1.1 red- starter solenoid
pink- blinker flasher
blue- fuse box
1.2 fuse connectors
1.3 you can just replace the connector
http://vintageconnections.com/there are other websites too
1.4 my 1975 cb550 only needs 3 fuses. do you have a K or F. i think the F model had 4 fuses (i think)
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2.1 its actually not that complicated once you know what is going on.

2.2 the stock coils on these bikes are beasts. they dont go out. but on the rare occasion they do you just have to buy another used one or go down the full out electrical overhaul.
i would test it out first and see if work. (have all the electrical hooked up and take off a plug put an extra spark plug on it and hold it up to the engine and hit the starter and see if it sparks.)
the way i went was kept the coils cut the cables replaced it with a dyna solid copper core used the splicers to attach and replaced the spark plug caps

you can see the model # for the spark plug caps and spark plugs
replacing the whole points plate coils wires plugs. you a lot of people can chime in on this and head you down the dyna coil path. get ready to drop $300+
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3.1 answered
3.2 replacing the headlight is easy. just make sure u use a bulb that has a high and low beam.
personally keep the headlight bucket and get a 7" H4 conversion headlight. this eliminates the whole buying a new headlight thing and not you can just replace the bulb.
understand the bikes dont have the best charging system so make sure you use the motorcycle H4 bulbs and not the car H4 bulb like the 100/90 watt
people will probably chime in but i would thrown in a 35w HID H4 kit in the conversion. its more light and its only 35w so its super easy on the electrical system. stock bulbs are 50watt (i think)
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4.1 this all depends on how tall you are. im 5'9 175lb i like the clip on handle bars but you are a little hunched over. you would probably like clubmans and if you taller or lankier i heard the euro clubmans are good.
4.2 switching speedos and tachs are easy. just make sure the speedo 2240:60 tach 20:3 ratio
literally its just switching out the big metal cables and probably a red and black wire for the led on you new speedo and tach.
4.3 i dont really understand..... where are the wires cut? close to the exit by the connectors or close to the actual controls? you can just use any wire and if you can wield a soldering iron its pretty easy.
i took apart all my hand controls and re solders all the points.
used controls you can probably get them for 20-60 a piece
4.4 i dont know what your asking please elaborate more.
the master cylinder is up by the right hand control. a MC rebuild kit is just for the brake handle with the circle reservoir. you will need a long nose c clip pliers for the clip that holds everything in the MC (i hated doing mine)
honestly the best route to go and what i did was run a SS line from the MC all the way down to the metal pipe on the caliper and getting a brake switch banjo combo and placing that up into the MC and eliminating the tri splitter thing connected to your lower triple tree. the only thing that splitter is for is the brake switch to activate the brake light but with technology you can just completely ditch that.