Attilio, Sorry I didn't return to this site for a while, I hope this helps someone... You will need to remove the mag. The coil might not be bad. The coil output might be misdirected to ground as mine was. This is not an uncommon occurrence. The clamp bolts that hold the magneto in place and hold it...

I did compete twice last year in Intermediate. It's now Christmas 2019 and the proposed Known for the US IAC competition season has been released. The Intermediate is easier than last year (I don't care for it) and the Advanced has more 'Push' than I care for (at this time) The Yak is running fine. ...

Hi Jay; I haven't checked this site for a while. The first year I had my Yak-55M at Acro Camp, the instructors were very taken with the plane, but one of them warned me to stay away from the MT 3 blade, it would be a disappointment. So I elected to go with the Whirl Wind W-530 blades as I documented...

The missing pic:

Here is a pic of the coil firing through a piece of 8mm MSD brand spark plug wire that replaced the original. The spark easily jumps the 10 mm air gap when the drive end is turned by hand. The long piece of wire from the coil (in a previous pic) attached to the points, which were dirty. Once cleaned...

You can see the damaged insulating sleeve on the extension piece in the previous pic
This is how it goes together. The tab at the base of the coil is the contact for the P lead. Grounding this terminal shuts off the magneto.

Here is a pic of the mag with the coil and coil extension piece in 'exploded' layout

Last week I experienced a magneto failure during run-up...for departure to the Corvalis Corkcrew IAC contest. :cry: I flew Sportsman (poorly) in my RV-8. This weekend I worked on the Yak. Of course, I started by accidentally selecting the wrong mag to disassemble. I figured it must have been the one...

Thank you Neville. This week end I attended Akro amp @ Ephrata WA, I think it was put on by the Canadian IAC closest chapter. There were 4 unlimited World Competitors on the ground, giving radio instruction in rotation. Each attendee received three 15 minute lessons per day over 3 days. I still don'...

Yesterday I spent most of the day with the Yak & Dyna Vibe. I eventually ended up frustrated. The frame I made to hold the synchronizing light and the vibration transducer may be vibrating from propeller beat airflow or something... I tried several combinations of weights and locations, and chained ...