68chevyc10355 Posted November 6, 2010 Report Share Posted November 6, 2010 I just did a leak down and it dropped from 6 psi to 5 psi in 2 minutes. Every little bit I could hear a little gurgle of air leaking, but am having a hard time pin pointing where it is coming from even using windex or soapy water. I know some of you guys will run yours even if it drops slightly, but didnt know if this was pushing the issue or not. So, do you guys think its safe to run or what would you do? Also, does anyone know what kind of pressure is in the crankcase while the motor is running. Thanks Quote Link to comment Share on other sites More sharing options...
tripledsracing Posted November 6, 2010 Report Share Posted November 6, 2010 I just did a leak down and it dropped from 6 psi to 5 psi in 2 minutes. Every little bit I could hear a little gurgle of air leaking, but am having a hard time pin pointing where it is coming from even using windex or soapy water. I know some of you guys will run yours even if it drops slightly, but didnt know if this was pushing the issue or not. So, do you guys think its safe to run or what would you do? Also, does anyone know what kind of pressure is in the crankcase while the motor is running. Thanks the rule of thumb is nothing less than 2 pounds in 2 minutes from 6 pounds..so yea run it.. Quote Link to comment Share on other sites More sharing options...
68chevyc10355 Posted November 6, 2010 Author Report Share Posted November 6, 2010 the rule of thumb is nothing less than 2 pounds in 2 minutes from 6 pounds..so yea run it.. ok thanks...do you mean dropping to 2 psi from 6 or dropping from 6 psi to 4 though Quote Link to comment Share on other sites More sharing options...
tripledsracing Posted November 6, 2010 Report Share Posted November 6, 2010 ok thanks...do you mean dropping to 2 psi from 6 or dropping from 6 psi to 4 though dropping from 6 psi to under 2 psi in 2min is bad..if yours only dropped to 5psi in 2min you are good to go.. Quote Link to comment Share on other sites More sharing options...
06specialedition Posted November 6, 2010 Report Share Posted November 6, 2010 dropping from 6 psi to under 2 psi in 2min is bad..if yours only dropped to 5psi in 2min you are good to go.. X2. Run that biotch Quote Link to comment Share on other sites More sharing options...
spurdy Posted November 8, 2010 Report Share Posted November 8, 2010 Just my 2 cents worth. I run anything that doesn't hold 6psi for 6 minutes period. The way I look at it is this. If it leaks a little now it isn't going to get any better. It is very likely that any leak will only get worse over time which will eventually lead to a lean condition. I am sure it will be fine today, but what about tomorrow? I am super picky about motor assembly, bearings, gaskets, all are cheap in the grand scheme of things and get replaced every time. It might be a pain in the ass but I have never had engine trouble due to an air leak or anything. Again, not saying the other guys are wrong, I am just of a differing opinion. SP Quote Link to comment Share on other sites More sharing options...
AKheathen Posted November 8, 2010 Report Share Posted November 8, 2010 i like to stick with 6psi for 6 min, and -1psi allowable. if you can hear it, you can find it...there is actually a lot of pressure in the case. did you lube the seals when you went together? seals only seal up when they have oil in the surfaces. is your leak-down set-up leaking? the shrade valve tight? use a piece of vacuum line in your ear as a stethoscope to hear where the air is coming out. trust me...you are asking this question because you want piece of mind.......and you're not gonna have it until you figure it out...and be thinking about it while you ride, which doesn't make for the most fun... Quote Link to comment Share on other sites More sharing options...
68chevyc10355 Posted November 8, 2010 Author Report Share Posted November 8, 2010 i like to stick with 6psi for 6 min, and -1psi allowable. if you can hear it, you can find it...there is actually a lot of pressure in the case. did you lube the seals when you went together? seals only seal up when they have oil in the surfaces. is your leak-down set-up leaking? the shrade valve tight? use a piece of vacuum line in your ear as a stethoscope to hear where the air is coming out. trust me...you are asking this question because you want piece of mind.......and you're not gonna have it until you figure it out...and be thinking about it while you ride, which doesn't make for the most fun... I have looked at it from both sides. I figured it would be just fine for now, but WHEN it gets worse, I don't want to have to wonder whether I will catch it in time before a cylinder goes down. Im gonna go with your advice because the whole reason I asked this was for piece of mind. I just want to go out and be able to ride it like I stole it and not half ass ride it because of worry. I only put new rings in and did not have the cases separated, though I guess the crank seals could have lost their seal. Guess Ill have to spend some quality time with the shee this weekend and see what I can figure out. Thanks for your input. Quote Link to comment Share on other sites More sharing options...
tripledsracing Posted November 9, 2010 Report Share Posted November 9, 2010 i guess k&t,titan racing dont know shit so listen to these guys and drive yourself nutts tryin to seal your motor up when its not nessessary!.. here read this topic it MAY help.. http://www.planetsand.com/forums/ubbthreads.php/topics/1058425#Post1058425 Quote Link to comment Share on other sites More sharing options...
