MAC exhaust ON - with pics

[QBS]

Wheel bearing grease all over the new rubber and the area the motor slides into.

[The Prophet of Doom]

Are you using a metric o-ring.  Imperial ones are close, but NOT the same
With a new metric o-ring it is still a very tight fit.  You need to be more enthusiastic.  I used a rubber mallet and yes, lots of grease to get it in.

[Raj1988]

Does anyone know what size o-ring works for the nose?

[cvincer]

Lots of grease.

Make sure it's lined up properly

Push hard & 'wiggle' slightly.

If it does not go in, pull it out & turn the cog at the nose very slightly (it has to mesh with a cog inside the engine).

Try again.   If still no go, pull out turn cog ... etc, etc.