Prime?

I'm guessing this has been covered before, but I couldn't find it. I have a 1982 KZ550 LTD with the Teikei 22 carbs. I bought the bike after it had been sitting for a year. As my handle states, I'm not a mechanic, so I took the carbs off and took them to a local shop to have them cleaned and rebuilt. Put the carbs back on (I am staying with the stock airbox). Turned the petcock to PRI, set the choke, hit the button, after a a couple of cranks it started, All good, right? I switched the petcock to ON, it idled fine, but would die as soon as I gave it any throttle. After a little bit of playing with the throttle, I could keep it running but not well. I pulled up a picture of the carbs, and it showed a vacuum hose running from the carb to the petcock, I went back and looked at the pictures I took before I removed the carbs, and the hose appeared to not be going anywhere. Anyhoo, I hooked the hose to the petcock, didn't solve my problem. If I leave the petcock on PRI the bike runs fine. Is there any reason I can't just run the bike on PRI? As a little background, my other bike is a1981 KZ305 CSR, which is a much simpler machine. Any thoughts?

You can run it on Prime but be aware of two issues: 1) if the float valves don't seal properly you will have gas leaking out your carbs or possibly into the engine and 2) most petcock I see with Prime uses the reserve inlet to supply fuel. This means you will always be running on the reserve setting so you will have to pay close attention to your fuel level.

Later, Doug

Based on your description your fuel tank petcock vacuum diaphram is toast. I would recommend you buy the petcock rebuild kit and repair it so you don't have to run on prime. Doesn't cost very much and will give you double protection. I have filled my crankcase with gas before and it's no fun at all.

In my initial post I probably should have mentioned that I am new at working on bikes. That being said, it appears that I hooked up the vacuum line from the petcock to what should be a vent from the carb. It appears the vacuum "port" on the carb has been plugged. Is that normal? A problem? Also, if this helps, the bike is verrrry cold blooded. Even on a warm day it takes 10 minutes to get to the point where I can ride without it being on at least partially choked.

It sounds like your carb holder are probably leaking. Spray some carb cleaner at the holders and listen for a change in idle.

You have to connect a small hose (3/16", I think) from the #4 carb to the smaller pipe on the petcock. The #4 carb is the only one that has a dedicated pipe for the vacuum petcock vacuum line.

The two vent hoses should run up to the top of the airbox, but don't connect to anything.

The ports on the intake manifolds should all be capped, or if you have the emissions device, the two middle cylinders have vac lines connected to the emissions device.

You may have seen the photo on the TK22 website in my link. It describes each hose and where it connects to the carbs.

As Markovich said, it may be that the vacuum diaphragm (it's actually a dual diaphragm) is leaking, so someone plugged the port on #4 and went on prime only.

Riding on prime means you will have no reserve fuel. When it runs out, you're totally empty. (Like StreetfighterKZ said) I would get a petcock rebuild kit and see if you can replace the diaphragm or have someone replace it.

Meanwhile, you can check it yourself. Go to a pharmacy and get a large syringe (no needle), and connect it to the vac port on the petcock and pull it. It should take almost no effort to get the gas to flow. If you hold the syringe open, it should never draw air, thus the gas should always flow. If air leaks into the syringe, the gas will eventually stop flowing. This means you have a diaphragm leak (or the hose or syringe has a leak).

As Nickleo said, you may have other vacuum leaks, which would cause the extra coldbloodedness. If you have no vac leaks, you can modify the fast-idle adjustment screw so it can be accessed while the tank is in place. Adjusting that for various different temperatures makes the bike more rideable, sooner.