I have a DA50 with the ignition sensor being set at the maximum counterclockwise position (when looking at the motor from the front). Not sure if it's right.
-What is the normal position?
-How do you adjust and verify that it's right?

If that's the way it arrived from the manufacturer, it's probably correct. There is no reason to change the manufacturers position unless the timing is wrong. Sensor position is determines the timing. All engines are not the same. See where I'm going? If it runs right, don't change it.

Full CCW is all the way retarded...Put it all way CW and tach it...Leave it where it runs best...If no difference CCW will cause the least heat...You can't possibly move it far enough to hurt anything...

This is the answer I was looking for (found it on another RC site). I'm posting it here so it could potentially help others with the same question.

The first thing you will want to do is take a fine line sharpie pen and draw a line at the leading edge of the magnet on the prop hub to the front of the hub. (as you look at the engine from the front that will be on the left side of the magnet. Then you need to take the spark plug out of the motor and put a small dowel rod inside the motor and just let it rest on top of the piston. Slowly rotate the motor over the direction that it runs, until the dowel comes all the way out of the plug hole and starts to go back in. Center the rotation of the hub by the dowel going in and out and this is top dead center. Now your mark you made on the hub on the leading edge of the magnet should be under the sensor. There is a small hash mark on the front of the sensor. Your mark should align with hash mark and this will be perfect.

This is basically what I heard from DA. Very easy to do. --qc

Here are some pixs.

Pic1: the location of the left side of the magnet - the line on the left
Pic2: align the left side of the magnet with the mark on the sensor body, while the piston is at TDC.

Note: the hash mark on the front of the body actually is aligned with the (middle of) metal pin on the bottom of the sensor body. My broken sensor does not have the hash mark casted. But a line can be drawn.

Cool !!!

You can't find TDC accurately with a dowel rod while the piston is rocking over TDC. The piston hardly moves at all when the crankshaft is rotated 15 degrees around TDC. You need to use a piston stop to block the piston when it is a good distance away from TDC, and combine this with a degree wheel. If you don't mind your timing off by 5 degrees, you can use the dowel method described above.

Diablo-RCU,

This is what I noticed: TDC is actually a range (relative small) of rotation. I simplied picked the middle point of it (roughly).

Can you tell us about the piston stop and degree wheel method? I assume those tools are obtainable locally? Do you know if DA sets the timing with this method?

--qc

I set the timing by looking at the piston through the exhaust port or the spark plug hole...You will find that a few degrees either way makes no difference...The dowel and degree wheel works well if you keep the dowel rod from moving...You can get a 10mm bolt at the hardware store...Screw it into the spark plug hole..Rotate the crank one way and mark the hub where the crank stops..Rotate it the other way and mark it again..TDC is exactly in between...you still need to know what number you want to use for full advance, and where the spark occurs relative to the sensor...Also do you want to use 28 or 30 degrees BTDC, or something else that someone says works better....Also how many degrees before TDC DA uses when setting up the igniton..Falkon is 2 degrees, C&H is 28 or 30, others may vary depending on the degrees of total advance the igntion is made for..
More trouble than its worth unless you just like to tinker...Read my post somewere near the beginning, it will tell you more about where it should be...The slots in the sensor won't let it go far enough either way to make much difference anyway...Best place is just past where it starts to show a slowdown in max rpm....Called "power timing" in the old days before we got all fancy with computers

According to DA, TDC is where the aligement should take place. There is no before-TDC setting for DA engines (at least for DA50).

cheers.

First, get a degree wheel or make one. You can download one for free, print it out and glue it to a wood disc. Make a pointer - I use a large paper clip attached to a cylinder fin with one of those big metal spring steel paper clips. Remove the muffler from the engine. Rotate crank so piston is at bottom of stroke. Insert a popsicle stick into the exhaust port and hold it up against the top of the port. Rotate the crank until it contacts the popsicle stick - that's your piston stop. Rotate the crank the other way until the piston again contacts the popsicle stick. Halfway between your two degree readings is BDC. Add 180 degrees to that and you have TDC. Accurate, and it costs you zip.

http://www.tavia.com/free_degree_wheel.html

Hmm,,, that's a good one

Cool! That is very much doable.