This is a pretty straightforward job, however on this occasion, it is
made a little more tricky simply because of the fact I am still waiting
for the wheel rims to come back. So for now, we will install the engine
without the rear wheel and put that on later.
Put the engine cones (1 pair) in to each side of the frames engine mount tube. Do not use grease on this point as the engine bolt is NOT supposed to rotate as the engine pivots in the frasme during normal use. The pivoting of the engine is allowed by the rubber inserts in the silent blocks that are pressed in to the engine mount brackets. There are different types of engine mount cones, so make sure yours are correct for your model. Notice the split in the cone. This goes upward at 12 o'clock.
Both cones, once inserted should be flush with the frame tube. To tighten the main engine bolt, you will require two 24mm nuts and two wavey washers. The original nuts were not nyloc. The ones I am using are nylocs, which are far better than original for this purpose and are unlikely to ever work loose.
With a helping hand, get the frame mounts on the engine lined up with the frame tube and push through the engine bolt. You should be able to do this by hand. If you need to hammer the engine bolt through, something is wrong or not lined up properly. When it is through, place a wavey washer and nut on each side.
Finger tighten the nuts so they are equal on both sides.
Then simply tighten one or the other, or both until tight, check they are evenly on the bolt and when satisfied, tighten to finish.