Fastest Lawnmower in the World
The previous lawnmower land speed record was 80.792mph set in the US - Mr Wales was recorded as reaching 86.069mph. His team are now due to return to the same spot on Sunday in a bid to break the 100mph barrier.
Any of the motorised grass cutters taking part must also be built primarily from lawnmower parts.
Mr Wales's grandfather was Sir Malcolm Campbell who broke the world land speed record, in a car, at the same venue in 1924.
American Bob Cleveland set the previous land speed record on a lawn-mower at Bonneville Salt Flats, Utah, and was present at Saturday's run in Wales.