I do not think Bitcoin will crash, however I do think Bitcoin Cash will crash like crazy when it first comes out. Yesterday I was watching trevonjb's livestream on YouTube and when he asked his viewers what they were going to do with their Bitcoin Cash, majority of his viewers said they were going to sell their Bitcoin Cash. Not a lot of people plan on holding it and we can assume that more people are going to sell it rather than buy it.
It is very possible that after Bitcoin Cash crashes that it will go on a pretty big bull run. I think the Bitcoin price won't be affected at all because the main focus will be Bitcoin Cash and not Bitcoin.
Thanks for reading and let me know your opinion on whats going to happen in the comments below