Check the state of the points surfaces. Measure the resistance with the two probes of your multi-meter shorted together. I also needed a new coil for it which I installed, cleaned the mag up and replaced any bits it needed. DIY Magneto Maintenance and Troubleshooting Twirl the armature. or Franaise Translations provided by the Google Translate service. Translations provided by the Google The other plug cap should give a reading that is infinite (OL) or extremely high. They were used in the village forge in Cullworth (northaptonshire). The permanent magnet can be static, as in the classical horse-shoe form, with the transformer windings rotating between the poles, or sometimes the magnet is mounted on the armature and rotates within the core of a static winding. 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. How to 'Kill' a Lucas KVF Magneto? - Vincent H.R.D. Owners Club Forum Grease. If there is a difference, adjust the points so that it is the smaller gap that is 0.012 (0.3 mm). pages on how to do that. I do not know it all but I will try to help. Just to reinforce a point here of something very well done that you did in the how-to: when you're testing a mag like this, ALWAYS have the plug wires hooked up with a gap (or plugs) to ground so that energy has somewhere to go. and other magneto parts. 0000000783 00000 n 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. Turn the armature in its proper direction of rotation until the contact-breaker points are just starting to open on one of the cam lobes. It uses a magneto and a transformer to make pulses of high voltage for the spark plugs. Check that the spring of the pick-up brush is good, that the brush is free to move in its holder and that it is not unduly worn in length or diameter. I pulled my B34 out after the winter and could not get it started. After you get your spark strong enough, then worry about cap and rotor. rectifiers (and wiring diagrams) of use to all Now let the slip ring dry out with the pick-ups still removed. With the mag on the engine, there is a spark at all 4 plugs . I can never stress this enough to people who try to test out their mags. 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. Place a clean piece of strong paper between the points, and with the points closed pull the paper out. The irony here is that usually these magnetos fail to spark. xref magneto electronic ignition conversion, repairs Lucas & BTH, 5 year If you need more information, or wish to order by post or pay over the phone, please ring: 01273 913181. Check that the felt pad in the end of the screw holding together the two blocks of the points assembly is present and good, and soak it in oil. The ratio of turns in the secondary winding to the number of turns in the primary winding, is called the turns ratio. Comment Guidelines: Do post respectful and insightful comments. Put a smear of grease on the lobe(s) of the cam. Many should appreciate. Thank you for your patience. -- Tickover, pulling away, and low-speed running erratic. The reading should be substantially the same as the reading you obtained in the internal HT continuity section. The original coil may be reusable, although it is susceptible to faults - as described in our section: common problems on magnetos. Learn how and when to remove this template message, https://en.wikipedia.org/w/index.php?title=Ignition_magneto&oldid=1150712364, Short description is different from Wikidata, Articles with unsourced statements from January 2023, Articles needing additional references from January 2023, All articles needing additional references, Creative Commons Attribution-ShareAlike License 3.0, This page was last edited on 19 April 2023, at 18:38. If the brush is missing or there is only a very short piece in the pick-up, the brush (or part of it) may have come out and dropped to the bottom of the magneto housing. 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). Your mag likely has a bad condensor. The spark is fine on this coil, keep in mind the faster you turn a mag, the better the spark. 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. Turn the armature in its proper direction of rotation until the contact-breaker points are just starting to open. [7] Ignition magnetos were soon was used on most cars, for both low voltage systems (which used secondary coils to fire the spark plugs) and high voltage magnetos (which fired the spark plug directly, similar to induction coil ignition). that more owners can not only maintain their magnetos, 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. Nederlandse magnetos. SR1, SR2 & SR4 magnetos (workshop instructions) Powered by Invision Community. If there are any, replace the pick-up. However, dont make them lop-sided. Recommendations for Lucas K2FC magneto rebuild? - Britbike forum Values vary considerably depending on the make and model of magneto and who wound it. When we undertake the renovation of these magnetos, we examine the following:-. From the basic to the complex - some and overhauls. If you are having trouble with your ignition system we recommend that you first change your spark plugs and HT leads. 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). or but enjoy doing it, with confidence, relying on the 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. 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 . 