Timing strobe light

Onder

Onder

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My old strobe died so I borrowed another. This one has a dial on it to advance the timing. Im clueless as to what this is for and how it works. Seems to me that setting this at zero is the way to go. Can somebody explain the obvious to an increasingly dense old man?
 
The dial is probably to allow you to set degrees of advance while pointing the strobe directly at TDC, (or some other reference point). I must admit I do not find this feature very useful with my bikes. However, with my MG MGC, the timing marks on the front of the timing chain cover only go up to 10 degrees btdc. At idle, my car is happiest at approx 15 degrees btdc. So, I set the timing strobe to 15 degrees of advance and set the timing so the light points directly to TDC.
 
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You don't need a scale on the engine, just aTDC Mark. You set the advance you want in the timing light and observe if the TDC marks line up at whatever advance/RPM you want to check. It's more accurate than the usual "scale" on the engine. I seldom use the engine scale, just timing light adjustment.
 
OK will do, thanks.
I notice they now sell strobe lights with a tachometer on the gun so you can watch the pointer whilst bringing the engine speed up to whatever you must have. Otherwise you need two people one to run the throttle , the other to watch the pointer.
 
A gun with advance can be used to determine set/check timing at idle and when the scale doesnt have markings for desired degrees. You just watch for pointer to hit a TDC mark while you change the strobe flash degrees. Then you have a degree reading at the idle rpm. Not important for our bikes which only have a single advance curve mechanism, but many cars have multiple advance controls like vacuum advance, distributor weighted mechanical advance etc.
 
Onder said:
OK will do, thanks.
I notice they now sell strobe lights with a tachometer on the gun so you can watch the pointer whilst bringing the engine speed up to whatever you must have. Otherwise you need two people one to run the throttle , the other to watch the pointer.
Click to expand...
What a blindingly obvious and brilliant idea !!
 
Im sure somebody will tell me that they can tell the rpm by ear as they crouch over the timing window
shining the strobe and watching the moving line on the rotor. :-)
I have noticed it is a lot easier on a Triumph which has no chain driven cams.
 
Onder said:
Im sure somebody will tell me that they can tell the rpm by ear as they crouch over the timing window
shining the strobe and watching the moving line on the rotor. :-)
I have noticed it is a lot easier on a Triumph which has no chain driven cams.
Click to expand...
If you want to contradict me, there’s no need to be obscure about it.

On common Boyers and Wassell ignitions, you're supposed to rev it up to 5000. You can open the throttle until it reaches 5000 on the tacho, then look at the timing mark and pointer, holding the twistgrip steady. You’ll know by the sound of the (roaring) engine if you’ve inadvertently let the revs vary.

The last thing I want in the shed is other people “helping.”
 
I like the idea of the tach/strobe. Last time I timed the Norton my wife was in charge of the throttle control and calling out tach readings. I had to work fast as she was rapidly losing interest...
 

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