Using a buzzer to set magneto timing

[huddie]

Hi you guys, I have just aquired a magneto synchroniser to use for the timing on my 57 flash. When I switch it on having connected one of the two magneto cables to the points centre bolt and the other to ground, the buzzer and the light from the spare magneto both come on immediately. Any ideas how to isolate the second mag half of the unit.
One of our regular contributors G/F Dave says he uses one, I have sent him a personal message via the forum but I am not sure how the messaging works, so i do not know if he has seen it
Regards Huddie

[alanp]

Huddie, I'm interested in this one since the old cigarette paper technique drives me to distraction.
Using my multimeter I can detect a small change in resistance from the centre screw to the contact spring between on and off, but a light/buzzer would be better still.
Alan

[G/F DAVE]

Hi, Huddie I dont know which model sychroniser you have but mine came from   las aerospace ltd  model e50 .This has three leads right & left hand mag and ground lead.I use it same as yours centre bolt on points (either rh / lh mag lead  and ground to ground .Once points break it buzzes simples!!!  as that rat on the tv add says...You may have a resistance somewhere or a faulty unit I would check on another mag if you can . Anyone wishing to buy these buzzers they are around the £75.00 mark now you wont regret it nor will your engine. Dave....

[a101960]

Once points break it buzzes simples!!!  as that rat on the tv add says..

Even more seemples is this LED device. It's what I use

http://www.frost.co.uk/item_Detail.asp?productID=9247&frostProductName=Magneto+Timing+Light+

John

[huddie]

Hi dave, thanks for getting back to me. Mine is a new E50 from LAS Aerospace same as yours. Only arrived today I hope it is not faulty but dont know how to check it as I dont have access to another mag. Am I assuming right that on yours the second red lead is not connected to anything and you get no buzz or light on that side of the meter. The bike starts and runs ok so can I assume from that, that the mag is not the cause of my problem?
Regards Huddie

[alanp]

Thanks A101960, I've just ordered one.
Alan

[huddie]

Please help my lack of understanding if you can. In trying to work out wether my new buzzer/light magneto synchroniser is faulty or not I tried the following, Please bear in mind that with the buzzer/light connected it failed to light or buzz when the points opened!. I connected a simple circuit tester with an internal light from a power source ie the battery to the moving contact on the points. With the points closed the light is on. With the points open the light still stays on!, surely it should go out?. Likewise with the mag synchroniser it should be light/buzzer off when points are closed , on when points are open. As per earlier text I get no light/buzzer points closed or open. Any ideas please.

Regards for now Huddie

[a101960]

I connect my unit by clipping one of the connectors to the centre bolt on the points plate and the other connector to any convenient earthing point. You do not have to clip directly to the mag body although this is O.K. Do not make the mistake of trying to connect across the points. As an aside I connect the degree disc to the crank shaft on the timing side of the crank. I find this more convenient. This is achieved by tapping the opening in the end of the crank. The opening is not very deep so you will only get about three to four turns at the most, but it is enough to permit the screwing in of a bolt which has the degree disc attached to it. I think that it is a lot less hassle doing it this way. The advantages are that you only need to remove the timing cover and do not have to disturb the primary cover and that because you are using an LED/buzzer you can do everything from one side.

John

[huddie]

Thanks for your input John but I need to prove if my meter is working correctly or not. Am i right that when connecting a "light" to the moving contact it should go out after the points open??.

Regards Huddie

[a101960]

I tried using a meter and was unable to detect any indication. I also tried a lamp without success which is why I purchased the LED unit.

John

[groily]

On the Q 'why won't the bulb go out?', it's because of the way the mag is built. The fixed contact point (insulated from the backplate by a mica washer) attaches to the low tension coil one end via the centre screw; the other end of the low tension coil goes (via the condenser) to the mag body. The moving contact is connected directly to the backplate by the little screw on the spring. The backplate is connected to the armature spindle at the brass taper, and thence to the mag body. So both contact points are effectively connected to the body of the mag. Don't know what the resistance in a low tension winding is meant to be - an ohm or two maybe? Not much anyway.
So a bulb with an external power source put across the points will light up and stay lit, and the difference in resistance won't make that much odds to how brightly it shines.  Hence something else is needed. Like a Rizla, a 1.5 thou feeler gauge, a sensitive analog meter like an AVO, hawk-like eyesight to see when the cam ramp starts to open the points . . . or a proper buzzer. But as to why your buzzer's buzz has buzzed off, I'm afraid I've no idea!