Rd 350 leak down test fail

[Rgvnfla]

Hello fellow strokers,
Just completed,I thought, a rebuild of my RD and it failed the leak down.
I can hear and feel air coming out of the other cylinder exhaust port, pretty sure the case are sealed well with 3 bond. Maybe labyrinth seal ? Just thought I would ask for opinions before I split the cases again. Thanks in advance for any help

[Brad-Man]

Leakdown test involves sealing all intake and exhaust ports and seeing if crankcase holds pressure - labyrinth seal of no concern.

[85RZwade]

"Seal" is almost too strong a word for what a labyrinth seal does; impediment, or maybe resistor would be more accurate. Plug those exhaust ports up and try it again 

[Rgvnfla]

Oh I see, thank you gentlemen


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[kpke]

This should be applicable

[Rgvnfla]

Yes sir that's where my mistake was , didn't seal the other cylinder.
Thanks for the help


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[ajb]

Great, hope it goes well.  I just did a test on my RD400, phew, all good!

[Rgvnfla]

So leak down is behind me now , passed with flying colors.
Held 6 psi for 10 minutes without even a tenth psi of drop. In the frame it goes ! Thanks again for the heads up [emoji1690]


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[m in sc]

awesome.