Point Timing, Test Lights, "Test Lights" & Other Gadgets

[jpdevol]

Note: Yamaha has long specified that contact breaker points be set with a timing light and that is how the later service manuals describe setting points’ timing and verifying advance function. When timing lights are not available – alternative methods are sometimes employed to determine initial static timing.

I have sensed some confusion out there in XS land regarding gadgets called “test lights”. There are, on the market today, two kinds of test lights; one tests for voltage and another tests for continuity. Both types look very similar, but with major differences – polar opposites.

The voltage tester does not have its own power supply. It is used to test “live” circuits (key on). One “lead” – typically a clip (clamp) - is hooked to ground (aka battery negative [-], the frame or engine, earth). The other lead (point) is used to find voltage in a circuit; typically, at a connector, terminal, etc. Most old-timer mechanics have this type. If you touch its two leads together, it does nothing.

The continuity tester must have its own power source, by design – usually a battery AA (AAA). It is used only to test circuits when power is off or the circuit is unhooked. It can be used to test the completeness of a wire, the function of a switch, integrity of a removed fuse. The clip is attached to one location in the circuit (or to ground if appropriate) and the point is contacted to another location to determine if they are connected (electrically). Most “home centers” sell this type. If you touch the two leads together, the light comes on (assuming good battery).

To compound the potential confusion above, either type can be used to test points (other switches) and their timing.

Voltage testers need to have the circuit powered (key on) and all the wiring hooked-up. The light will come on when the points are open.

Continuity testers must have the key off and (ideally) the points wire should be unhooked at the connection to the coil. When the points are closed, the light will come on.

Ohm meters (aka multi-meters), “buzz-boxes” are continuity testers.

 

[toglhot]

I knocked up my own static timing lights. One uses an LED hooked up to a button battery holder, another uses an LED hooked up to a 9 volt battery clip via a resistor. The third relies on the bike battery via the ignition on, but I don't like using that one.
The button battery one is super easy to make, everything available from electronic stores. The 9 volt battery one is a bit more robust and heavier. You could also make one from a AA or AAA battery, or any other battery for that matter, or If you don't have a battery carrier, the leads can be soldered straight to the battery. Most LEDs require around 2 or 3 volts so using a voltage over that will require a resistor. Any globe will work: festoon, incandescent, but LEDs are small, robust and last forever.
Cost, just a few bucks.

 

[RustiePyles]

Here's a link to the buzz box I built
https://www.xs650.com/threads/der-buzzmacher-or-diy-magneto-buzz-box.58493/

 

[jpdevol]

Here's a link to the buzz box I built
https://www.xs650.com/threads/der-buzzmacher-or-diy-magneto-buzz-box.58493/

Great job on the buzz box!

I've got an older store-bought one (as in pic). In addition to magneto systems you mention, they make it easier to time all the 2-stroke RD's with AC systems. There are no timing marks! The specs for points is given in mm BTDC. So a dial gauge set-up screws in the spark plug hole to measure millimeters BTDC: hard to watch the dial gauge and anything else simultaneously. The audible "buzz box" - to sound points' opening - is a practical requirement!

 

[toglhot]

Or you can do it the simplified way, buy one of these and hook it up to a battery and alligator clips.

 

[Team Junk]

Several of my VOMs have it built in.

 

[WideAWAKE]

Great job on the buzz box!

I've got an older store-bought one (as in pic). In addition to magneto systems you mention, they make it easier to time all the 2-stroke RD's with AC systems. There are no timing marks! The specs for points is given in mm BTDC. So a dial gauge set-up screws in the spark plug hole to measure millimeters BTDC: hard to watch the dial gauge and anything else simultaneously. The audible "buzz box" - to sound points' opening - is a practical requirement!

On my Lambrettas which have no timing marks, I use a Buzzwangle -

Used to always use a degree wheel and pointer but this is much faster and accurate.

I havnt had a need to try and adapt it to another bike but I’m sure it wouldn’t be too difficult.

 

[RustiePyles]

Great job on the buzz box!

I've got an older store-bought one (as in pic). In addition to magneto systems you mention, they make it easier to time all the 2-stroke RD's with AC systems. There are no timing marks! The specs for points is given in mm BTDC. So a dial gauge set-up screws in the spark plug hole to measure millimeters BTDC: hard to watch the dial gauge and anything else simultaneously. The audible "buzz box" - to sound points' opening - is a practical requirement!

Yeah, I built it to time on my DT's ac ignition system.

 

[LTGTR]

A method that works very well is to have a cheap and small transistor radio switched on but not on the station properly - some static - when the points break or make (cant remember now) there is instant increased static.
Regards Ray.

 

[RC4MAN]

Generally used the Buzz function on my VOM to do a basic static timing prior to warm up and a dynamic with a timing light at speed to verify advance. The Jap bikes generally were easier as they had both idle and advance timing marks, the Brit bikes you had to remove the retaining bolt for the advance unit, place a washer under the bolt head, rotate the cam to the advanced position and snug the bolt to hold it advanced while you checked it because the rotor only had the advanced timing mark.