sometimes a High performance clutch will just cause the bike to "clunk" into gear. I put a new clutch in my cb750 k5 not long ago and I used stock steels and fibers but barnett springs (I don't remember if I put an extra plate in there too). I have adjusted the clutch the best I can and it still slightly clunks into gear because the springs are a little too stiff at idle and the clutch drags slightly. I put these springs in because I overload my cb750 when I tour (my girlfriend + Me + 150lbs of gear is probably close to 500 lbs total, approx 100 lbs past the weight limit of the bike) and running at 70mph for hours at a time like this tends to take it's toll on the clutch (surprisingly enough I have yet to bottom out the bike running like this). The 78 bikes are one of the faster of the cb750s but also heavier than their predecessors. It is not uncommon to find aftermarket Heavy Duty clutch components in these bikes to extend the longevity of the stock clutch.
My 78 was clunking into gear for a while but I pulled it apart and found two of the plates sticking together (from sitting). After I'd adjusted it, it is about haflway between a snick and clunk (still sounds bulky but does not lurch like my 75). These bikes are quirky, once you adjust to the personality of your bike you will know what to expect and compensate for it. The only thing you can really do with wiring issues is to make sure all the contacts are clean and everything is adjusted properly (like rear brake switch for instance) and all connections are tight. I once went 50 miles without the front brakes lighting up the brake light because of a loose connection so it nver hurts to give your bike a through once over.
