Interesting thread.
I recently bored a set of NS400 carbs for a mate, but haven't got around to putting them back together yet. Got to get Andy's carbs put back together first or I'll be in trouble. Shhhh.......don't tell Andy
I thought about the MC21 carbs being used instead but seeing as matey wasn't too bothered I never looked too deeply into modifying the carb insulators. The NS carbs are tiny by comparison.
I got the job basically because this guy had seen the Jha conversion and had asked for details. Just bored out stock new carbs was the answer so nothing fancy, and seeing as he had three sets of carbs he donated on to the cause.
Let us all know how it goes with the 21 carbs. Gotta be better than those piddly little standard things.
Anyone thought of making, or done a big bore 400?