did vaccuum check after top end rebuild

[bighvygsx]

redid topend and didnt touch bottom. my guy says it should hold 5 psi for like ten minutes. mine holds 5 psi for like 2 min. what does this mean? what happens if i run or break it in thisway. is there anyway to swell the seals?

[dsolie]

Re: did vaccuum check after top end rebuild

How fast is the leakdown? Does it instantly drop off to 1psi or so, or does it take the full 2 minutes to drop? Something is leaking.. Are you sure you plugged the motor right for the leakdown test?

[Technical Support]

Re: did vaccuum check after top end rebuild

It should hold psi for min of 3 min @6 to 8 psi. Spray soapy water around the case to find the leak.

[bighvygsx]

Re: did vaccuum check after top end rebuild

found leak. crank seal behind pto. what can i do to fix without tearing whole moter apart?

[dsolie]

Re: did vaccuum check after top end rebuild

Nothing.. You need to split the cases and replace or 3-bond the rear seal.

[bighvygsx]

Re: did vaccuum check after top end rebuild

3 bond? whats that? i heard you can put acetone on it to swell it. what will happen if i run it like it is?

[dsolie]

Re: did vaccuum check after top end rebuild

You "can" run lean in the rear cylinder and blow your motor