[BagzyTopic starterBerichten: 5]

Thanks again
We expected the decompression valve to seal (even when engine is not running) but alas it does not seal.
Yes, we could block/blank the hole/cylinder head with a gasket to leak test the rest of the engine…but that surely that defeats the object of achieving a pressure seal test…?
The aim is to pressure test the completed engine with a successful test and then leave the test proven engine assembled and fit to the bike.
The question we have is……by design, does the valve seal when the engine is running? but not necessarily when engine isn’t running?
Hope this make sense 🙂

[BagzyTopic starterBerichten: 5]

Yes, we are using the stem that Malossi supply with the kit. Why is there a different stem available for Malossi heads other than the stem Malossi supplies? Is there a need/requirement for an alternative? Many thanks for the link 😉

[BagzyTopic starterBerichten: 5]

Thanks Seven/Semmad
Yes the spring is strong enough. We have hit the valve to the valve seat and we’ve used grinding paste to lap in the valve also.
We build many lambretta/vespa engines and always perform a pressure leak test after assembly.
Air is escaping out through the decompression valve when engine not running, i guess we will just have to hope that the valve seats properly when the engine is running…..dunno,,?

Many thanks

[Gebruiker]

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