Topic: Broken timing light or weak spark?

[elquenada]

i got a used sears timing light and dwell meter a while back on ebay.  i was trying to use the light this weekend but the strengh and consistency of the strobe was very weak except on cylinder two.  The cylinder two plug wire produces a constant strobe whereas the other plug wires only give off an ocasional flash here and there. 

The plug readings look pretty good as far as can tell (light tan).  I also tried grounding the spark plugs to the engine and found that although plug two looks a little stronger, all plugs had a visible blue spark.  do you think my light is busted?  if not should I install new cables?  I read the FAQ and the new cable install doesnt look that hard to do.

ps-i have a stock setup with a Dyna S ignition and NGK plug caps. (PO installed it) Plugs are D8EA.

[Deltarider]

First make sure your HTleads are clean and free of grease. Be aware of polarity when you clamp the induction trigger on a cable. On our bikes "This side towards plug" is true for only two of the four cables. For the other two it's the other way around to get the strobe function. Close clamp well.

[dave500]

is the light 12 volt powered,is the battery good ?does the bike charge well idling?if the voltage is low the light may suffer.

[Yoshi823]

I used to work for Sun Electric (now part of Snap-On) & repaired there diagnostic equipment. One day I had to repair a customers engine analyser as his strobe was defective, a common situation when the strobe was dropped. After doing the repair I checked it on a simulator & all was working ok. A few days later I had a recall as the customer reckoned that the Sun machine was 'out' when compared to his Snap-On timing light. After I got the customer to attach both pieces of equipment to a common source, it transpired that the RPM pickup magnet shapes were broken on the Snap-On light. This was also a common occurance as the shapes were quite easily broken if dropped or clamped shut over the ignition lead when the lead was not in the 'U' shaped bit.

[elquenada]

great info. my battery is brand new and fully charged.  it also appears to be charging when i raise the rpm and put the multimeter to it.  I didnt know that some of the leads had reverse polarity so i{ll definitely check that out.

as far as what yoshi said..im not reallt sure what to make of this.

.

I used to work for Sun Electric (now part of Snap-On) & repaired there diagnostic equipment. One day I had to repair a customers engine analyser as his strobe was defective, a common situation when the strobe was dropped. After doing the repair I checked it on a simulator & all was working ok. A few days later I had a recall as the customer reckoned that the Sun machine was 'out' when compared to his Snap-On timing light. After I got the customer to attach both pieces of equipment to a common source, it transpired that the RPM pickup magnet shapes were broken on the Snap-On light. This was also a common occurance as the shapes were quite easily broken if dropped or clamped shut over the ignition lead when the lead was not in the 'U' shaped bit.

[Deltarider]

That inductionclamp is very delicate indeed. That's why on many you'll find the warning: Do not drop. I'd like to add: avoid any impact!
BTW, you'll have best results when the strobe is fed by an external battery. I don't know why this is, but that's the way it is.

[elquenada]

BTW, you'll have best results when the strobe is fed by an external battery. I don't know why this is, but that's the way it is.

ok well maybe I will use the 12v battery off my scooter to power it and see what happens. thanks.

[Gordon]

Try pulling the plug cap off the spark plug and resting it on top of the plug so there is a small gap between the cap and the plug, but not so large a gap that the spark can't jump it.    

I'm not exactly sure why this works, probably something about added resistance in the circuit, but I've had to use that trick on my old VW as well as a few motorcycles, and it works well.  

[elquenada]

Try pulling the plug cap off the spark plug and resting it on top of the plug so there is a small gap between the cap and the plug, but not so large a gap that the spark can't jump it.   

I'm not exactly sure why this works, probably something about added resistance in the circuit, but I've had to use that trick on my old VW as well as a few motorcycles, and it works well. 

interesting tip. i'll definitely try that this weekend when I can get back at the bike. too bad it looks like snow is coming so i doubt a test ride will really be possible.

[Deltarider]

interesting tip. i'll definitely try that this weekend when I can get back at the bike. too bad it looks like snow is coming so i doubt a test ride will really be possible.

Why? It's against the laws of physics. It's in fact an extra threshold. If there's not enough energy to jump the gaps and as a result the energy in the coil can't go anywhere, it could ruin your coils.

[Gordon]

interesting tip. i'll definitely try that this weekend when I can get back at the bike. too bad it looks like snow is coming so i doubt a test ride will really be possible.

Why? It's against the laws of physics. It's in fact an extra threshold. If there's not enough energy to jump the gaps and as a result the energy in the coil can't go anywhere, it could ruin your coils.

Like I said, keep the gap small enough that the spark can jump it.  It works.