I am looking at the Honda Service manual "Brake System" chart.

It shows
"DOT 4" . It does not show how much fluid for a complete brake fluid
change ... I am trying to determine how much Amsoil DOT-4 fluid I want
to order.

Things not mentioned:
1. Hondas do not use Silicon based brake fluid. You can use mineral based (like at most auto parts stores. DO NOT mix the 2 types. they are incompatible.
2. I have found that if you get air in the line at the upper cylinder, sometimes air gets caught in the banjo bolt on the master cylinder. To clear this air bubble , it is necessary to crack it and squeeze the lever and close while squeezing it to get that last bubble out.

I use the harbor freight suction type that was mentioned by Honda_silver. It is a good unit for the money.

MaxB

I'd say the standard "DOT 4" will cover the composition. DOT 3, DOT4, and DOT 5.1 are all polyethylene Glycol based. DOT 5 is Silicon based.

I know it is wikipedia, but you have to start somewhere: http://en.wikipedia.org/wiki/DOT_4

What I meant is that the standard, which is DOT 4, defines the requirements for composition and performance. In the case of composition, the DOT 4 standard is similar to DOT 3 and DOT 5.1, but different from DOT 5.

The rest of the differences between the standards I do not know. I'm sure that data points such as boiling temps, viscosity, water absorbsion and many either things make up the DOT # standards.

Honda does specify DOT 4 for our SilverWings, but does not include the data Bill (honda_silver) is most interested in - how much is needed for a full flush.