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Timing Boyer / Pazon

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As we all know, timing the lightweights using markings on the alternator rotor and a pointer on the stator is the usual method advised. It's especially tricky on the Electra with the starter mechanism obscuring the relevant parts, and in any case needs the primary cover to be removed and the engine run with consequent flailing chains and oil everywhere.

A post on the facebook light twins page gave me cause for thought. Boyer an Pazon are both set up by setting the engine on full advance and lining up the magnet with an appropriate hole in the PCB.

My thought is that if I paint the magnet heads a suitable bright colour, I should be able to check the timing using this and a stroboscope. I should be able to see the magnet through the hole, and it should approach and reach centrality as the revs rise.

Any thoughts?

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If you can accurately mark where the magnet or rotor is at 30 degrees BTDC (is that correct for an Electra?), then maybe your system could work.

Oil from chains isn't the biggest problem in the world though, and the alternator rotor is bigger than the trigger rotor and turns at engine speed, so timing to a mark on it will be much more accurate.

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Ian,
The way I see it you need two accurate non adjustable points to check the ignition with a strobe. A fixed static pointer secured relative to the engine case and an accurate revolving timing mark relative to the crankshaft degree showing the required ignition full advance. But this is what you are trying to avoid.

Your idea uses two variable points. First, the rotor which isn't/can't be positioned at any accurate position, rather it is roughly set on installation. Second is the variable plate which is in effect the means of adjusting the correct firing point for the spark. You have no accurate datum to strobe and measure the ignition point.

I understand your thoughts but to me it can't work for my reasons above. Hope this helps. Stan

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Ian, 
The timing procedure for Jubilee and Navigator with points is well described in the Norton Twins manual issued by AMC. 

I made an expanding mandrel that fits tightly into the crankshaft starter ratchet. An 8mm stud tightened things and provided the central mount for a timing disc. I thought removing the ratchet rediculous for a timing check. Photo attached. 

Obviously you have to remove the outboard starter sprocket and starter chain. 

Set the timing disc zero position with a piston stop. 

I find the Pazon can then be timed statically. 

And check the timing and advance curve with a strobe. The disc doesn't move if you keep the throttle action gentle. 

Peter 
 

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Ian, 

Photo of timing disc on expanded mandrel with pointer.

With electronic ignition set correctly, you can forget about timing going "off" as with points. No need for inaccurate approximate paint blobs on the rotor. 

Peter 

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Would it be possible to make a nut like the one in my first photo.  It has an external thread that the timing disc screws on to, second photo.  

A large diameter timing disc will give better accuracy than small diameter disc.  My disc is "adjustable" so I can use a substantial fixed pointer rather than a bit of bent wire.

This may sound like a lot of work for what may be a one-off setting.  My engine is a mixture of new, old and original parts, as they bed it may, or may not, alter the timing. I will check at some point.  Wear and tear might alter things, especially in a well used engine. 

One of the first jobs I did on the Navigator was fit a Boyer system.  I thought this is going to be a messy business, running the engine with the chain case cover off, oil everywhere.  needn't have worried didn't seem to fling oil at all.    

 

In reply to by john_crocker

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John, that looks a very professional set of tooling for timing a Navigator. Greatly admire the thoroughnesss. 

Your Navigator has a stud in the crankshaft end, thick washer and nyloc 1/2in BSF nut. Some threads exposed on the stud if you are lucky, which can be used to secure a timing disc that clears the alternator stator. 

The Electra does not have a stud. The ratchet takes the place of the thick washer. A bolt with a very thin head screws into the crankshaft end and must be secured by a tab washer of unusual shape. Inside the ratchet. Very hard to bend the tab onto the hexagon side. See the left hand detail of the first photo I posted. One tab is folded up, the other at 30 degrees is left unfolded. 

So unfortunately no chance to use a nut as you have made. 

I looked for a way of securing a full size disc without disturbing the starter ratchet and particularly the bolt and tab washer. 

Peter

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... but am trying to avoid the mess of trying to strobe a very inaccessible pointer / rotor relationship whilst being sprayed with oil....

This shows the pointer i have made (since painted red for visibility)  attached to a stator stud and the rotor. I have marked this at TDC and 30 degrees BTDC but those marks aren't shown. Of course I set those marks using the piston stop / degree disc as described so am confident they are correct. I think I have described elsewhere the use of a counterbored and tapped spare sprag clutch bolt for this purpose.

I maintain that as long as I carefully locate the marked Boyer rotor centrally in the hole in the PCB whilst checking (using my marks) that the crank is 30 degrees BTDC then this will be as accurate as the recommended method. Of course it will have to be viewed and strobed orthogonally to avoid parallax errors.

All this is a little academic at the moment as I have lots of other stuff to do. Recommissioning? Give me strength......

rotor marking

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On my web site is a pointer I made from a scrap of aluminium, usable on all lightweights. this gives a fixed point. And stays on the engine. I then found TDC and (30deg) of the crank/rotor going round by 'hand' and marked the rotor. So when engine is fired up you can see the (30deg) point coming towards the fixed point with the strobe. I can't remember any issues with chains/oil flying about, or the starter sprag getting in the way.

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... what I've done Al. But I still don't see why my method won't work. I accept it will only be about half the precision of measuring at the crankshaft.

Another consideration is that my medium range eyesight is very poor despite using varifocals so think this will be easier to see.

To someone used to timing an ES2 with a spoke and filed notches this is all a bit high tech. And I haven't used my strobe for at least 30 years. Will it still work? Who knows.....

A couple of pictures:

pointer

ro

PCB

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I don't think your blob appearing in the hole is accurate enough.  My 250 had to be accurate to less than two degrees, just like the book says.

Scribe a line in the white paint, lining up with a notch or line in the plastic baseplate at 30 degrees BTDC, having turned the crankshaft forward to that position.

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I was thinking something similar.

I have to say I would struggle to get within 2 degrees whatever method I used. And the Boyer is going to keep its settings, once done, far more accurately than points as said many times.

 



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