If the bike shifts, the cases do not need to be split, but even if they did, its a really easy job on this bike. It sounds like a easy fix, clutch cable could be stretched, push rod worn, or actuator arm worn. Im not sure what the value on your bike is, but its gotta be more than a clapped out 84 R needing some lovin. Around here, you may be able to trade the bike for a 85-86R if its a good day. Dont get me wrong, the 84 R is a great machine, im building mine right now. You dont see as many around as the other years for some reason. Sport 3 wheelers are a lot harder to find in some places in Canada. I was at Haydays last fall, and there was a Canadian man who bought a 85 R and 85 350x for $3500. They were both in ROUGH just pulled out of a grove, and been sitting for 10 years shape. There are some guys up there that would kill for something sportier than a 200s, so I see why you are considering. Good luck if you do get the bike, and post up pics if you do!
THE 80's RAGE! Currently owns:
81, 85 Yamaha Tri Moto 125
83 Yamaha Tri Moto 200 x2
82,83 Yamaha Tri Moto 175 project
85 Yamaha Tri Z 250
84 Kawasaki Tecate 250
84 Honda ATC 70
85 Honda ATC 350X
84 Honda ATC 250R
(2) 84 Honda ATC 200x
82, 83 Honda ATC 185s
81 ATC 200
Lots of other parts and bikes