Lurching would be from jetting or from your drive chain being too loose. The latter is very common. Due to KTM's chain slider setup, excess chain slop isn't always immediately noticeable.
1986 Yamaha XT350
2005.5 KTM 950 Adventure
1991 BMW 318is turbo track car
1989 Chevrolet Caprice Classic Wagon, TBI 5.7, NV3500 5-speed, lowered, etc...bike hauler