That motor mount direction:OS picture in Section 2-1 is wrong. You've got to have the shorter distance down, like the Webra diagram.

Spin the big black main gear counter-clockwise by hand. Does it make a metallic grinding noise? All you should hear is the tail rotor belt and feel the tail rotor spinning. If you hear anything metallic your engine is mounted too high. Per the crude drawing on 2-4 mine looked correct too but the drawing leaves a lot to be desired.

You said it was fine when you're flying but I thought the same thing till a more experienced pilot flew mine and pointed out the problem. He noticed that the main rotor wasn't freely spinning down on its own when he cut the throttle. I wouldn't have know any difference.

Shoot me an email and I'll send you a digital photo of my heli's clutch and motor mount. Perhaps a picture will help. [email protected]