The previous two answerers seem to be unfamiliar with this use of "would". Here's what it actually means: If you look in any dictionary for the uses of the modal verb 'will', you'll find the example "My car won't start", or something very similar. This use of the modal verb 'will' is related to the orginal Germanic meaning of "will" meaning 'want [to]' or 'be willing [to]'. It means that there is some kind of technical problem, and the car refuses to start. Your sentence "His motorbike would not start" is simply the past tense of "His motorbike won't start" - in other words, "His motorbike refused to start". Is there a difference between 'would not start' and 'did not start'? No, not really. But I don't think that any native English speaker would say "did not start" in this context. For example: Why were you late for work this morning? My car .............. start. In the real world, a native speaker would always say "My car wouldn't start" rather than "My car didn't start" in this context. "Didn't" is OK, but "wouldn't" is much better. It expresses the idea of man versus machine, if you like. If you say "My car wouldn't start", we understand that you wanted it to start - there you were with the key in the ignition, anxious to get to work on time, and there was the car, stubbornly refusing to do what you wanted it to do. We can sense your frustration and anger. Why would anyone choose to use an inferior expression ( didn't start ) when we can use precisely the right expression (wouldn't start)?

Hey Misha, how are you? Is there a context for those sentences? Or did you just choose them at random? However, I may be able to provide you with enough information so you can understand the difference between those two sentences: 1) ''His motorcycle would not start.'' = in this case, the word ''would'' might either have been used to talk about something that happened in the past (usage of ''would not'') or to construct reported clauses/speech. As to the first option, it might convey the idea that ''there is no way his motorcycle could have started''; As to the second option, you may get this idea = ''(He told me that) his motorcycle would not start'' Here are some other examples that may help you: ''He asked if I would answer some questions.'' ''I felt confident that everything would be all right.'' ''They just would not believe what we told them.'' ''He would not come, even if I asked him to.'' 2) ''His motorcycle did not start.'' = in this case, there is no doubt the problem with his motorcycle (the running of this vehicle) is a finished event in the past, and so that is why the word ''did'' is used, which is the past tense form of ''do''. Hope that helps!!!

Thank you all for your answers. I really appreciate your efforts to help me. I found out a lot from your answers. Good luck with your language learning!

That's such an easy issue! Let me explain :) WOULD is an auxiliary verb and we use it for: - talk about the past - talk about the future in the past - express the conditional mood Case 1 ) "His motorcycle would not start." ----> We are using would as a kind of past tense of will or going to, which is common in reported speech eg. - She said that she would buy some eggs. ("I will buy some eggs.") - The candidate said that he wouldn't increase taxes. ("I won't increase taxes.") Case 2)"His motorcycle did not start." ----> We are using "did" so we are mantioning a past action which is started and finished in the past. That means there is NO RELATION in the PRESENT. Hope I helped you, and if you have any doubt you can read this article: https://www.englishclub.com/grammar/verbs-modal-would.htm Best, Luca