Most definitely buy before August 1 as we can see the prices are plummeting. Naturally, buy low sell high. This is a prime opportunity to buy, but you have to be fast.
In the past few hours, we have seen bitcoin's price rise from a 'low' 1800 USD to 2000 USD and rising.
Playing safe, I sell 70% of my btc, and wait and see after 1 august to buy again.
Honestly, why would you like to do this? The price is already on an increase and will likely be for the coming few months. It will probably hit the 4000$ mark and maybe even extend all the way up to the 5000$ mark if we are lucky.
These times are when speculation is at the worse. The general atmosphere is people expect something, so the minute the price drops everyone sells. A few people buy when there's a minor uptrend, and everyone gets caught up in it and starts buying.
Past few days the graph has been swinging wildly, the expectation is for it to do so until August first week.
I suggest sell, stop looking at the numbers for the next weeks - mind some other business

The reason is the market needs to stabilise - and 1800$ seems to be the right price, because that was the time when ether started to rise rapidly and took bitcoin with it. A lot value right now is just gas, and the volatility makes that obvious.
I completely agree with you, but I do not think that selling now is such a good idea. The bitcoin network cant just crash.... We will see it return to its normal operation after August 1.