SoCalBanshee Posted May 28, 2009 Report Share Posted May 28, 2009 I got a compression guage to check the compression after rebuilding the top end. It is one that you have to hold in place it does not screw in to the head. I am just not sure of the proceedure. do I only take 1 plug out at a time? do I have to seal the carbs or exhaust? The whole bike is back together and dont really want to take apart again. Quote Link to comment Share on other sites More sharing options...
kodie Posted May 28, 2009 Report Share Posted May 28, 2009 dont seal anything off. and I always do it one at a time just my preferance dunno if it matters to leave 1 plug in and check it or not but i do. and I've used the one you are talking about make sure you push down relativly hard while its being kicked or it won't be air tight. Quote Link to comment Share on other sites More sharing options...
SoCalBanshee Posted May 28, 2009 Author Report Share Posted May 28, 2009 thanks bro. someone told me that I should crack the throttle, does that sound right? Also do you normally kick it more than once or just one kick and that is it? Quote Link to comment Share on other sites More sharing options...
fastrthnu Posted May 28, 2009 Report Share Posted May 28, 2009 dude, take a plug out, have someone hold it in place, hold the throttle wide open and kick it over and over really fast as if running like 15 times with the coil disconnected. then the same other side. those hold in place ct`s are garbage, but as long as its sealed very well, it may work. Quote Link to comment Share on other sites More sharing options...
kawa110 Posted May 28, 2009 Report Share Posted May 28, 2009 i asked a similiar question today in the sticky thread "leakdown test" page 3.----- After i perorm leakdown tests on by shee and the 250 i want to do compression test i have the guage with the correct sparg plug thread hose, does anyone know the prpoer way to do the test/or know a link? I test the shee cylinders seperate yes? If the cyclinders areant seperate via the crank how will the comp test read per cylinder? and for the single cylinder how many times to turn it over? QUOTE (black sunshine @ May 27 2009, 02:02 PM) 6psi for 6 min is the recommended test.----leakdown test For compression, take out both plugs, turn ignition and gas off, hold the throttle wide open and kick until the gauge quits climbing. Quote (kawa110 @ May 27 2009) sounds good. 6psi for single cylinder?(all engines?, i have klx110 and eventually ill test it) Just kick until stops climbing 3 kicks or 12 kicks it wont matter? Quote Link to comment Share on other sites More sharing options...
TNTS355 Posted May 28, 2009 Report Share Posted May 28, 2009 I take one plug out, screw in compression tester. Kick until compression needle stops moving. I do not hold throttle open. If you buy a compression tester look for the adapter that has about the same length on the threads as the spark plug you are using. Quote Link to comment Share on other sites More sharing options...
RagunCajun Posted May 28, 2009 Report Share Posted May 28, 2009 Your suppose to hold it WOT when you kick the crap out of it for testing compression. Kick till it wont climb anymore. Then do the test 1 or two more times just incase it didnt seal good. Might give you a false reading that is too low. Quote Link to comment Share on other sites More sharing options...
RIPPEN Posted May 28, 2009 Report Share Posted May 28, 2009 I take one plug out, screw in compression tester. Kick until compression needle stops moving. I do not hold throttle open. If you buy a compression tester look for the adapter that has about the same length on the threads as the spark plug you are using. Simply not correct.. Except for the length of threads on the adapter part.. :thumbsup: Your suppose to hold it WOT when you kick the crap out of it for testing compression. Kick till it wont climb anymore. Then do the test 1 or two more times just incase it didnt seal good. Might give you a false reading that is too low. Cajun here has it.. Its important to have a correct tester. The one you describe I wouldn't trust anymore than throwing darts at a board with PSI readings on it. You could try but so little makes such a huge difference. Otherwise, take out BOTH plugs, your gonna be kickin like a mofo, this helps to let her turn over a bit easier.. Hold at WOT, this actually lets the air in to get the reading. Has to fight through that carb your gonna be looking at a leg that may feel as though its gonna fall off to get the # up. Like Cajun said, kick untill it stops. If I remember correct I think I usually have to kick 35-40+ to get there. RIPPEN Quote Link to comment Share on other sites More sharing options...
kawa110 Posted May 28, 2009 Report Share Posted May 28, 2009 i wonder if ther more kicks it takes is a indication of rings going? I cant wait to my 78 yz250 back in the frame and test it. I just replaced the top end and im highly curious to know what its got. LMAO Quote Link to comment Share on other sites More sharing options...
Pincushion Posted May 28, 2009 Report Share Posted May 28, 2009 Some good and bad info in here. -Get motor to operating temp -Remove plugs -Ground plug caps to motor as to not short your electrical system -Insert comp tester -hold throttle wide open and kick hard until reading does not climb anymore -repeat 3-4 times to verify correct reading -swap sides, repeat. Cold rings in a cold cylinder will give a different reading that warm rings in a warm cylinder. You want PSI at operating temp. Get a threaded comp tester with the threads the same depth as the spark plug. Good rule of thumb is to take a reading with a freshly broken-in top end. When that initial numbers drops 15% its time for another fresh top end. Quote Link to comment Share on other sites More sharing options...
2001Stroker Posted May 29, 2009 Report Share Posted May 29, 2009 You need one that screws into the plug hole. You have to grind it down to the same length as the spark plugs. Yes, you have to hold the throttle wide open. You're gonna have to kick it around 15-20 times to get a good reading. Quote Link to comment Share on other sites More sharing options...
kawa110 Posted May 29, 2009 Report Share Posted May 29, 2009 Some good and bad info in here. -Get motor to operating temp -Remove plugs -Ground plug caps to motor as to not short your electrical system -Insert comp tester -hold throttle wide open and kick hard until reading does not climb anymore -repeat 3-4 times to verify correct reading -swap sides, repeat. Cold rings in a cold cylinder will give a different reading that warm rings in a warm cylinder. You want PSI at operating temp. Get a threaded comp tester with the threads the same depth as the spark plug. Good rule of thumb is to take a reading with a freshly broken-in top end. When that initial numbers drops 15% its time for another fresh top end. Didnt know had to ground the plug boots. Could i just use a wire for each plug boot that has a alligator clip in each side and stuff one side in boot to clamp on lead then the other clip to the frame. (one wire for each boot)? Quote Link to comment Share on other sites More sharing options...
black sunshine Posted May 29, 2009 Report Share Posted May 29, 2009 correct me if I'm wrong but if the ignition is off I don't think it is an issue. Quote Link to comment Share on other sites More sharing options...
kawa110 Posted May 29, 2009 Report Share Posted May 29, 2009 correct me if I'm wrong but if the ignition is off I don't think it is an issue. I recently lost my key(more mad about losing the picture of my dog that just passed keychain that was with the key) and mad cuz i had to wire the bike until i get a new ignition and 2 keys.(need that spare) The red swith will also kill spark wont it?(my keyed igniton is wired) Quote Link to comment Share on other sites More sharing options...
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