Leak Down tester kits for the Yamaha TZ125 4JT bikes can now be purchased via my online store.
The kit will fit all Yamaha Tz125 1994 - 1997 models. Most probably it will suit later TZ125 models as well though I haven't verified this yet.
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 blank plug. Pump the engine up to 5PSI and wait for 5 minutes. If there is no pressure drop at all or if it's less than 0.5psi, then the test is successful and the engine is assembled correct. If there is a pressure drop of more than 0.5psi, then fill the spray bottle with soapy water to find the leak and correct the issue.