Hello guys.
Got an NC30 and to cut a long story short I got it running sweetly with a chopped exhaust system and a blue flame pipe that came with the bike.
I then bought a standard system with the can welded onto the pipe.
Took the bike out and it is not pulling whatsoever, the power delivery is flat as anything and it simply does not pull away no matter how far I wring the throttle under load.
It's running on 4 cylinders with the right jets (pilot jets and mains (115/118)) and no restrictors in the inlet rubbers.
I was going to go for a Dyno run but I wanted to get some advice first?
Thanks.

1: Is the exhaust the only thing you changed?
2: When you say 'no power' what exactly do you mean? Is it missing at all? Did you touch the carbs at all when changing the exhaust?

Return the bike to the state when it ran well. Why did you change to the standard system?