a few things to check based on my personal experience with similar issues one r30s
-test pump on a bench, replaced my twice before i got a good one that wouldnt cut out
-remove cover on tank and check for rust flakes block fuel pick up 'cage', this caused issues on my 3rd r30, intermittant cutting out etc
-pull carb down and check for contaminants? havent owned a carbed r30 before so not sure if they typically give issues or
-make sure fresh fuel is being used and doesnt have water in tank
when it gives up the ghost and wont start it might pay to do the old check for air, fuel and spark test while its not starting, at least then you can narrow it down to fuel or spark (im sure its getting air). let us know how you get on