The last years there is no more leaded gas for sale in the gas stations. In the seventies it used already to be the case in the USA and they have had a kit developed to assume the lubricating effect of the petrol by sprinkling the oil under the carburettor. The advantage of this kit is not only that you can drive without problems on unleaded gas with the 25-30H.P. engines, but the performance will improve considerably, because the cylinder heads will be greased. Therefore the valves, valves springs, piston and cylinder walls will be always cleaned and lubricated, which extends the lifetime of the engine and will also improve its performance. The use of oil will diminish. Sold per set for 1 engine.