I think 80% is too risky, but it depends on currency which is used to keep savings. Nowadays there are a lot of inflation risks for fiat currencies, which makes savings a risky investment too, if money is kept in fiat. And also it's important what the investment program is, since it can be small but stable profit, and it can be something of a gambling type. If its "gambling-type", I'd never invest more than 40% of the savings (this is actually a bet, not an investment in this case)...
Right, if money is kept on fiat then you have to combat the inflation as well. So, you must do something for you to have it retain its value through investing. Well, 80% of your total savings that will be into investment is a lot but real investors understand the risk and this isn't really a problem to them. Instead of doing nothing about it and seeing its purchase power goes down thanks to inflation, they'll choose to take a risk and that's through investing in those investments and assets they know will be of greater value someday. And to give an idea, we all know it that Bitcoin is making a huge difference and it has proven that it's one of the best assets that we can have to fight inflation.