Leak Down tester kits for the Honda Nsr250 bikes can now be purchased via my online store. The tool will fit the following models : MC18 MK2 MC21 (all) MC28 (all) The leak-down tester is an essential tool for any high performance two stroke engine. This kit is installed in place of your carburetor and by pressurizing the engine cases you can check for any air leakage due to worn mating surfaces, erratic torque values due to aged parts, worn crankshaft seals etc. It is a necessary evil that it will help prevent catastrophic damage to your engine and keep performance up. A very valuable tool for a two stroke engine, handmade with care. Directions of use: Testing can take place after a newly assembled engine to verify that everything is leak free, on a bike you just bought and you need to check crank seals condition etc. Place the tool in the carb manifold, seal the cylinder head with a normal spark plug and seal the exhaust flange with the included CNC exhaust