ET: Engine (Twin) Checking the Cam timing on a twin

[Freebird]

30% is too high.

Indeed, this is the first time I have used my kit and just assumed that if the needle was in the green section (up to 40%) it's OK. However, having read up on it, clearly that is not the case.
My plan now is to strip the top end off both cylinders and recondition them as necessary, both gave similar leakdown readings.

 

[Monkeypants]

Indeed, this is the first time I have used my kit and just assumed that if the needle was in the green section (up to 40%) it's OK. However, having read up on it, clearly that is not the case.
My plan now is to strip the top end off both cylinders and recondition them as necessary, both gave similar leakdown readings.

There is a low pressure type leak down tester and a high pressure type.
It sounds like yours is the low pressure type. I have one of these and as you say, the green " good to go" section is up to 40%. A newly rebuilt engine tested about 20% and one with a lot of use was around 27 or 28 percent, still nicely in the green.
I borrowed a high pressure type leak down tester and iirc it showed about 5% on the engine that tested 27% on my low pressure leak down tester.

Glen

 

[ernie]

Is not standing on the kickstart for 10 secs a good enough leakdown test?

 

[erik]

It depends who is standing on the kickstart .With my 18 stones it is the perfect test! Regards Erik

 

[vibrac]

Is not standing on the kickstart for 10 secs a good enough leakdown test?

Starting a thread on breathers on this forum is also a good indication of bad leakdown