Jet/screw depth consolidated - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Carbs and Fuel System
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post #1 of 8 (permalink) Old 05-16-2012, 12:02 AM Thread Starter
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Jet/screw depth consolidated

Hey, guys.

First, I know I'm not the first to say it, but I can't tell you how helpful this site has been to a non-mechanic Vulcan resurrector like me.

Mine is a 1985 VN700 my uncle gave to me when he "upgraded" to a Harley (no comment). Cosmetically it's in great shape, but sat in his garage for 10+ years w/o being started. So the carburetors were all varnished, the tank was rusty, the battery needed replacing, and some electrical connections needed cleaning, but I got it running in no small part thanks to this site and my Clymer's.

I've already taken apart and cleaned the carbs once w/ Yamalube Carburetor Cleaner and compressed air, but kept having them flood about 20 minutes after I would ride it. To the point that the spark plugs would need to be removed and the starter turned over to get the fuel out of the spark plug slots. This would only happen after actually riding it, not if I just let it idle at 1500-2000 rpm for 10-20 minutes on the center stand. I had also run two full bottles of SeaFoam through the tank with no relief. I assume it was a stuck float, but wasn't sure if maybe I had the jets and screws incorrectly seated. I don't even know if that would cause the flooding, but want to do everything I can to get it right this time.

So, I've just finished taking them apart again, and will replace all the gaskets this time (which actually looked fine to me the first time, but since I'm doing it again, figured I'd just replace them all.) There were some residual varnish flakes (not much), but the floats/float valves all looked good. I've seen scattered recommendations in these forums, but I'm mainly looking for a definitive answer to the proper number of turns for each of the jets and screws all in one post.

The bike has all the original equipment, no modifications have been done above stock parts.

Specifically, I need the number of turns back out for (numbers listed are from the blow-out in the manual):
1. Pilot Air Screw attached to the throttle adjust (I assume that just goes all the way in)-16016
2. Pilot Air Screw next to the vacuum nipple (supposed to have a plug on it, but mine were plug-free)-16014
3. Pilot (Slow?) Jet-92064
4. Main Jet-92063
5. Drain Screw (I assume all the way in)-92009

Any advice is greatly appreciated in advance. I also apologize if this already exists somewhere, but I couldn't find it.
-S
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post #2 of 8 (permalink) Old 05-16-2012, 06:56 AM
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All but #2 go all the way in I believe. That is set at 1-5/8 out from the factory, but we all reccomend 2-1/2 turns out.

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post #3 of 8 (permalink) Old 05-16-2012, 09:16 AM
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Welcome to the forum,

Yeah start with the air mixture/idle screw the one that should have been capped 2 1/2 turns out and work from there,

The flooding could be that you don't have the floats set correctly and it is allowing to much fuel through.
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post #4 of 8 (permalink) Old 05-16-2012, 10:34 AM
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Quote:
Originally Posted by Knifemaker View Post
All but #2 go all the way in I believe. That is set at 1-5/8 out from the factory, but we all reccomend 2-1/2 turns out.
X2

Any residual varnish flakes are bad, but shouldn't be causing the flooding issue. I would check the choke system and float level. Also, the be sure the needle-valves are in good condition and seating properly (do not let fuel pass). They can cause flooding even when float levels are OK.

Good luck,
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post #5 of 8 (permalink) Old 05-16-2012, 10:09 PM Thread Starter
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Thanks all for your quick input. I'll unscrew the recommended 2 1/2 turns on the Pilot Air screws and screw all the rest in completely.

When you say check that the floats are set correctly, you mean adjusting the float tang so the line on the float falls between the two marks on the chamber? I hadn't done that the first time, but have done it this time before putting everything back together per the instructions in Clymer's.

Also, how do I tell if the needle-valves are seating properly. I suppose you mean the valves attached to each float by the tang, right. Both of mine look smooth w/o any obvious divets or irregularities. Is there a way to test for fuel leakage before re-installing the carbs on the bike?

Again, thanks for any input in advance.
-S
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post #6 of 8 (permalink) Old 05-17-2012, 09:22 AM
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Put a hose on the fuel inlets and blow down the pipe with the carbs in there normal position air should pass through, turn the carbs over while blowing in pipe and the air should stop when the floats fall on to the valves,

You need to check the fuel level in the float bowls with the carbs on the bike down load the free Kwa vn750 manual and look at pages 11/12 in chapter 2 hope this helps..

Last edited by Swagman; 05-17-2012 at 09:30 AM.
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post #7 of 8 (permalink) Old 05-27-2012, 10:35 AM
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sorry to ask but how do you get the plugs out for the pilot air screw

1991 VN 750
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post #8 of 8 (permalink) Old 05-27-2012, 10:19 PM
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Quote:
Originally Posted by Mortagleus View Post
sorry to ask but how do you get the plugs out for the pilot air screw
Use a tiny drill bit to put a hole in it. Then use a pick/screw/etc. to pry it out. Be very careful drilling. You don't want to damage the screw underneath. It's best if you can set the bit very shallow, or put a stop on it to accomplish the same.

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2005 VN750 upwards of 14K (haven't looked lately)

Mods:
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