Impossible timing

[plusvee]

Well guys, after solving the "small" issues, let's move on to something more complex. By placing the flywheel on the S line (not the letter S), the result is what you see in the photos. It is completely out of the position where it should be (and the plate is already all shifted to the left!). I tried disassembling the rotor and putting it back in place in the correct position (straightening the plate as well), but if I do that, it won't start. I then put the rotor back in the wrong position and the engine started. What else? The left muffler is bluer than the right one (the temperature is higher on the left cylinder). I also checked with the strobe light: I can't see any S, by increasing the engine RPM I can place the F line in the "correct position", but only at certain RPMs and I don't know which ones, because I don't have an exact measurement (if I increase RPM, the F rises above the line, if I decrease the RPM, the F is below the line). Finally, with the engine off, I tried to figure out where the point opening was on the flywheel: currently the opening is about 2.36 inches up above the F (I think that's a lot). Any thoughts on this? Am I in danger of damaging the engine if I drive with it like this? Two other things: I feel like the bike can go faster, but it doesn't. I don't have a "smooth" riding feel and from a standstill sometimes the muffler fires slightly. I currently maintain a fat carburetion to avoid seizure risks, but I don't like it (it's rather a forced choice); despite this, I managed to align the carburetors at idle (look at the photo) but when I accelerate, the vacuum gauge points out that they don't open the same way at higher rpm (the right carburetor opens less than the left one). I thank in advance anyone who wants to help me understand more.

[schrader7032]

I'm not sure I got all that, but I'm sure you realize that the magneto timing and the ignition timing are two separate things. The purpose of timing the magneto in the body notch to the point where the engine is at the S-mark, is to get the hottest best possible spark when you kick the engine for starting. Magnetos don't put out much energy at slow speeds which is kicking speed...proper alignment gets you to the "Abrisz" point. With the engine at the S-mark, you position the magneto rotor with the mark in the middle of the v-notch. Tighten things down. Don't touch the magneto body any more!

Next you work on static timing using the points and the S-mark. Make the necessary changes to the points gap and/or the points backing plate to get the engine to fire when the S-mark is in the window.

If you're concerned about the flywheel being in the wrong position, trying moving the engine around...plugs out...and use something soft like a pencil or chopstick in the plug hole. Move the engine until the chopstick moves all the way out. Moving the engine either side of this position, the chopstick will go back into the hole. Somewhere in the middle is top dead center. The OT mark should be pretty near the window. Hopefully that will ensure you have things set right.

[plusvee]

Thanks, Kurt.

I think I have both things out of place (magneto timing and ignition timing).
If I place the magnet rotor with the mark in the center of the V-notch (so in the correct position) it is as if the spark does not have enough power to start the engine (in fact the engine does not start). If I leave the mark not in the center of the V-notch, but moved to the left (wrong position as in the photo) the engine starts.

Regarding static timing: if I open the points, they are well beyond the S-notch.
Also, if I look for the top dead center with a pencil inserted in the spark plug hole, they are beyond the OT notch.

What I am wondering is: is it possible that it is a problem of worn timing gears (especially the aluminum one) that make it impossible to fix everything due to the fact that X turns of the ATU no longer correspond to exact one turn of the flywheel, thus producing these S, F and OT shifts? Thanks.

[Seek]

It looks like your flywheel is not in the right position. Nothing to do with the gears.

So, pull out the gearbox and the clutch. When you have removed the big bolt that fixes the flywheel. You can have a peek if the flywheel still sits on the woodruff key in the right position. I guess you will have to pull the flywheel and get everything fixed doen there.

In special tools you need three long M8x1 ( metric fine thread) with nuts an the special flywheel puller.

[schrader7032]

How far beyond the hole is the OT mark? How many holes in the flywheel...5? If there are 5, then the placement could be as much as 72 degrees off. That should be around 5.5 inches of travel on the circumference of the flywheel.

[Seek]

But, we are talking about a /2, aren't we? That one only has 1 big bolt, not five.

[schrader7032]

But, we are talking about a /2, aren't we? That one only has 1 big bolt, not five.

Yup, your right. I was looking at a fiche picture and thought I saw 5 holes. How then is the flywheel indexed to the crank? Is there a woodruff key? If there's only one way to put the flywheel on, how does it get off?

[plusvee]

Update:
I disassembled the magneto rotor again and tried to reposition the notch inside the V. Nothing, it doesn't work, the engine doesn't start. I then repositioned the rotor as in the photo (in the wrong position) the bike starts without any problems. I took the strobe light back and rechecked everything: now I can see the S (don't tell me how, it's a mystery to me) the S is slightly above the line, but it's fine (before I couldn't see it at all!). The F, on the other hand, I can now see it only after a much higher RPM than before (this is also a mystery to me), by "ear" I think around 4000/5000 RPM (before I see the F around 3000/3500 RPM), but it's my guess because I cannot measure it. Another "mystery": when I was with the strobe light I noticed a high spark difference between left and right, after running a few test miles and checking again all with the strobe light, the spark seems to have evened out on both sides. Don't ask me how, at this point we are no longer talking about mechanics, but quantum mechanics (you know Schrödinger's cat paradox? Well, that's what I mean ).


@Seek
Thank you.
I think it is as you say. At this point I think it is the slightly shifted flywheel that is not holding the notch inside the V, I will buy a Matra 311, a Matra 292 and try to look in there.

[Seek]

If the flywheel shifted it probably sheared off the woodruff key. That’s bad and should be corrected. A loose flywheel can badky damage everything.

[scottiesharpe]

How to set the timing:

Remove the spark plugs. Using a chop stick, or the like, in the spark plug hole. Rotate the motor and find piston Top Dead Center. Now observe the flywheel timing mark and sure you are at OT. If not -- you have problems and need to disassemble to find out what's going on.

If the TDC and OT line up, then proceed with aligning the magneto. Align the flywheel to "S". At this point one of the two mag rotor tick marks should line up in the V groove of the magneto bracket assembly. If it doesn't align, take the mag rotor off and align it.

Next up, set your timing so that the points open when the flywheel reaches "S".

From here I usually proceed to check for differential timing, but that is a complex issue outside the scope of this discussion.