Topic: Timing light issues

[Paul Lowe]

Have a standard clamp type timing light I have used over many years. It only works intermittently on my cb750 k1?  Tested it on other systems and it is fine.
Have new coils points and plugs.  Bike has had issues but can't fix without timing??

Is the wasted spark system part of the problem?  Have swapped most things but still same same...

I wanna vroom!

Paul

[scottly]

The wasted spark system on these bikes produce a different polarity spark for the 2 cylinders on each coil.  My timing light has an arrow on the clamp that points towards the spark plug. Try reversing the clamp, or moving it to the other wire from the same coil.

[MoMo]

The wasted spark system on these bikes produce a different polarity spark for the 2 cylinders on each coil.  My timing light has an arrow on the clamp that points towards the spark plug. Try reversing the clamp, or moving it to the other wire from the same coil.

That has worked for me so I'll second that

[evanphi]

The wasted spark system on these bikes produce a different polarity spark for the 2 cylinders on each coil.  My timing light has an arrow on the clamp that points towards the spark plug. Try reversing the clamp, or moving it to the other wire from the same coil.

That has worked for me so I'll second that

I'll third, just to make Paul feel silly. (Also I had the same problem, got mad, and then figured it out...)

[Paul Lowe]

Not feeling silly, did that still no flash!

Occasionally it flashes but never at high revs?

[scottly]

Is it the same for both coils, or just one? If just one, you may have an issue with the points that feed that coil. If both, try powering the light from a separate battery.

[Deltarider]

The HT lead should be clean and free of any grease. If not clean, clean with some alcool. The clamp (caution: don't drop it, they are fragile) should be closed fully. If there is no reading the clamp should be - how do you say? - turned around? This is for polarity reasons. External battery isn't a bad idea either,

[Paul Lowe]

Leads new, points swapped, clamp ok, turned all ways still no good?  Put timing light on car and it's a nice consistent disco light!  WTF

[scunny]

move bike from garage, replace with car. dance party. bugger too old for that #$%*.
had the same problem years ago on my 500, never did find a solution, shall wait for updates.

[DH]

This seemed hazardous to me when I heard it but, a long time ago, maybe on this forum, somebody had this same problem.
The solution was to wrap tinfoil around a section of the plug wire, then place the clamp over that. Not Saying it's right, will work,
whether or not its hazardous, or anything else. Maybe someone with more knowledge will add? I've not tried it, but would hook it all up with the engine off, obviously, then see if it makes for a better "signal"(?) Anyone know if there's any truth to this?

[Paul Lowe]

Will test and report. Maybe I should wear a tin foil hat too...

[MoMo]

Will test and report. Maybe I should wear a tin foil hat too...

or maybe hire The Tin Man to do it

[scottly]

Try powering the light from your car battery with the clamp on the sohc...

[evanphi]

Try powering the light from your car battery with the clamp on the sohc...

This could be fun... A low battery would cause this problem...

[70CB750]

Interesting, my cheap timing light never gave me trouble.

Just yesterday I tried it on the K3F, just turning the engine over with the starter to see if I have spark on every cylinder. 

[Rgconner]

Try powering the light from your car battery with the clamp on the sohc...

This could be fun... A low battery would cause this problem...

Even if it is not, you will get a more steady light, less jitter. Presumably because of the fluctuations in power from the alternator.

[becken]

with one timing light I had, when using a separate battery, it wouldn't work right until I ran a jumper wire from the battery negative to a ground on the bike

[Vinhead1957]

One light I had a direction on the pickup towards the spark plug