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Help strobe timing 1960 w/ distr. & Boyer ign? #786424 10/07/19 2:11 am
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The Momes of Wrath Offline OP
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It's a 1960 T100A unit 500cc twin.

This is a distributor bike timing marks for a strobe.
This ignition fits inside the distributor, so the plate is NOT adjustable, does NOT have timing marks, or a "white dot" I keep reading about for CW or CCW holes.
Instead, the entire dizzy rotates, and there's a single hole marked "TDC" for initial rough timing.

I was able to tap a small hole for a degree wheel and make a piston stop to find true TDC and set rough timing. I'm not sure what to do next.

The degree wheel and pointer are on the cam gear side so I can't run with that on. Do I pull the primary to get to the rotor and stator, scribe a line across both at TDC, advance __ degrees and scribe a new mark, then strobe until that aligns?

How many degrees?

The instructions say to set at "max timing" "with the engine running up to 4000 RPM". Does "up to" in this case mean revving it until 4000, or at most 4000?

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Re: Help strobe timing 1960 w/ distr. & Boyer ign? [Re: The Momes of Wrath] #786426 10/07/19 3:26 am
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NickL Offline
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Work on it on the primary side. As you say scribe yourself a line at 38 degs BTDC on the rotor.
Make a pointer up and scribe a TDC mark on the rotor as well, that way
you can re-use the pointer accurately without having to touch the timing side. (fit degree wheel etc.)
Always rotate the engine in it's running direction or you may find backlash in the timing gears
will give you an odd result.
May be easier to use a drop of white paint or pinch some of the wife's nail varnish.
You will need to rev the bike to 4000+ to set the maximum advance point, then lock the distributor up.
Hope this helps.

Nick

Re: Help strobe timing 1960 w/ distr. & Boyer ign? [Re: The Momes of Wrath] #786430 10/07/19 4:18 am
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Gordo in Comox Online Content
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I am not familiar with the Distributor Boyer setup but is sounds as if you are able to make a rough starting setup. You could leave the degree wheel and pointer on the timing side while you prepare the rotor on the primary side. I have in the past made a sheet metal pointer and attached it with one of the stator nuts. With this pointer in place use your degree wheel you already have on the timing side to set the engine to 38 degree BTDC. At this point you just need to then scribe a line on the rotor to match the tip of the tin pointer. My later factory manual only shows 38 degrees so the early engines might be different.

Take off the degree wheel and pointer on the timing side and close it up. With the primary cover off you should be able to strobe the engine and make fine adjustments rotating the Dist. As far as rpm goes there is a point where the Boyer stops advancing and it is at that point your line and pointer will be aligned and steady.

Gordo


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Re: Help strobe timing 1960 w/ distr. & Boyer ign? [Re: NickL] #786468 10/07/19 2:51 pm
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The Momes of Wrath Offline OP
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Originally Posted by NickL

Always rotate the engine in it's running direction or you may find backlash in the timing gears
will give you an odd result.


I'm actually reading in more than one place to turn past 38 and then BACK to it, but I think you're right. I wonder if that came from someone turning the engine with a different nut. If you imagine the crank's teeth having a forward side driving the "back" side of the driven gears, that's the normal takeup for lash... if you're rotating using a driven gear, I think it would reverse that, so you'd need to turn past 38, then go backward so the "back" edge of the other gear goes back into contact with the "forward" side of the crank's teeth as if running normally.

Re: Help strobe timing 1960 w/ distr. & Boyer ign? [Re: The Momes of Wrath] #786508 10/07/19 10:42 pm
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NickL Offline
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Yes, that may relate to a driven point, i was talking about the actual crank nut on the primary side.

Re: Help strobe timing 1960 w/ distr. & Boyer ign? [Re: The Momes of Wrath] #786524 10/08/19 1:22 am
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Ginge Offline
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You can still rotate the distributor though.

Can’t you just get a rough start up position ( Boyer in place under distributor cap) then tune using the distributor rotation on the clamp?

I’ve done it on my 3TA on points on the road with whatever spanner locks down the clamp. The Boyer should be easier than points. Wasted spark means only one adjustment once the thing is running.


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