I have a Honda Shadow vt600. It ran perfectly until I welded my exhaust pipe and odometer to the bike. Now when I start it, it almost stops immediately. When I push the throttle it keeps going for a bit longer but it stops when I let the throttle go. My guess was that there went some ironshavings into my velocity stacks. I cleaned my carb and rejetted it to 145.5 for the main jet and 45 for the slow jet. Is it normal that it needs bigger jets when my exhaust pipes were welded a little bit longer or can I exclude this as a cause?