Greetings from the UK

So...first of all, Hi from the UK, I live in the Peak District in an old Farmhouse. I've just bought a custom Kawasaki Trike - I've had various bikes, classic cars and trikes before, sadly Stage 4 cancer has meant I'm having to sell my last bike so a trike will make do instead. 
About that trike, On my registration document the engine number is KZ10AE005205 but the actual engine number is KZT10AE008027. Luckily your excellent Model Recognition 1982-1985 indicates it's most likely a 1982 K1100.  
I always like to service my bikes when I get them, so I'm thinking some new oil and maybe redex the engine. I did hear that fuel treatments like redex can damage the seals on older engines - what does everyone think? I'm going to put Shell Super Unleaded fuel in it as well - the 5% ethanol one rather the 10% ethanol - I'm not sure what the US equivalent is. 
Anyone have any advice for a 43 year old engine?
Photo enclosed

Al
 

Welcome from Canada.

Cool looking trike!
I would just change the oil and filter.
Do other maintenance as well, but I have no experience with engine flushes.

 

Hi Al,
Welcome to KZR !
How about some more about that trike. Was that a shaft model 1100 before it was converted? What sort of a rear end does it have?

I'm not familiar with redex so I'll not venture an opinion.
Regarding the fuel, I've believe that using alcoholic gasoline is fine when I'm out and about but not for any amount of storage time. Fortunately there are a couple of stations that offer non-ethanol premium in my town so a final fill up before home helps keep the stored alcohol content of the gas lower. 
Non-ethanol premium costs $5.35 a gallon here. Regular goes for about $3.40 per gallon.
Regards
Bill/KZQ
 

Hi and welcome from New Zealand, ex Derbyshire. Great trike, did a lot on a friend’s VW bike trike in the UK, learning cornering is a laugh 😂
Be aware of Ethanol fuel if the vehicle is stored as it can wreck the fuel system. I learned that the hard way as I left my 18 month old Suzuki GSXF1250 over winter, here in NZ,  tried to start it and no go. 
The fuel had wrecked the injection system, virtually destroyed the fuel tank and cost me a fortune to repair it. I thought it was rust initially but it was green sludge. 
Rich.

Welcome from germany, Al!
 Great Trike!
Yes, as the other members mentioned : beware of  10% ethanol gasoline, and if possible, the 5% also...these ethanol gasolines are hygroscopic, meat they will take water in your fuel ! result after longer periods of storrage is than a rusted tank, "gum-emulsions" in your carbs and a lot of work to clean that all!
Komplete Oil and filter change is a "must"!
Take care, and have sucess!

Welcome from Leicestershire - I don't see the "Redex" doing any harm (other brands might !!) Redex has been around for nearly 100 years, in the 50's and 60's it was on petrol station forecourts and a "shot of Redex" with every fill up was routine. You could also leave the Redex and use "fuel stabiliser" when it's going to be parked for any length of time.

This may be a UK only thing but all petrol at the fuel stations now have ethanol in them, you only have a choice of E5 or E10 (The number being the percentage of ethanol in the fuel). My Mitsuoka Viewt car (1995) and Bianchi Aquilotto Autocycle (1952) both ran fine on E5, the Bianchi occasionally needing some octane booster. 
I've put the Redex fuel cleaner in - Thanks Wookie58! (also, in the US you have Chevron Techron or BG 44K instead)
Going to take it for its first big run out tomorrow   will be interesting seeing what bits work properly and which ones don't...