Vacuum switch valve removal,,, Did I do it right?

Howyadoin,

Another productive day in the garage... I replaced the existing Splitfire plugs with the recommended NGKs, and nore importantly I ditched all the vacuum switch valve nonsense. Here's what I did, please tell me if I screwed up:

*Disconnected vacuum lines from VSV to carbs 1 and 4, capped vacuum ports on carbs. Carb 2 still has vacuum line to petcock.

*Disconnected long vacuum hose to airbox.

*Disconnected vacuum hoses at valve covers.

*Removed VSV assembly.

*Used piece of long hose to airbox to connect vacuum ports at valve covers to each other.

The throttle response off idle is improved, I hope this won't mess up anything else. BTW, the plugs looked good, but I replaced them anyway just so I know I did them and when.

So whaddyathink?

ya did good!! thats the typical way to block off those ports.just connect them together. id always run the correct ngk plugs.

This system is more trouble than it's worth. Many riders have removed it as it tends to burn valves after a while.

This was Kawasaki's way to reduce the exhaust emissions by introducing fresh air in the exhaust cycle. Since our older bikes don't need emission testing, I'd consider removing it on any similar bike.

You did it right, you should also notice less or no backfiring upon deaccelerattion. Cleans up the motor too!

Bluemeanie wrote:

You did it right, you should also notice less or no backfiring upon deaccelerattion. Cleans up the motor too!

I wish that were the case...

I took her for a ride and found the popping at idle and deceleration were really, really bad. That would indicate a lean mixture, right? There are a couple of variables here. One is that the hole in the front of the airbox where the hose from the VSV came in is still open, should I seal that off? Would that be enough to lean out the mixture?

Also, when I was fixing the rear brake light switch, I noticed a ~6mm hole in the side of the #4 carb that was packed solid full of dirt... :blink: I cleaned it out carefully, could this have caused a change in the mixture? Here's a pic with the hole in question circled in red:



Another couple of things... I changed the plugs, but they are the OEM NGKs, gapped to 0.8 mm, nothing funny there... And I added about 3 oz. of Seafoam to the half-full fuel tank.

Oh, and she's still idling high (2-3K) when she's been ridden for a while.

Arrggh... HELP!

Sorry but I didn't notice that the carbs were CV's. Most KZ's (with Mikuni carbs) that have the smog crap removed do have less popping as now the valve is NOT introducing air upon deacelleration. Is there anything in the hole? How are your carb holders? You may have the idle speed and mixture screws set for a cool motor at idle but once bike warms up any cracks may expand and seal themselves which will change everything. Try and spray some WD40 around holders when bike is cool and idling and note any differance in idle. These holders can be hard as a rock after many years.

Have these carbs ever been off the bike? Is everything been checked such as timing,tining chain,advance mechanism,and valve clearance.

You could try and turn the air screws in. They are locared in front of the carbs just above the carb boots. They might be covered with a metal plug. Remove the plug and screw them in 1/2 turn and see if that helps.

After the bike warms up turn the idle screw down.

That hole is a blank,right? Roy

"...the hose from the VSV came in is still open, should I seal that off? Would that be enough to lean out the mixture?"

Yes you should seal it up and yes it would allow more air flow. Enough to cause you problem, I don't know, but one thing I know for sure is that the air entering that open hole is NOT filtered.

Keep working at it, You'll get there.

KZCSI

Howyadoin,

I decided to check the pilot screws. I found the following:

Carb #1 - 5 full turns from seated
Carb #2 - 4 full turns from seated
Carb #3 - 6 full turns from seated
Carb #4 - 7 full turns from seated

I seated them all and set them all to 2.5 turns out, it seems to be running quite a bit richer, I'm getting a lot of gasoline smell in the exhaust. Does that make sense, does the mixture get richer the closer the screw is to the bottom? It's still not running smooth. #3 seems to be particularly bad, I think I'm getting some backfire up through the carb. I sprayed WD-40 around both sets of boots on each carb, both in front of and behind the carbs, and saw no change in idle.

My next steps are to check the mechanical advance and check valve clearance. If those are both OK, then it's time to pull the carbs and clean them, and replace all the carb boots while I've got them out. If the valve clearance is out of spec, I'll have to order up the lifter holder tool and some shims from Z1.

Another problem is that I don't know precisely what mods have been done to the engine other than the increased displacement (1000 to 1100cc); are the cams original, et cetera... The thing that really bugs me about that is if I decide to send the carbs off to someone like wiredgeorge and he rebuilds them and sets them up, I have no guarantee that I won't have to do more fiddling when I install them because of some unknown mod.

I'm beginning to see this as an off-season project I was hoping to get the bike stable for the remaining 6 weeks of riding season, then dig into the carbs, valve stuff and whatnot over the winter, but I can't even get her running well enough to feel comfortable or safe at this point... I'm not giving up yet though, dammit...


Thanks everybody for your help so far, I'm going to keep trying to get this right, both for myself and for anyone who finds this thread sometime down the road and learns from it. I'll let you all know what I find on the valve clearance and mechanical advance items.

You may still have to fiddle with it even after WG or you go through the carbs. As yu state it's not clear what has been done to it...

One thing I have learned is don't let the season rush you. I have made poor long term decisions trying to chase the season.

Keep up the good work!

When you turn the screws in you are basically restricting the air to the idle. Sounds like you are close to where you want to be. Roy

As far as the hole in the side of your carb that you cleaned the dirt out of goes, that is left over from the casting of the carb. it's the end of the fuel rail and does not connect to anything. I'll probably be taking the VSV off of my bike as soon as i get home today. the tube from the airbox is always falling off anyway.