It depends on what state you are in. You either need to go to your local/state registration/transport center and get the info there or find it on one of the websites. There are PDF doccuments online with ADR requirements and required equipment for registering motorcycles in each state. In NSW i beleive you need blinkers no matter what age the bike is and when it was made, in other states it is usually not like that. The PE never had blinkers in 78 and was complianced like that so unless you live in a state that requires blinkers no matter what, then you don't need to fit them. Simply set the bike up as it was complianced in 1978. See what the Suzuki parts book shows the bike having, then go to your rego office and register it. You will usually need to take in the frame and engine number, old rego plate or previous rego label/disc/papers etc are handy if you have got them. If not just the bikes numbers will do. They will then probably tell you that you need to take bike to police station for an inspection. Normally this is just to check the numbers to make sure its not stolen and nothing to do with road worthiness. Then you take the police form to rego office and then they will rego the bike for you and away you go.
Some states offer Historic or club rego which is usually cheaper, but you need to be a member of an affiliated club, have a log book and often you are restricted to how many times a yr you can ride it, and often the bike has to be totally stock, with no modifications or customizations at all (which can be very restrictive). Being 175cc full normal rego wont be too much though.
All i would do is just make sure the bike meets requirements for your state and then just go to your rego place and go from there. They will tell you what needs to be done if the bike has dropped off the system and they cant find it on the computer if it has not been registered for many years.
As for equipment for old bikes, general rule of thumb/bare min is usually
-stop/tail light
- hi/lo beam headlight
- horn
- mirrors
- tyres that are legal for road use eg no MX tyres and anything that has NHS or not for highway use written on it
- chain guard - i am not 100% sure about this, see what the rules say. Many bikes are getting around without them though
- hi beam indicator - i am not 100% sure about this, see what the rules say. Many bikes are getting around without them though, its one of those items you could probably get away with out having if it is required. The PE's never had them when new and i restore heaps of vintage bikes that get registered that do not have them.
Generally if you are doing the right thing and not drawing attention to yourself you wont ever get pulled over anyway.
