This is the BRG big axle kit for the SV650 First Gen. We found that after building some motors with pretty good horse power, anything 90HP and above effected the stability of the bike on the exit of the corners. WeI use an Ajax or 600 rear axle make a couple of rear swing arm axle holders welded on to the stock swing arm. The bike handles better, but it will take a few races to really get a good feel for the difference.