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Wanted: Parts


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I am in need of parts and tips.


I need a new or used muffler manifold for a 912 ULS, flight design specific construction. The female ball joints have become thin and brittle. During repair, one finally broke and we decided it's time to replace them. OR, if anyone knows a company that replaces the ball joints, that works too.


I have an air strut where the ball stud has broken. The strut is fine. The MM is not helping to describe what it is. I'll buy one off of someone, or if someone has the specs (I have no idea how to spec these), then I can get one ordered.


Anti-seize compound for spark plugs. I just want to see where people source them, and what everyone uses. We've been using a whitish silverish compound in very sparing amounts.


Anti-seize for exhaust ball joints. What do you guys use? I've heard various comparisons, right now we just use a silver type.

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The joints on each end of the muffler pipes are Rotax parts and not specific to FD. You can cut the old part off and weld the new on.

The female stainless steel socket welded on top of the muffler is part # 978-511,  male that inserts into female #978-521, the one that inserts into the engine exhaust port on the head is #978-252, the spring loops are #853-356 and the springs are #938-795. If you replace any springs replace them all..


You should be using copper anti-seize to lube these joints, the springs should have enough of a gap to see a tiny space between coils to have enough tension on them so the joint doesn't chatter with the exhaust pulsations and cause the joint to crack or the spring loops to excessively wear. If the springs need a little more tension just place a rod against the loop and smack it with a hammer to open the loop gap up some to add more tension to the springs. FD doesn't always have to right spring tension. Then with the gap slightly open on each spring when you apply the high temp silicone as called out for in the SB's and manuals then work that between the spring gaps. This will dampen the pulsation vibration.


The spark plug paste that Doug suggest works just fine or you can use this too.



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