Well, you might try looking under the services/motorbike rental section here on the site:

http://newhanoian.xemzi.com/venue/category/108/Motorbike-Rental#1

Or you could take some of the advice from the multiple other threads on this in Ask A.N.H.:

http://newhanoian.xemzi.com/aska/answers/qid/7

http://newhanoian.xemzi.com/aska/answers/qid/773

http://newhanoian.xemzi.com/aska/answers/qid/127

Just a word of advice for others who might be (relatively) new to using Ask A.N.H., posting to an older thread, no matter how far it was buried in the list when you found it, automatically brings it to the top of the list. If you're looking for more detail on a topic that's already been discussed, this is the most effective way to do it so that future information seekers have it all in a single thread, instead of scattered throughout multiple threads. You can search directly on the Ask A.N.H. page for your topic (to only get Ask A.N.H. Q&A results) or do a general site search which will also return some Ask A.N.H. entries.

Good Luck with your bike hunt April1.

Great info, alpha!
Thanks for all that!
I should do some research next time :)