Q: Is it ok to make conference presentations on my research before the manuscript is submitted?

You can present your unpublished research at multiple conferences. As long as the research is not published, you have no restriction in presenting it elsewhere. However, you should avoid publishing the abstract as part of the conference proceedings. Although it is acceptable to develop a conference abstract into a full-fledged article and submit it to a journal, it could be a problem if you publish similar abstracts in multiple conference proceedings. Presenting the same research at different conferences is fine. However, make sure that the title of your presentation is slightly different. Additionally, don't use the same slides for multiple conferences. Ensure that you make a few changes each time you present. 

Recommended reading:

• Is it acceptable to publish a conference abstract and an article based on it in two different journals?
• Can a conference paper be submitted to a journal?
• Can we present a research paper in a symposium based on our published research work?