Jyapus are really rich in cultural heritage than any other community in Nepal and that is the fact.
In Nepal Bhasa (Newari), Jyapu word has been formed like this "Jya yaae fu" meaning very hardworking people.
There is a Jyapu Story Linked with the Rato Machindranath and Bhoto Jatra? Does somebody write that story?
I am writing a short Jyapu story linked to Rato Machindranath and Bhoto Jatra that my grandmother told
As we all know that the Rato Machindranath is a god of rain - Once upon a time, in Kingom of Nepal (then considered as Kathmandu valley), it did not rain for 12 years. All the tantrics, kings of valleys( kathmandu, Lalitpur and Bhaktapur) decided to go get Machindranath who then resided in Assam ( now a province of India). Then Jyappu "Lalita" helped those tantrics, kings of valleys to bring them in kathmandu valley. [I dont remember the story very well ... its fuzzy in my brain]. It is believed that Lalitpur got its name from Jyapu "Lalita" which later became Lalitpur meaning "residence of Lalit".
Once the Jyapu "Lalit" was working in a hot sun taking care of his land - while he was working, he lost his "Bhoto" ( a vest). The vest is a special vest awarded by the Nagraj during the time of his journey to bring Rato machhindra nath to the kathmandu valley. Vest is decorated with the diamonds. So, it is one of the precious vest. Somebody found the vest and turned in. During the vast congregation of the people to see Rato Machindranath, it was demonstrated in the crowed so that they can claim it. Since, then the tradition of BhotoJatra in Jawalakhel has become alive. <interesting>.
If somebody knows the story in detail, i would love to hear it. lklk
Where are the Maharjans come from? 
I think that they are the one who settle down in the Kathmandu since the Buddha's time 500 BC and the others came to mixture and became mutli society. After that They were selected as the king of the state (Maha-rajan: prince or great king) and later on changed the atmosphere of that time and began the war among the other ethnic groups and then various tribal people arrived in Kathmandu from Baisai India, for example Litchavi,Malla,Khas etc.