It has 4. 4 plug wires means 4 cylinders. This is not correct. Many Honda V-Twins (2 cylinders) have 2 spark plugs per cylinder. The Honda Shadow Ace is one of those. It is a V-Twin.
You will need a 5/8 socket to remove the plugs from your 750 Honda motorcycle. A deep well socket is recommended.
1, 4, 2 and 3 as i remember it. --
You can use, for example, a Yuasa YTZ14S motorcycle battery.
You can buy parts for your motorcycle online. Oldbikebarn.com has replacement parts for a Honda CB 750, as does ebay.com. Also check out the classifieds in your local newspaper and any motorcycle shops in your area.
First production motorcycle with a hydraulic disk brake would be the Honda CB 750 in 1969
10w30 or 10w40 that is made for liquid clutch.
I might been biased here; The Honda 750- four, offcourse! Sure, it does not run as smoothly as the CB-500, but, who cares? ---