Did my leak down test today and it dropped from 9 to 7 in 18 minutes. Does that sound good to you guys?
Leak down test.
- Thread starter blasterdemon7
- Start date
I like to see no drop at all in 15 minutes but 9-7 is a REALLY tiny leak.
Could you find anything with the soapy water? Intake and reed cage usually have TINY leaks...
Could you find anything with the soapy water? Intake and reed cage usually have TINY leaks...
Didn't find any at the reeds, base or head gasket. May have a very small one at the exhaust with my rigged up seal. Have not been able to get to my crank seals yet. If the results are not A+, then I'll go farther to check. I'm not trying to put my motor at risk.
is the engine in bike or out?
i did mine in the bike and it was a pita to check everything with soapy solution
helpful hint. windex works really good and you dont have to mix anything up
i did mine in the bike and it was a pita to check everything with soapy solution
helpful hint. windex works really good and you dont have to mix anything up
If you have a rigged up seal and suspect that, figure a better solution.
While 9-7 psi in 18 minutes is sealed for general purpose use, I like to see no drop.
Also, don't count out the leak tester itself. I made the mistake of assuming the leaktester flawless until I couldn't find a tiny leak ANYWHERE and I had the engine out with both side covers off. I was getting ready to split the cases to reseal the case halves when I deiced to check the tester by itself. I had a small leak in the schrader valve. I tightened it up and the leak stopped....
While 9-7 psi in 18 minutes is sealed for general purpose use, I like to see no drop.
Also, don't count out the leak tester itself. I made the mistake of assuming the leaktester flawless until I couldn't find a tiny leak ANYWHERE and I had the engine out with both side covers off. I was getting ready to split the cases to reseal the case halves when I deiced to check the tester by itself. I had a small leak in the schrader valve. I tightened it up and the leak stopped....
It's in the frame. When I get the time, I have to barrow a crank puller off of 86 notch and do a check on my seals. I'll just go all the way and replace the seals. I already have a new seal kit. I'll stand it up on the grab bar and check my case at the seems to be safe.
Blaner
Your Friendly South African Ambassador
I would fret over it too much or go to extraordinary lengths to stop a 2 PSI drop in nearly 20 minutes. For all intents and purposes, that's sealed.
You really only need to be worried about a leak if the pressure drops off quickly and then eventually reaches zero. If the leak is only 2 psi in 20 minutes and the leak slows down as it nears 7PSI, I would rock on!
You really only need to be worried about a leak if the pressure drops off quickly and then eventually reaches zero. If the leak is only 2 psi in 20 minutes and the leak slows down as it nears 7PSI, I would rock on!
Blaner
Your Friendly South African Ambassador
beat me to itI was think about the crank seals and looking at them. The crank seals have the angled lip that rides on the crank. It faces out ward. Almost like a one way flapper seal. The vacuum in the crank case would pull on the seal and make a tighter seal do to the designe. I still think the standard test performed now is a good indacater but may need a little adjusting when it comes to judging the condition of the seals. It's still a great test to find leaks at other places then the seals. Just a thought that needs more thinking.lol.
They're double lipped seals. One lip points outward to seal during vacuum, one lips turns in to fight pressure...
During engine operation the pressure inside the crankcase swings wildly from vacuum to positive pressure. The seals have to be able to fight both. The trouble with a vacuum test is that instead of forming bubbles on the outside (where you can see it), it would form bubbles on the inside after it sucked the soapy solution through the seal and into your crankcase
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During engine operation the pressure inside the crankcase swings wildly from vacuum to positive pressure. The seals have to be able to fight both. The trouble with a vacuum test is that instead of forming bubbles on the outside (where you can see it), it would form bubbles on the inside after it sucked the soapy solution through the seal and into your crankcase
.Good point. Just something in my head that I wanted to throw out there to get some input. I dint look at it close enuff to see the double lip. The inner lip makes a big difference and blows my theory all to hell.lol.
I'm going to tell you the truth and it will probably make some others cringe to hear, but anything under about 4psi (out of 8) in 15 minutes, I would consider that sealed enough not to affet jetting. Think about how small a leak must be to only leak that small an amount in that long a time. Now think of the size of the carburetor throat (even at idle) it's HUGE in comparison. Unless your leak was SUPER easy to find and repair, I would rock on!
This is from the Ken O'Conner web site.(9 inches of vacuum . If it leaks down to less than 7 inches in a few minutes , you have a vacuum leak .)
and he has also told me numerous times to not go as high as 9 or 10, only around 7 psi using the positive pressure method, or risk blowing the seals out from the test, the crankcase area does not build that much pressure during normal operation
yours passed the leak test, now can we please hear this thing running already ????
we've been waiting so long an assdyno report may be the event of the year
yours passed the leak test, now can we please hear this thing running already ????
we've been waiting so long an assdyno report may be the event of the year
