Import motorbike from Thailand to Vietnam

Hi.
I own a motorbike in Thailand and want to ride it to and register it in Vietnam.
Where can I get more info how to do it and how much it costs?
Thanks for help

Here is a reading list for you.  The first is specifically about imports from Thailand. 

https://www.expat.com/forum/viewtopic.php?id=395641https://www.expat.com/forum/viewtopic.php?id=317890https://www.expat.com/forum/viewtopic.php?id=285858https://www.expat.com/forum/viewtopic.php?id=68833

I have only done a very quick skim of these pages but they do not look optimistic.

Sell it there, buy here.

Ave yourself a lot of hassle and paperwork, sell it and buy again here.

Thanks guys for help. Yeah I know the best is to just sell it there but I have some free time and a trip on the bike would be nice.
What if I don't want to import the bike but just cross the border, do I get any stamps that  say when the bike entered to VN and how many days I have to leave?
Cars and bikes are allowed to enter to Vietnam right?
How is this checked?
Thanks