Compression issue or carb issue?

[icekillah]

its been a while since i posted here, i didn't see Cyber Poet so im guessing his Reign of more than you ever needed to know knowledgeable answers is over, shame shame. anyhow i put on a set of used carbs (came from another bike) now my 96 kat 600 likes to idle at 3k rpm then cut off. i just did a compression test (with carbs on) and i got 180psi on all cylinders is this too high? i did that test because the mercury in my motion pro was only jumping up and inch or so (last carb sync i did mercury was moving at least 6 inches. im doing more research on the compression test so i'll post more reliable results sometime tommorow. now i did not do a sync yet but cylindar 1 was way hot cylindar 2 was hot 3 & 4 were warm. will the mercury move up when i start syncing? (that dosen't sound right to me if anything cylindar 1's mercury should of shot up. anyhow new plugs go in tommorow

[kevin2502000]

http://katriders.com/vb/showthread.php?t=102355&highlight=cyber+poet+died

I doubt you have a compression issue.

[icekillah]

what a damn shame, he always seemed so cautious and grounded, im sure he is missed. i always seemed honored when he answered one of my "help" posts, anyhow i have a question about vaccum now im getting 180 psi (seems high but bike wasn't running for a while so i guess that there are some carbon deposits, that will hopefully burn off) but im getting close to nothing on my motion pro mercury reader is this normal for out of sync carbs? if i sync them will the levels start going up? just got new plugs and am planning on doing the job sometime today just wanted a quick response before diving into the job

[Wild-Bill]

Sync gauges are measuring vacuum at the carb throat, not compression in the cylinder. Different things although related. Good possibility you've got a vacuum leak somewhere so look for that. Are any of the carbs missing the little o-ring under the top caps? (The ones that seal off the sync ports.)

[icekillah]

ok so this is what i got as far as running cylindars

c1 burning hot
c2 pretty hot
c3 warm
c4 cold

this is with new plugs although i had the same response with the old ones that were in there, the airbox is off, the vacuum line going to the petcock valve is blocked off (doesn't seem to make a difference either way, i got the soapy water but don't know where exactally to spray it, the carbs are bottomed out to favor cylindar 3 and 4 but 1 and 2 are definetally the dominate pair. it seems to like the 3k range but comes down to a decent idle then dies, also there is no response from the throttle or a very late response. i set the floats to 16mm because it seemed anything lower would cause a overflow, could that be my issue? would that cause nill vacuum readings on my manometer and all the other carb problems?

[kevin2502000]

You must have a dirty pilot circuit on 3&4. When it runs decent at higher rpms your hitting the main jet.

[icekillah]

ok i checked the orings for the vacuum port.....there. but i believe i may have forgot to put on one of the rubber caps for the pilot jet upon reassembally could that cause 3 & 4 to not fire? time to take them off and clean them out again

[Wild-Bill]

Leaving off the rubber caps covering the pilot jets means that the idle circuit will try to pull from the top of the bowl rather than through the metered passage in the float armature.

Not sure what you plan on doing with the soapy water. You're looking for a spot (or several from the sound of it) where outside air is entering the intake from the side, rather than through the air filter/carbs/manifold boots. Generally, the advice is to use something combustible and see if you can find a spot where spraying the whatever causes the engine speed to increase momentarily. I've never had any luck with that. Instead, I've just spent a lot of time standing on my head with a flashlight, looking for anything that didn't look right.

[icekillah]

ok got vaccum back on the manometer! however im getting a leak on carb 1 after fully cleaning floats and needle, but i have not ran the bike so maybe the floats didn't get sucked into their "ports" which would change the float height, wouldn't it? anyhow these are frankenstein carbs(had to put it together, carbs 1 and 2 are from a different (same model) of carb.

ok so my question is there a vaccum circuit starting on carb 1 going to carb 4 where there is the vaccum line that connects to the petcock?

also when i do a sync is the vaccum/petcock line suppose to be blocked off? haynes says no but a certified mechanic told me yes

if i can get this bike up and running again i will gladly make a long overdue donation which dates back to the days of Katanaplanet (remember that one?) its great what you guys do on this site and i actually remember some of your names/avatars particularlly the "horny hippo", and of course arsenic had called me a squid on more than 1 occasion, you guys should all get medals

[Wild-Bill]

The vacuum line coming off the top/side of #4 is supposed to go to the back (inside) of the petcock. It turns on the fuel flow when you're in ON or RES. (PRI allows fuel flow without vacuum.) When you take the tank off and run the engine you DO need to block that line off. Otherwise you won't develop any vacuum at all on #4.

As for the flooding after cleaning the needles, hopefully you've just got a bit of junk in the sealing area that'll rinse out of there after you run the bike a bit. Otherwise, you'll have to pull the carbs again, clean out the needle seats and take a good, hard look at the needles. If you can see a ring around the black tips of the needles then they need to be replaced. (Check out carbkitscapitol.com)