68chevyc10355 Posted November 9, 2010 Author Report Share Posted November 9, 2010 i guess k&t,titan racing dont know shit so listen to these guys and drive yourself nutts tryin to seal your motor up when its not nessessary!.. here read this topic it MAY help.. http://www.planetsand.com/forums/ubbthreads.php/topics/1058425#Post1058425 I guess I dont know enough about how big of an air leak it takes before I have to start worrying about problems. I ride it often and therefore dont want to have to do a leakdown after every ride, if that makes a difference. Thats why I am worrying about if the problem will get worse and I may not catch it in time(typically does a small leak turn into a big one, and if so how long does it take to get to the point of worrying? Once again it leaks from 6 to 5 psi in 2 min). All I know is that I want to do the least amount possible and still be safe for now AND in the near future. Dont know if any of this makes a difference to everyone's opinions. How often do you guys do a compression test and leak down? Quote Link to comment Share on other sites More sharing options...
tripledsracing Posted November 9, 2010 Report Share Posted November 9, 2010 I guess I dont know enough about how big of an air leak it takes before I have to start worrying about problems. I ride it often and therefore dont want to have to do a leakdown after every ride, if that makes a difference. Thats why I am worrying about if the problem will get worse and I may not catch it in time(typically does a small leak turn into a big one, and if so how long does it take to get to the point of worrying? Once again it leaks from 6 to 5 psi in 2 min). All I know is that I want to do the least amount possible and still be safe for now AND in the near future. Dont know if any of this makes a difference to everyone's opinions. How often do you guys do a compression test and leak down? which i do agree to a POINT if you can find were the leak is then fix it if not and like i said it dont go below 2 pounds in 2min then run it!..heck ive ran a bike that dropped to 3 pounds in 2 min and ran it and it ran all year long w/ZERO probs.. when do i do a air leak test?..well when i hear my bike running different than normal and starts acting up then il check for air leak and comp..6 to 5 psi in 2 min is awsome i wish i could get all mine to do that.. Quote Link to comment Share on other sites More sharing options...
68chevyc10355 Posted November 9, 2010 Author Report Share Posted November 9, 2010 which i do agree to a POINT if you can find were the leak is then fix it if not and like i said it dont go below 2 pounds in 2min then run it!..heck ive ran a bike that dropped to 3 pounds in 2 min and ran it and it ran all year long w/ZERO probs.. when do i do a air leak test?..well when i hear my bike running different than normal and starts acting up then il check for air leak and comp..6 to 5 psi in 2 min is awsome i wish i could get all mine to do that.. A couple of months before I freshened up the topend it held 6 to 5 psi for 13 min. Its obviously dropped so I just wanted to get as much feedback as possible. But I guess the present leakdown could be worse due to something that got tore apart when I put new rings in such as the base gasket, crossover tube, carb boots or head. Quote Link to comment Share on other sites More sharing options...
spurdy Posted November 9, 2010 Report Share Posted November 9, 2010 A couple of months before I freshened up the topend it held 6 to 5 psi for 13 min. Its obviously dropped so I just wanted to get as much feedback as possible. But I guess the present leakdown could be worse due to something that got tore apart when I put new rings in such as the base gasket, crossover tube, carb boots or head. Most of my motors have held 6 psi for over 10 minutes. I haven't ever had a problem getting a motor to hold 6 psi for 6 minutes. It just isn't that difficult, therefore I'll spend the extra 30 minutes to gain my own peace of mind. SP Quote Link to comment Share on other sites More sharing options...
tedd1 Posted November 9, 2010 Report Share Posted November 9, 2010 ... I only put new rings in and did not have the cases separated, though I guess the crank seals could have lost their seal. Guess Ill have to spend some quality time with the shee this weekend and see what I can figure out. Thanks for your input. Can you see the crank seals when you do the leak down? Are you spraying some soapy water and looking for bubbles? Quote Link to comment Share on other sites More sharing options...
T_Shee Posted November 9, 2010 Report Share Posted November 9, 2010 Most of my motors have held 6 psi for over 10 minutes. I haven't ever had a problem getting a motor to hold 6 psi for 6 minutes. It just isn't that difficult, therefore I'll spend the extra 30 minutes to gain my own peace of mind. SP x2. did mine when got back from little sahara and got 6 lbs for 20 min. the only time ive dropped psi i have had a leak that i could find. as tedd said make sure you have both covers off and spray soapy water around seals and case mating surfaces. as well as around base gaskets, intakes, and your leak down tester itself. any air coming out will cause it to bubble like a bitch. i woldnt run it personally because it would drive me crazy but that is your call Quote Link to comment Share on other sites More sharing options...
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