacitors, which are short-term storage devices, often fail in older magnetos due to dielectric degradation (short circuit) or conductor breakage (open circuit). If the reading is less than 3000 ohms, it would be unusual, but is indicative of a problem. Built into the case of the magneto are magnets, permanent magnets. It's a 6v system, so the starter turns rather slowly (maybe 80rpm), but I think it should be fast enoughto start. BTH mags utilized condensers made from mica. Feel free to buy the forum staff a coffee or pint or just make a contribution of your choice. If your magneto is loosing spark after a short amount of time running, or is hard to start it is most likely a condenser failure. With the plugs in the engine connect one plug outside like you have been testing it to confirm no spark, If there is spark present I would open the gap of an old spark plug to 3/16" and see if the spark will jump that gap. After a full rebuild my motor started right up, rode for 5 minutes, stopped, no spark. use in our workshop for magneto servicing Alnico, the material most often used to fabricate early magnets has a tendency to lose its induced magnetic field over time due to various causes. From the basic to the complex - some - there's a lot of stuff in our frequently information aggregated from many sources. Measure the resistance with the two probes of your multi-meter shorted together. Check the cam surface. 0000006372 00000 n I got it back, spun it, sparked. Make sure they are there and can move in their holders and give them a good clean. Italiana Ensure that you have the proper gasket fitted. Dual plugs provide both redundancy should a magneto fail, and better engine performance (through enhanced combustion). You are probably loosing amperage through the jumper cables. Place a clean piece of strong paper between the points, and with the points closed pull the paper out. 0000001184 00000 n Replace the cam, ensuring that the notches in it engage as before (e.g. This could be because: the brush isnt projecting far enough to touch the slip ring, so check that as best you can. (Chinese) MochetVelo is it rebuilt? I forgot about this. Replace the main-body earth brush, if applicable. Once the insulation has been broken down once, it often makes it easier for it to be broken down again. Put it on bike, timed, no spark. British motorcycles on e-Bay North America, Powered by UBB.threads PHP Forum Software 7.7.5. A small number of electrons is ever present and over years or decades this flow carves out an ever widening pathway through the insulation. dynamos, regulators, alternators and magnetos available for sale or in Could be bad parts if spark just gets a lot weaker but if spark totally goes away when cap and rotor are installed, be sure the when you install them it does not short out the primary, give the rotor a closer ground to jump to or hold the points open, etc. Our replacement for the condenser (capacitor) in Without suppressor: suppressor: Percentage difference with suppressor: Peak HT voltage to initiate spark: 9600 V: 10600 V at magneto: 10.4 %: 9300 V at spark gap-3.1 %: DC component of HT current immediately after striking spark: 53 mA: 52 mA-1.8 % Do not skimp on quality with pick-up brushes. Please note: THEY ARE NOT FOR SALE! The other plug cap should give a reading that is infinite (OL) or extremely high. Pick-up, HT Lead and Plug-cap 1 rectifiers (and wiring diagrams) of use to all Two beveled teeth on drive gear(which are generally parallel to flat for shaft it fits on) should go to mark on rotor which is under lead out finger. For example, in the Lucas K1F and K2F, the earth brush is located on top inboard of the main mounting flange. Due to the inevitable losses in the system, this oscillation decays fairly rapidly. With a twin, repeat with the other pick-up. With Lucas devices, if it fouls the contact-breaker spring, the contact-breaker assembly will need to be removed and the effective length of the spring increased as necessary. Brightspark Magnetos Ltd disclaims responsibility for any to suit the needs of a customer. By 0000002602 00000 n Rotate the armature until the contact-breaker points are open. Lucas Magneto 1930 - 1940. replace it with an EasyCap. You should not feel any tingles in your hand. Upgrade your membership to Such a system is known as an "energy transfer" ignition system. I was hoping that some of the experts might help me with a magneto problem. If it does not jump 3/16" it probably will not fire a cylinder under compression. In that case, it it best to dismantle the magneto to retrieve it. Our preferred gap for spark testing in fresh air is 6 mm.

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