Air suction system?

I have tried searching everywhere for info on this, to no avail.

My kz1000 has an air suction system located between cylinders 2 & 3. Kind of like a reverse EGR, it links the intake and exhaust. My problem is that whoever owned it before me, bypassed the system, and put duct tape over the intake hole. The valve is not there at all.

I am having trouble idling and starting. Could this be the cause? If so, where can I find the valve? I have looked everyhere.

It's not likely that the two are related unless the previous mods are now leaking air. I'd be looking for leaks downstream of the carbs first.
Good luck
KZCSI

Only thing downstream of the carbs is the rubber sealers between the carb and cylinder head. While yes, they may be leaking, I have to hold my throttle open a bit to keep it running. It will not idle, and is very erratic, Leaking rubbers wouldnt cause erratic running, would they? ( I am NOT an expert)

At the top of each tech section, there is a sticky note suggesting that thread authors include their bike's year/model and perhaps their location in their signature.

It is pretty hard to answer tech questions without knowing what bike is being referred to. Thanks.

1981 kz1000 K1LTD

Great. The way the emissions system works is that two carbs tee off their vacuum fittings. The 1 & 4 carbs are used. From the tee, a hose goes to a vacuum switch which opens the reed valves in your valve cover. I think there is a hose that also carries grunge to the airbox. If the emissions system is not used:

1. plug the openings in the valve cover with black permatex OR use one of the hoses to connect the TWO openings over the reed valves. Leave the reed valves in place as they have sealing gaskets so the valve cover doesn't leak
2. Remove the vacuum switch which is a brass colored cannister if it is still hanging under the bike as well as the other big hose which connects the emissions system to the airbox.
3. Remove the vacuum lines and tee from the carburetors and use 7/16" vacuum plugs on the vacuum ports on your BS34 carbs. Take a quick look at the #3 carb and be sure it has a vacuum plug on it as well. Make sure it isn't cracked.
4. Make sure the vacuum hose on the #2 carb is securely connected to the vacuum diaphragm fitting on your petcock and there are no leaks. ANY leaks in any of the vacuum fittings or plugs will cause idle issues (idle will be too high and won't settle when throttle closed).

This will take care of your emission related concerns. The problem though, is starting and idling. Do you have the factory airbox/filter on your bike? The emissions related stuff; at least the vacuum ports not being plugged or connected properly WILL cause idling/starting issues but so will other things. First verify that your emissions stuff is properly removed or connected and then we can move on to other potential issues affecting your bike's performance. Also, please describe why your bike doesn't idle as it should and when you say "starting problems", does this mean hard starting?

I have checked all the vacuum tubing, it is all intact.

When I say starting problems, I mean it is inconsistent. The idle is terrible, I have to hold the throttle open to keep it running. But as far as starting, sometimes it fires alomst instantly, other times it takes a few seconds of cranking.

It never starts with the throttle closed. I have to open it about 1/4 to get it to fire. Pilot jets are clear.

Is the OEM airbox/filter on the bike?

You start the bike with no choke with the throttle partially open or is this WITH the choke?

When you say bad idle, does this mean when starting the bike and the bike is cold OR does it mean after the bike is warmed?

Also, you had mentioned the emission system was partially modified? If so, the #1, #3 and #4 vacuum ports must be capped. Are any of these hoses that are present just hanging there or are they connected. If the emission stuff isn't working, best to remove it, plug the holes on the valve cover and cap them with vacuum caps.

Post edited by: wiredgeorge, at: 2006/08/07 15:09

All the vacuum holes are plugged, everything is capped off.

The choke is out when I start it.

The OEM airbox and filter were on. The filter was a little dirty, it is drying outside right now.

Idle is bad both cold and warm.

I appreciate the help, thanks.

I really wish I could help more but I have no idea what is meant by "BAD". Unless you get a bit more specific, I can't really guess what the problem might be.

By bad I mean non-existent. I have to hold the throttle open still, as I stated before. I bought some silicone, I am going to try that on the manifold rubber tonight.