Looking on the internet deeply has found these results:

by motorbike is the most popular phrase on the web.

by motorcycle 1393,000 results on the web	by motorbike 1412,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
You come all that way by motorcycle? They will go by the main road by motorcycle. And I thought you said you wanted to travel by motorcycle. As for crash helmets, these must now be worn by motorcycle drivers in all Member States. Compliance with this rule is still a cause of concern and campaigns on this issue are therefore still needed. Look, my boy Roger had a wad of cash... delivered to him by motorcycle messenger. He'll take you back by motorcycle. Two hours by motorcycle, but another world.	It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

by motorcycle

1393,000 results on the web

by motorbike

1412,000 results on the web

More popular!

You come all that way by motorcycle?
They will go by the main road by motorcycle.
And I thought you said you wanted to travel by motorcycle.
As for crash helmets, these must now be worn by motorcycle drivers in all Member States. Compliance with this rule is still a cause of concern and campaigns on this issue are therefore still needed.
Look, my boy Roger had a wad of cash... delivered to him by motorcycle messenger.
He'll take you back by motorcycle.
Two hours by motorcycle, but another world.

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.