Thanks bill,l worked it out and its impossible the big pulley on top is 8.4 l think bottom one is 1/4 size top one laurent send me a photo image of both, scaled them thats how l come to the 1/4 size.So with that bottom one would be 2.1ins l wanted to half speed of my motor so half that pulley size 1.05 these sizes are tho o/d of the pulleys so the depth of "v" is approx1/2in each side take that away and you have a heap of alluminium cuttings and no bottom pulley if l reduced top 2, new belt. Object was to save money so its going l,m getting one l should have bought 1400 rev,sell the 2800 one its a nice little motor so should go no bother-thanks for your intrest-one cut