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Rob's WD16H and Big4 Forum

Dutch army, Johan Herman Fuhler, somewhere between 1945 and 1950

Rob's WD16H and Big4 Forum
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Using a strobe on ignition timing of 16H?

Hi,

I know it is in general fairly easy to time the 16H-ignition. I use a disc.

On my other non-magdyno machines I use a stroboscope to check the ignition. Would it be possible to use a strobe on magdyno ignition as well?

I did try it, of course, but no flash. Not even after connecting the strobe feed directly to the 6V 16H-battery, nor to an external 12V-battery.

Did anyone manage to use a strobe with the Lucas magdyno?

Peter

Re: Using a strobe on ignition timing of 16H?

Three questions come to mind:
a) why bother?
b) what marks are you looking at?
c) what's the 'best' timing position?
Books vary but the WD book gives 7/16" or 35 degrees. But when I timed mine very carefully to the book setting, it was sluggish and felt retarded to me. So I re-set to a shade before 1/2"... not much more I know, but it made a big improvement. Modern fuel is often complained about but it's a lot better than 'Pool'. They way I see it, if you set it bit too far, you can always retard it on the lever as long as don't forget to do so if it preignites. I've never persuaded it to 'knock' anyway and I've never needed to set the lever to full retard anyway.

Re: Using a strobe on ignition timing of 16H?

@David
a) Checking the ignition consistency with a strobe (shining at a degree disk on the LHS crankshaft) is fast, easy and a good tell-tale for ignition faults like contact errors etc. At least, I find it useful and comfortable with battery ignion systems, especially in twin engines, where you can very effectively compare both cilinders/ignition sides.

c) I have heard others too who ended up at 1/2" pre-ignition. Some state they set the timing with the advance lever in a semi-retarded position, which works out in the same way as setting it a bit earlier, I guess.

If I get the strobe to work with the Lucas magdyno, I might get it to work on my Ural/BMW R50 twin too, which also has a magneto ignition system.

I haven't yet got the strobe to work on a magdyno system. I was just curious. And still am: it is an extra tool after all. So if anyone has ever got it to work, I'd appreciate some advice.

Cheers,
Peter

Re: Using a strobe on ignition timing of 16H?

Sorry if my message looked a bit abrupt - no excuses. After about 50 miles on Saturday I have a vague suspicion of slight misfire so it serves me right.
I've just turned out the shed and re-discovered my old timing light. Maybe I'll give it a try. I need to take off the primary cover anyway - I used ATF in there and the clutch needs to be un-stuck every time I use the bike. I think the stuff may be OK for Commandos with peculiar metal plates, but not so with cork..
I quite liked having different oil colours in engine, gearbox and primary. Helps to identify any leaks!

Re: Using a strobe on ignition timing of 16H?

That's all right, David. Hope to hear how the strobe works for you.

By-the-by: I've heard of people using Hypoid SAE80 oil(normally used in hypoid gears and drive axle houses, eg in BMW's)in their britbike-gearbox and/or primary case. I haven't tried it, but it seams there is less leakage and (in the primary case)less clutch plate oiling.
And there is a bonus: it's a different colour!

Cheers,
Peter

Re: Using a strobe on ignition timing of 16H?

tangopeter


By-the-by: I've heard of people using Hypoid SAE80 oil(normally used in hypoid gears and drive axle houses, eg in BMW\'s)in their britbike-gearbox and/or primary case. I haven't tried it, but it seams there is less leakage and (in the primary case)less clutch plate oiling.
And there is a bonus: it's a different colour!

Cheers,
Peter


Hypoid 80 or 90 or any modern gear oil is a definate No No. Its no good for the bronze bearings in the gearbox and will make your clutch slip in the chaincase. Use what Norton recommended staight 50 in everything. I use Castrol GP50 still easily available in gallon cans. And you'll just have to put up with the garage floor being the one colour!

Re: Using a strobe on ignition timing of 16H?

Okay, point made clear. On the continent getting SAE50 (or SAE30) is no problem either.

Re: Using a strobe on ignition timing of 16H?

I can't argue with using the SAE 50 oil in the clutch case. But don't confuse Hypoid gear oil with EP (Extreme Pressure) gear oil which has the bronze destructive additives. Ron

Re: Using a strobe on ignition timing of 16H?

Hello Peter.

I have used a stroboscopic light on my BMW R60/2.
It worked fine and clearly showed left and right timing to be quite uneven.
From there I found I had to straighten the cone on which the advance mechanism is mounted. Apparently it had been damaged suffciently to make a proper adjustment impossible. (It is a rebuilt engine with unknown history)

I have never tried to use it on the 16H. The average motorcycle owner did not have those lights in the thirties and were still able to do it properly.
Keep it simple is my opinion. You don't have one with you at the side of the road when in need of tinkering. Its then better to have the experience without it I would think.

I used the 12V battery charger as power source and connected the negative of charger and strobe light to earth of the machine. Positive of charger to that of the strobe light. Quite straightforward.

Cheers,

Rob

Re: Using a strobe on ignition timing of 16H?

Well, there are a lot of things we like to use in our workshops nowadays that the average motorcycle owner did not have in the thirties, I guess...

And besides, I did have an, admittedly very simple, strobe light with me for my R50/2: a neon light (?) on a high tension cable with a plug cap on one end and an M5 bolt (which fits inside the BMW's plug cap) on the other end. If shaded from daylight, it did work, more or less. I have not tried that on the 16H, but will certainly do that, I hope this weekend. For old time's sake...

But you're right, it isn't necessary to check or adjust the rather coarse timing of a Lucas magdyno with manual advance on an single by means of a strobe. A 0.12" gauge, a cigarette paper and a piece of wire will do. Let's say that it is purely out of interest.

And I will certainly try again with your setup. (I did, more or less, with the on-board 6V battery and a 12V battery instead of a battery charger, but that didn't work. I am just curious why not.)

Cheers,
Peter

Re: Using a strobe on ignition timing of 16H?

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

Re: Using a strobe on ignition timing of 16H?

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

Re: Using a strobe on ignition timing of 16H?

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

Re: Using a strobe on ignition timing of 16H?

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