Merlin, you normally don't need to crate a motorcycle unless one of the following conditions exist:
- You are worried about theft during the shipping and warehousing process, at either origin or destination.
- You plan to ship a lot of loose spares or baggage in the crate with the bike.
- The airline intends to charge you dimensional weight (cubic weight) rather than actual mass weight.
If none of the above conditions exist, just build a simple wooden pallet, like the one in the photo below, and strap the bike to it. The airline will then forklift the bike into a cargo container, or put it on a flat aluminium sheet (like a cookie sheet) that fits into the aircraft.