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post #1 of 20 (permalink) Old 08-16-2011, 10:39 PM Thread Starter
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rich condition

so i need help from the forum
bought a kawasaki vulcan 750 2000 model, 11300 miles on it
Has been running rich since i bought it.
mods on it
unbaffled cobra exhaust, ear shave
was filling the crankcase up with oil when i bought it due to running so rich.
disassembled carbs to find that a float valve needle seat was pressed in incorrectly and was keeping the valve open. Corrected problem, cleaned thoroughly, reassembled, made absolute sure that all the diaphrams were sealed. Carbs were very clean on inside. Removed main jet and pilot jet and cleaned. there was another one in there but i wasnt sure how to remove it, didnt have a flat head slot or a hex head on it. did not remove that one and check it.
i am not currently running as rich as i was, but i am still running rich enough to foul plugs within an hour of running. with new plugs, runs like a bat outta ####! once they start to foul, wont idle good and loss of power.
I found that my needle valves are fluctuating at idle, not real far up and down but rapid up and down bounces. i am attatching a pic, the hole that is marked in the pic is spitting fuel out of it. I have already disassembled the carbs several time, checked comp, timing, cylinder leak down test, etc. I installed ear shave air cleaners but have done the coaster install yet. i have taken my reed valves off to look at them and they are so sooted up. I am a very seasoned mechanic with a background in professional motorsports. But i am totally stumped on this. I just pray that i am overlooking something, and by the way if anyone needs coaster plates, im gonna start milling out some custom ones soon, i made some for mine that are maltese crosses.
the petcock is operating properly. it was doing this with the stock air box setup. can some one tell me why my airflow through the barrel is not holding the slides at an even spot, and why fuel is coming out of the hole in the pic
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post #2 of 20 (permalink) Old 08-16-2011, 11:41 PM
If only it had 6th gear..
 
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Ok, forgive me if I'm asking overly basic stuff here. Not questioning your abilities but I'm curious how much the previous owner / mechanic had a hand in the stuff done to the bike...

Quote:
Originally Posted by jkmfab View Post
so i need help from the forum
bought a kawasaki vulcan 750 2000 model, 11300 miles on it
Has been running rich since i bought it.
mods on it
unbaffled cobra exhaust, ear shave
Did you do the mod's yourself? Wondering if we've got to back track over anything the previous owner may have done.

was filling the crankcase up with oil when i bought it due to running so rich.
You mean gas here right?

disassembled carbs to find that a float valve needle seat was pressed in incorrectly and was keeping the valve open. Corrected problem, cleaned thoroughly, reassembled, made absolute sure that all the diaphrams were sealed. Carbs were very clean on inside. Removed main jet and pilot jet and cleaned. there was another one in there but i wasnt sure how to remove it, didnt have a flat head slot or a hex head on it. did not remove that one and check it.
i am not currently running as rich as i was, but i am still running rich enough to foul plugs within an hour of running.
If PO did the ear shave, do you know what size pilot jets were installed?

with new plugs, runs like a bat outta ####! once they start to foul, wont idle good and loss of power.
So it fouls out the plugs in BOTH cylinders after riding around at different speeds? Or after idling? I'm thinking your jet sizes are too big for what you need and the area where you ride.

I found that my needle valves are fluctuating at idle, not real far up and down but rapid up and down bounces.
Were there washers under the heads of the needles? There's usually 2 with a re-jet and ear shave and but if too many are on there the needle might never sit all the way down when idling or in pilot jet operating range. What about the plastic needle retainers.. they intact? there even, lol?

i am attatching a pic, the hole that is marked in the pic is spitting fuel out of it.
Is it just that carb spitting or both? If only that one you may still have a float issue. If it's both then I'm back to the jet size question

I have already disassembled the carbs several time, checked comp, timing, cylinder leak down test, etc. I installed ear shave air cleaners but have done the coaster install yet. i have taken my reed valves off to look at them and they are so sooted up.
I wouldn't worry about the reeds, I think that's pretty normal. Mine are sooty too (now coastered) but never saw any ill effects.

