I'm thinking of using either LS Bell Hammer Gold or Yamanaka Special mixed with the respective engine oils for both 2-stroke and 4-stroke bikes for bore-up kit assembly. If there is any difference between 2-stroke and 4-stroke, please let me know.

We recommend YamanakaSpecial as a product. When using it at the time of engine assembly, it is not necessary to mix it with engine oil, but apply it directly to the metal. This can be done for both 2-stroke and 4-stroke engines. Please note that although there is no problem using it as an assembly oil, it cannot be used as an oil additive. It will cause clutch slippage problems.