More than likely the carb needs cleaning, just remember where the air/fuel mixture is set at if you take it out.
I wouldn't buy a lift, I would take the rear 400 shocks and move them up front and buy some used 450 rear shocks off ebay or where ever for the rear of your 400. This will give you some lift without maxing the supension out and keeping the soft ride of the 400.
I wouldn't buy a lift, I would take the rear 400 shocks and move them up front and buy some used 450 rear shocks off ebay or where ever for the rear of your 400. This will give you some lift without maxing the supension out and keeping the soft ride of the 400.