I had a Efe at the back end of the eighties, I also wanted to gain more power, but as is nearly always the way my pockets were empty. So my idea was to increase power trying to use stock Suzuki parts as it would be cheaper than aftermarket parts. Most of the guys that were running Efe`s went with big bore kits from the states, which meant that there were loads of standard Suzuki pistons around, which are forged good for turbo`s The only work I did was replace valve guides and seals, heavy duty cam chain , slotted cam sprockets, heavy duty cylinder studs + nuts, two standard base gaskets and a 80thou spacer to lower compression. Also replaced the oil pump gear for that off a Gsx 750 et to give more oil pressure and straight cut gears to crankshaft and clutch basket I managed to buy a used Ray Jay turbo from a guy at Santa pod, replaced the bearings and fitted a new super shorty SS carb result 235 bhp at rear wheel. Never had the chance to run it at Santa pod but was loads of fun on the road.