I've often used a strobe on any of my singles. A great way of checking accuracy. I usually use a degree wheel to set the timing as I find measuring down the cylinder vague and difficult. Not saying it doesn't work.

I draw a degree wheel on paper, I'm fortunate to have a CAD application, but theres nothing wrong with a pair of compasses, pencil & rule..!!

I make this about 4" in diameter. Measure the size of the hex on the crank nut and draw this on the degree wheel as well. Paste it to a piece of card, something like the breakfast cereal cornflakes box.

Cut this out including cutting out the hex for the crank nut. If you cut inside the lines on the hex you will make the hex hole a tiny bit small, so when you push it on the hex it will stay there.

Then attach a piece of wire under a convenient nut somewhere near where TDC will be on the degree wheel then go ahead and set up the wire to TDC. The best way is to have a stop bolt fixed through an old spark plug so the piston is 'stopped short before TDC. Check the degrees on the card, rotate the engine the opposite direction until it stops again, note the degrees. Accurate TDC will be half way between the two readings.

Books say set timing at full advance, so move your lever in whatever direction to achieve this and set it up there. #* degrees, 35 degrees, whatever your cuppa is......

Put spark plug back in, leave card degree wheel on crank. Connect stobe light HT pick up lead to spark plug lead. I have a spare 12V car battery I connec the power wires of the strobe to.

Start bike & check setting with strobe on card degree wheel. It should be what you set it to against the wire pointer. It's easy. The card is small & light and will usually stay on the crank nut. Its mass moment of inertia is nothing, so it usually does no damage to itself or anything else.

Interestingly you can retard the ignition back on the lever and see what the full retard setting is.

Often I've found the full retard setting is actually ATDC, may be 5 or so degrees. I have tried setting the timing at TDC on full retard and see where it is at full advance and have left it at that.

My 16H runs quite well, it is a reliable starter and runner. Is heaps fun to ride, I always give it the berries, it loves it. Will pull the retard lever back a bit on long up hill slogs. I have never noticed and knocking.

Bob

Wow Bob, thank you for a very informative and detailed answer!

Your method is exactly the one I have been using through the years. I have made several disk copies [how modern this sounds for a hard copy of a very simple paper disk] for various bikes. I find checking the timing and advance of the 16H with a disk once in a while when the primary chaincase is off, very easy and accurate.

But I never succeeded in getting the strobe to flash on the 16H. It does in the same setup (also the same setup you describe, with an external 12V battery) on a 6V BMW-magneto system, but not on the 16H. I suppose you have more or less the same strobe as I do, with a red positive and a black negative battery clamp, a high-tension pickup (directional, with an arrow indicator) and an extra clamp (green on my Optilux strobe), normally connected to the distributor.

Does your strobe have this extra clamp too? And if so, where do you connect it to?

Peter

Hi Peter,
The strobe usually works, sometimes it's a bit intermittant. I guess it's all to do with how good the impulse pickup is on the spark plug wire.
My strobe light is a simple cheapish power strobe bought from an aftermarket auto parts outlet. This particular strobe does not have the extra wire you speak of, but I had another that did have this wire. There was an analogue dial on the strobe gun, the extra wire went to the distributer and you could check dwell angle. Don't know how or if this would work with a magneto.
I have a 1994 Harley davidson Electraglide, evolution motor. These motors had two methods of sparking the plugs, both plugs together with a waste spark on the exhaust and both individually (seperately. Mine fires both at the same time. They are a terrible motor to set ignition timing on with a strobe light, but mine will not work on the rear cylinder, only the front. I do have a magneto on another Norton that the strobe won't work on as well. Maybe something to do with type of spark plug wire.

I bought an electronic tacho (engine revs) that was supposed to work on these engines. The type that is used on go carts and other motors with self energising ignition. Unit has its own small battery, like a bicycle speedo and a wirethat wraps around the spark plug lead. I could never get it to work properly. Readings would be all over the place....!!!

Bob

Since a strobe is only going to give you standard timing and as fuel is now different now I can't see the point. My M21 was rebuilt as a magazine project bike with the the timing set exactly. It was wrong. I had to advance it a bit to get it running just so.
Oh and whilst the military specified 50 for the engine Pitman quotes 40 for winter and 60 for summer. The army just standardised not optimised. I don't know if Morris do a straight 60