2,330 views Oct 18, 2020 16 Dislike Share Air Fuel Mixologist 1.31K subscribers I purchased this Lister D petrol (gasoline). A simple magneto (an electrical generator using permanent magnets) is able to produce relatively low voltage electricity, however it is unable to produce the high voltages required by a spark plug as used in most modern engines (aside from diesel engines). The result in high resistance will reduce the current flow in the primary winding and reduce the magnetic flux which adversely effects the secondary winding output voltage. Initial installation does require the Timing Lucas K2F and K2FC Magneto | Jockey Journal Forum AJS and Matchless Owners Club Limited | Print Article - Jampot Twin sparks provide two flame fronts within the cylinder, these two flame fronts decreasing the time needed for the fuel charge to burn. 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. Joined: Oct 2009. Thanks mmcdonald, all good info. 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. I highly doubt it is excessive unless someone has been grinding the rotor or the cap. information aggregated from many sources. Lucas SR2 Magneto - Hitchcocks Forum 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. It shouldnt be very many ohms, and certainly less than 30 ohms. Lucasworkshopinstructions-magnetosLucasworkshopinstructions-otherstuffLucaspartslistsLucasATDspecificationsBTHinstructions&partslistsM-LBookletsMagntoFrancedocumentationRobertBoschDocumentationAmericanBoschworkshopinstructionsPatentsBooksandlearndpapers, Redesigned contact breaker for ring cam models, SR1, SR2 & SR4 magnetos (workshop here. any service or repair work until further notice. It may not display this or other websites correctly. Lucas KF2 magneto failure - Britbike forum many ignition systems, focusing especially on 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. The reading should be between 0.5 and 0.7 ohms greater than your first reading. degrade with age. 0000001320 00000 n These are prone to deterioration and the cause of many ignition faults. patterns for shims, gaskets and bearing 0000003777 00000 n 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. At least I assume so: My timing light (seen in photo clamped to plug wire #1) illuminates correctly when plug #1 is unscrewed from the engine and sparks, but it does not light up when the plug is screwed into the engine. I have seen that a lot on FM mags. If you are sure that all earth brushes are removed, and if either the magneto has a fibre drive pinion or the drive pinion/sprocket has been removed, you can now check the effectiveness of the bearing insulators. Posts: 34. IMPORTANT. We also have kits for more unusual magnetos, such as the BTH, ML, Magnetos France, Morel, Lucas wader, Lucas KVF, etc., and for cars. ring. 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. With the Lucas KN1, it is under the identification tag. classic vehicles generally. 1. This was examined earlier. Put a smear of grease on the tappet shaft. Electrical - Armature windings, Condenser, Slip ring, Points and Bushes. Magneto: No Spark - Antique Automobile Club of America The coils are, of course, designed for this pressure but no insulation is perfect. Hi group, It is summer in Denmark, nice but my Lucas KF2 Magneto do not like high temperatures. Copyright 2023, Antique Automobile Club of America. I was hoping that some of the experts might help me with a magneto problem. 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 short circuit absorbs all the power, hence no output or spark. at some of the equipment we use in our workshop for magneto servicing (Chinese) Feel free to buy the forum staff a coffee or pint or just make a contribution of your choice. The high voltage will simply arc across the gap. %%EOF Capacitors, which are short-term storage devices, often fail in older magnetos due to dielectric degradation (short circuit) or conductor breakage (open circuit). making your own bearing and slip-ring pullers; Thanks. So I'm having an issue that is frustrating me and my mag rebuilder. (Japanese) dynamos, regulators, alternators and The readings for the two plug caps should now be swapped around. This was diagnosed as the cam ring not being properly timed to the magnetic poles. It's easy! 0000005952 00000 n As the magnet moves with respect to the coil, the magnetic flux linkage of the coil changes. 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. Clean and grease the moving-point pivot. Can you rig up real cables? With some magnetos, the main-body earth brush is accessible with the magneto in situ. Put a smear of grease on the surface of the cam that engages its housing. Carefully check for any cracks or pin-holes in the pick-up. 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. 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. Open the points and blow between them to dislodge any remnants of paper. Will It Spark? We also sell our Brightspark range of So, re-check everything in the contact-breaker assembly first before deciding on a more complete overhaul. Check that the advance/retard mechanism reliably rotates the cam back and forth. 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. to suit the needs of a customer. magnetos available for sale or in I would narrow the plug gaps to .020" and see what happens. I got it back, spun it, sparked. 0000001569 00000 n The wires are copper core with non resistor caps. 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. Please note: THEY ARE NOT FOR SALE! Make sure they are there and can move in their holders and give them a good clean. The last of these possible reasons is very often the cause. A second coil, with many more turns than the primary, is wound on the same iron core to form an electrical transformer. With a multimeter, check the resistance between the brass of the slip ring and the end of the armature shaft (armature earth). 