It was a good weekend in Lincolnshire for Shelton, who now leads both the Mini GP and Pit Bikes championships.
In the first Mini GP race, Shelton, starting second on the grid, quickly pulled away into first place and held the position for half a lap before he was passed by Ash Barnes.
He was then struck by Rossi Brown, who crashed with one of the back-markers, but Shelton managed to carry on to claim first in class.
In the second Mini GP the Mansfield racer had a good start and led into the first corner before he was again overtaken by Barnes in the hairpin. Shelton held on to first in class, however.
In the opening Pit Bike event, he was fourth overall and led his class.
In the second race, he led the way and bagged the fastest lap with a time of 49.07secs.