Hi my name is Ben and I bought a suzuki gt 185 1977 a month ago. if you want my opinion: Don´t buy the bike! I just bought my suzuki for $640 and it has everything original and in pretty good condition. That bike you´re talking about should be sold at max. $200 because the engine is obviously the most important thing on a bike! Suzuki used to make the best engines at that time so having a gt185 without a suzuki engine isn´t worth it. Replacing the engine is a very risky business so I wouldn´t consider buying this bike, thus either trying to find a suzuki gt 185 with its own original engine and restoring it into a good condition (like i´m doing) or else if its hard to find a suzuki gt 185 with original engine and parts, just search for a different bike from the same era (they are all pretty nice!). Remember these are old bikes so test them well before you make a purchase and if something doesn´t look/sound right, just leave. P.S: some parts are VERY difficult to find for the suzuki´s engine and as you said some are discontinued and you´d have to try to fit a part from a different bike which is also very risky!