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). found in all rotating-coil magnetos. Take a look If an earth brush is fitted behind the back-plate, check that the spring is good, that the brush is free to move and that it is not unduly worn in length or diameter. In the Lucas MO1, it is on one side, adjacent the contact-breaker housing. unfortunately the repair did not work as the Coil did not work so it had to be sent to rewinding. Espaol If you are using an auto-advance timing gear, stuff a length of fuel line in the mech to hold it at full . Thank you for your patience. For a better experience, please enable JavaScript in your browser before proceeding. The turns ratio between the primary and secondary coil is selected so that the voltage across the secondary reaches a very high value, enough to arc across the gap of the spark plug. This can mask a fault on these cars as the vehicle will continue to run until the other fails. Check out our magneto armature winding service. 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. 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. wish to make the required puller tool information as we can about the electrical equipment Once the insulation has been broken down once, it often makes it easier for it to be broken down again. If the brass is black, it indicates that the brush(es) are too soft and/or years of neglect. In the right direction (clockwise, looking at the points) and a fairly healthy looking spark should jump the gap from one ht at a time, lead to casing. The points gaps with the heel at the centre of each lobe of the cam should be the same, but a small difference is inconsequential. Repeat with clean pieces of petrol-moistened rag, until the rag comes out clean. The points surfaces should be very slightly convex, so dont worry about getting them perfectly flat. DO NOT ATTEMPT THIS IF YOU ARE FITTED WITH A PACEMAKER, OR HAVE A HEART CONDITION, OR IF YOU REALLY HATE ELECTRIC SHOCKS. The air gap between the rotor and the cap actually increases spark output as long as it's not excessive. A forum community dedicated to Jockey motorcycle owners and enthusiasts. The voltage generated across magneto coils is quite high, in the order of 20,000 volt if no spark plugs are in place. detailed instructions in our 'condensectomy' Then measure the resistance between the two points of the contact-breaker. 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 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. Thoroughly clean the pick-up using a rag moistened with petrol. B Magneto Help - No Spark - Britbike forum This is really common on original units as the Lucas condensers were made from wax paper and foil. If there is a main-body earth brush and it is accessible, remove it and check that the spring is good, that the brush is free to move in the holder and that the brush is not unduly worn in length or diameter. If it is an original capacitor then it will almost certainly fail because of its age and the materials and techniques that were used to construct them. As the voltage of the primary winding rises to several hundred volts,[3][4] the voltage on the secondary winding rises to several tens of thousands of volts, since the secondary winding typically has 100 times as many turns as the primary winding.[3]. slip rings and pick-ups for Lucas and BTH "A Community of Antique Engine Enthusiasts." troubleshooting your magneto. If youre giving your magneto a thorough check over, we suggest you tackle jobs in the order shown. 0000007301 00000 n Another cause of atom disorientation is mechanical shock, hammer blows or dropping the unit onto a hard surface, etc. 0000002567 00000 n If not free to move, ease it. 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. With Lucas devices, the fixing hole at one end of the contact-breaker spring is slotted so that the effective length of the spring can be adjusted as necessary. To have the discharge go arc back into the coil itself or the mag housing causes some serious damage. We provide Over time the HT leads can degrade and reduce the potential difference at the spark plug. BTH mags utilized condensers made from mica. Capacitors are replaced with ones that have a longer life expectancy and greater reliability. commonly found on classic motorcycles. There is no wire hooked up to the cap. heavier the better. Stored in the dry. If necessary, dress the points on a fine stone. On many Rolls Royce models there is a dual ignition system. If the pick-up is retained by spring clip, swing it to one side while holding the pick-up in place. When screwed in the head, however, the plugs make no spark. Thorspark magneto ignition repair FAQ - Sussex motorcycles tour of some of our specialised workshop U.S. agrees to $5 million settlement over police killing of Bijan 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. Now line up your degree wheel with the pointer at 38*. Gift Article. The resistance between the two sides of the circuit board (with your fingers well clear) should climb to in excess of 2 G (2000 M). Fantastic! instructions). things we think matter when it comes to magnetos and. 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. I was bench testing by tuning the mag slowly by hand, without the impulse coupling attached, so 1/4" is a good distance. JRC Engineering Inc. 3110 Indian Ave Unit 1E, Perris, CA, 92571. If the coil has been in service since the magneto was new there is a good chance the insulation has started to break down, allowing voltage to track. Post in the forum instead. PDF LUCAS MAGNETOS - edknet.de We always replace the capacitor during a repair as experience has show us that the capacitor tends to be the most unreliable part. Pick-up brushes of the highest of which is the product of Brightspark Magnetos Ltd's

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