compression test???? Wet vs dry...

I got a push-on compression tester tonight (borrowed)...I am guessing these are not the best because it doesn't screw in but it is the one I have. This may be a stupid question but ... the reading on the gueage is indicated by a red line that taperes to a point... is the reading indicated by the point (at bottom of red line, not middle) or is it where the red line starts to taper... it is proabbly a 10 psi difference between the 2.
If it is the tapered point I got around 140 in each cylinder.. I ran the bike for a while (with carb #1 popping away..) and did the check again... got similar numbers.... I then added a squirt of oil and got about 10 more PSI....
I read earlier that if the pressure goes up significantly it is rings... if it doesn't it is valves.... is this correct? Sounds like a damned if you do, damned if you don't situation to me:laugh:
I plan to check the compression again once I know exactly how to read the guage... I will get accurate readings and re-post....
Still trying to find reason for popping in #1... Trying to avoid checking valves...for some reason i am a bit nervous to take off valve cover... etc....
Another question.... Is there any way I can do a leak down test myself with an air compressor or do I need specific tools????
Wish I was riding.... weather has been great here in western PA

I got around 140 in each cylinder.. I ran the bike for a while (with carb #1 popping away..) and did the check again... got similar numbers.... I then added a squirt of oil and got about 10 more PSI....

140 cold/dry and then 150 hot/oiled are really good numbers. If you only see a 10 psi increase when adding the oil, your rings are in pretty good shape.

You can get an accurate screw in comp gauge at Pep boys for about $20.

Yeah...I called this morning.... they even loan them out...(the guy said you have to buy it and just return it) I will probably get one tonight...
Is there an advantage to reading cold vs hot or should I do both?
I guess it is normal to have a ton of black smoke after running this test while the oil burns off, right?????
How about that leak down test? Is this something I can do at home or better left to a pro?
When checking valves do I need to get a new gasket for the valve cover or are these usually reusable?
Thanks for the help!!!!!

Actually, the 140 PSI for a 650 isn't great but is likely at the lower end of the service spec. Those numbers would be outstanding for a KZ900/KZ1000 but not a 650. Next, no one can tell you how to read the gauge you have. Problem with the press fit gauge is that you have to hold it snug in the plug hole and you have to have the throttle all the way open so I just take the carbs off so I don't have to fumble as much when turning the engine over with the starter button.

Did you check compression with the throttle all the way open or the carbs off? If not, the readings you got were not accurate. Next, the 10 PSI jump from dry to oiled means your rings are fine. I wouldn't bother with a leakdown test as the readings would have jumped WAY up... normally you will get a low reading if the rings are sealing... like 70 or 80 PSI and that will jump up to 150 PSI with oil in the cylinder temporarily making a seal.

The popping in #1 cylinder isn't due to compression loss or rings, etc. Popping is a mis-fire which is caused by excess air in the combustion chamber from a leak... exhaust gaskets, poor seal on the carb holder or a bad oring on the carb mixture screw or a bad/cracked vacuum cap, that sort of thing OR it can be poor combustion. Bad plug cap, wire, spark plug, etc.

I did the test with the throttle wide open....
I am going to get the screw-in tester tonight, just to make sure I have good numbers....
I have done the coil modification.... with a 12.8v battery reading I am getting low 11 at the coils... is this correct?
WG told me to get 110 & 17.5 jets...I had already ordered 117 and 20,I put them in, cleaned the carbs....I did not mess with the needle clip because i did not want to do a synch.... should I? It might already be on #4 for all I know...
I have new plugs.... I sprayed WD40 all over the carbs and mounts but got nothing...The bike will not idle without the choke on so I was holding the throttle open a little, would this throw the wd40 test off?????
I took the plugs out and checked for spark, they were sparking OK... i think ...I know there was a spark, just don't know if it was good....I could see it though....
At one point i did get a shock through the #1 plug wire when checking for spark.... could this cause the popping? The #1 plug was white when i removed it, i would think it would be black with deposits if the ignition was bad....The others had black deposits on them, I think because I did not listed to WG wirth the 110 & 17.5 jets.... (I will get the correct jets once I get #1 figured out) My wires go into the coils, not sure how I would change them...
I am still deturmined to be riding this fall but moral is taking a nose dive lately....



Wait... I just read WG's response again.... I guess I need to do 2 things that I have not done yet (at least).... Check the exhaust connection for leak and check the plug wires/cap....if I got shocked I must have some type of problem.....wouldn't the plug be black though????
As alredy stated above, I have no idea how I would change them though, they go right into the coil....
I appreciate everyone's time and advice....

WOW!!!! I feel pretty dumb....
When i got the bike the points needed replaced but the screws were rounded off...I drilled them out and replaced them but one of the holes was nicked and I could not get the screw to tighten.... well, this was the point for #1&4....I was thimnking abouut what Wired George said....I went through everything I did to test for leaks... looked at every wire.... finally after a while of going back and forth and also after a few beers I remembered the points screw and decided to check the it out again.... I took off the cover and watched as I turned the motor, the #1&4 point did not pivot at all... they stayed in contact the entire time,,,, no gap....i took off the old plate and replaced it with one I got a few monts ago (should have done it then but the bike was running OK)...
I took it out this morning and it is runnig like a little rocket!!!!!!:woohoo: This is the first time I ran it with the new jets and coil modification.... WHAT A DIFFERENCE and I will probably get better tha 30 mpg now....
Thanks so much for the help everyone!!!!