Yeah, it's primarily because I think it's been designed to be as light & compact as possible, so everything hangs off everything else with next to no space to get fingers in. (e.g. the air box also doubles as the support foor the front of the cowl, the chokle solenoid, the wiring loom clamp, the fuel connector mount etc etc, so when I want to take a carb out, I need to dismnatile the entire front of the engine. On the Yam - I took the lid off, undid 4 screws, and off popped the carbs. Having said that it was easier lifting the Merc (60) onto the transom than it was liffting the Merc (55) off! Another example is the Thermostat is integral to the exhaust manifoold cooling jacket, so if I need to replace that, I have to undo about 12 screws as oppsed to the usual 4 for a 'stat housing. (And that after having to remove a chunk of the throttle mechanism!)
Having said that, it's light and compact (as said before on a par with my 25Hp Suzi), so because of that I can live with a bit of servicing PITA once in a while. as 40 odd Kg is halfway to another passenger and once it;s been rebuilt I only plan to be servicing once a year - a lot less than I'll be using it!