Leakdown test Q

Whitty21

Member
Apr 15, 2010
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Small town, ON, Canada
did the test and it lost 2.5psi from 7.5 in 5 minutes. Is this within the margine of error. I sprayed everything with soap and i am not seeing any bubbbles. What do you think? oh yeh i already sealed the reed cage with rtv already
 
well there is no "time limit" for this test it should either be instant drop or a nice steady needle. you do not have to time an airleak test idk where that was strated, pump it up to 5psi and watch it for oh say 1 minute at most. even if you have even a tiny airleak the gauge will drop kindof fast and you will notice it right away. if its what you are explaning a very slight drop over a period of time its probably not a super tight seal on the exhaust gasket/flange and you'll be fine as long as you see no bubbles at the main leaking points. (its hard to seal there even with aftermarket pipes) just remember the test should be instant meaning within 1 min or less.
hope this helps
 
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well it is barely noticeble in a minute, and when i rearanged the exhaust block off it changed a bit, that must be my problem thanks guys

no problem dude its hard to get a nice tight fit on that flange. now your jetting should be a breeze
 
I picked up an expantion plug for the exhaust. i'm hopin it works well. i'll let you guys know if i ever put this thing together.
 
well i have it all together and ran it down the driveway. Then it was to jetting. Ken told me to use a BR9ES plug, well this messed the jetting, the 310 was working with the BR8 plug, put the BR9 plug in, not even close. went down to a 290, still not close, i am sick of pulling jets for now plus the NHL season is starting now. I am outa normal jets, i have some dynojets to try, and if it dont work i guess i gotta wait........
 
I beg to differ with ya. Not saying that your exhaust isn't sealing correctly but- here is a direct quote from the Godfather- step 4. use a bicycle pump (not the aircompressor!) to pressurize the motor to 7psi and wait 5 minutes. If the airpressure goes down more than 1 psi or so you have an air leak. take an old windex type squirt bottle and put some dish soap and water in it and start squirting the motor, head gasket, base gasket, intake gasket.. and look fo bubbles. if you find bubbles you found your leak. if no bubbles, squirt the seam all the way around where the case halves come together. if still no leaks start taking things apart and checking the main bearing seals. simple. Here is the thread-http://www.blasterforum.com/do-yourself-20/build-use-leakdown-tester-10663/

Ya want to be sure you don't have any air leaks or disaster will happen.
 
wouldn't i see that with bubbles. but anyway, my jetting was dead on before i replaced the head, there are no bubbles around the reedcage that i rtv'd and the head is holding 155psi, i only had the head a reedcage off, shouldn't i be fine?
 
alright well i talked to ken and he said the br8 would be fine, so i put the 330 jet in and it was running fine, ripped around for 2 minutes and took the plug out to check it, thecore was still white and the end of the threas had a little whit on them, so i assume it is running lean...... sooooooo i guess a will make a new rubber gasket to block off the exhaust for the leakdown and i will see what happens i guess
 
for the exhaust, why dont you use a rubber plug that has a screw and expansion when you screw it in.
i will get some pictures of the set up I use.
but have you just thought that maybe you are just running lean becuase of your jetting?
 
well when it gets colder out, air becomes more dense, so you have to recheck for that.
like if your current jetting is for 90F and now it is 50F, you will be running lean.
 
oh, never buy those kits, always get jets that are for you carb. like if you have a PWK carbs, buys kiehin only jets.