I am a very seasoned mechanic with a background in professional motorsports. But i am totally stumped on this. I just pray that i am overlooking something, and by the way if anyone needs coaster plates, im gonna start milling out some custom ones soon, i made some for mine that are maltese crosses.
Wish I'd known that before. Just bought a couple, oh well. Would like to see a pic of them though. Bet you'd get some buyers. I'm might even though I have a set.

the petcock is operating properly. it was doing this with the stock air box setup. can some one tell me why my airflow through the barrel is not holding the slides at an even spot, and why fuel is coming out of the hole in the pic.
If you push the slides up by hand do they resist smoothly and come back down slowly? Or are they just kind of springy and slam back down. Something doesn't seem right about those needles bouncing. I know you made sure the diaphragm's are ok but if there's a tiny hole somewhere...
I really feel like you may need to run jets a size or two smaller, unless it's only at idle that your running rich, but from what you've said it seems like it's at all ranges and affecting both cylinders right? Hope I've helped you some. Out of curiosity what are your mixture screws set at?
dv

Last edited by DavesVulster; 08-17-2011 at 12:20 AM.
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post #3 of 20 (permalink) Old 08-17-2011, 06:06 AM
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Both needles are bouncing? Hmmm. Still seems like a vacuum leak somewhere. I've had this happen before, so let me search that distant memory and see what else I did to correct the problem.

A couple of additional comments/"seconds" on Dave's comments:
If you do the ear shave, you need to rejet - VoIP Doc has a nice write-up of the shave proc and the specs for the jets should be in there (42/142, I think). Also, 2 spacers under the needles (without the spacers, you'll be running rich).

That third jet doesn't come out, so you're fine with having just pulled the two out.

If you're spitting fuel, something's not aerosolizing correctly, which suggests a plugged passage. If you haven't yet, pull out the A/F screws completely (you'll have the screw, a tiny washer, and a tiny gasket) and clean out that passage.

I have a couple of spare carb bodies - if you want to try a different one to see if the problem is endemic to your carbs, give a shout.

C
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post #4 of 20 (permalink) Old 08-17-2011, 11:11 AM Thread Starter
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the exhaust and maybe some jet work was done before, i have put the shims on the needle when i did the ear shave. i am starting to think as well that the jet size is too large, or a blocked passage. i will get the jet numbers on it later tonight. i read an article last night on a condition that the keihin carb has that if it is too lean then it will foul the plugs and the plugs will be sooty but not wet. my plugs are getting sooty, but not wet. thank you all for the replies
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post #5 of 20 (permalink) Old 08-17-2011, 11:14 AM Thread Starter
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my mixture screws are currently at 1 3/4 out. i tried 2 out but ran too rich
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post #6 of 20 (permalink) Old 08-17-2011, 11:38 AM
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Quote:
Originally Posted by jkmfab View Post
my mixture screws are currently at 1 3/4 out. i tried 2 out but ran too rich
You may have the wrong size jets, 2 1/2 to 3 turns out is usually good. I suspect that your floats are adjusted poorly or are damaged. It sounds like the floats are dumping way too much fuel into the carb.

JM2001

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post #7 of 20 (permalink) Old 08-17-2011, 12:52 PM Thread Starter
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i bit the bullit right away and got a kawasaki fuel level tester, checked and double checked the floats, they are dead on
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post #8 of 20 (permalink) Old 08-17-2011, 12:54 PM Thread Starter
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i borrowed a kawasaki fuel level tester, checked and double checked the float levels, they are dead on
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post #9 of 20 (permalink) Old 08-17-2011, 03:57 PM Thread Starter
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just went and bought a factory jet kit, and a 142.5 jet kit and some new needle spacers, gonna play with the mixture when i get off of work
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post #10 of 20 (permalink) Old 08-17-2011, 05:37 PM
If only it had 6th gear..
 
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That's what I'm running. It screams thru the whole rpm range and is smooth when keeping her at a civilized pace. Hope your next post is a shout of joy.
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