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Re: Leak testing

Posted: Mon Nov 23, 2015 11:48 pm
by eden
many leak around the mag gasket too, often the air escapes through the mag studs, most leak at the exhaust gasket and many leak on the inlet. They all leak if you just use bare gaskets, that's for sure!

Re: Leak testing

Posted: Tue Nov 24, 2015 12:24 am
by alanscottj
eden wrote:many leak around the mag gasket too, often the air escapes through the mag studs, most leak at the exhaust gasket and many leak on the inlet. They all leak if you just use bare gaskets, that's for sure!
Checked all gasket seals, I have used sealant and I can't find any leaks, however I have found two leaks on my tester but none on my engine! Will get the tester sealed up tomorrow and try again :D

Re: Leak testing

Posted: Tue Nov 24, 2015 11:21 pm
by alanscottj
Sorted the leaks on my tester, but, the needle hardly moves but over a few minutes it loses 1 psi (from 6-5) it then settles and hardly moves at all, but it does drop and settles around 3psu. I can't find any evidence whatsoever of a leak, I've sprayed the whole top end over and the mag housing, around the crank seal etc and no signs of a leak at all. What am I aiming for? 100% no movement of the dial or is there an accepted level of movement???

Many thanks as always :D

Re: Leak testing

Posted: Wed Nov 25, 2015 8:07 am
by eden
It will drop slightly to start with due to compressed air heating up, the reason its goes down a little is because the air cools to room temp which results in slightly less pressure :)

Re: Leak testing

Posted: Wed Nov 25, 2015 10:27 am
by alanscottj
eden wrote:It will drop slightly to start with due to compressed air heating up, the reason its goes down a little is because the air cools to room temp which results in slightly less pressure :)
So it settling at 3 would be ok? I suppose if there was a leak it would all go? After all, I can't find a leak anywhere so it should be good to go. Got rear hub bearing arriving today so can crack on with building it :D

Thanks all!!

Re: Leak testing

Posted: Wed Nov 25, 2015 9:52 pm
by coaster
alanscottj wrote:
eden wrote:It will drop slightly to start with due to compressed air heating up, the reason its goes down a little is because the air cools to room temp which results in slightly less pressure :)
So it settling at 3 would be ok? I suppose if there was a leak it would all go? After all, I can't find a leak anywhere so it should be good to go. Got rear hub bearing arriving today so can crack on with building it :D

Thanks all!!
Was the piston at the bottom of the stroke? If near the top perhaps it could be air leaking past the rings into the combustion chamber??

Re: Leak testing

Posted: Wed Nov 25, 2015 10:24 pm
by alanscottj
coaster wrote:
alanscottj wrote:
eden wrote:It will drop slightly to start with due to compressed air heating up, the reason its goes down a little is because the air cools to room temp which results in slightly less pressure :)
So it settling at 3 would be ok? I suppose if there was a leak it would all go? After all, I can't find a leak anywhere so it should be good to go. Got rear hub bearing arriving today so can crack on with building it :D

Thanks all!!
Was the piston at the bottom of the stroke? If near the top perhaps it could be air leaking past the rings into the combustion chamber??

I have found a leak behind the dished washer on the front sprocket, when I removed the front sprocket assembly the engine won't hold air at all, it must have been the washer itself doing the sealing, so it looks like the drive drive seal needs replacing?