KZ400 simple carb question

Just a question. I replaced the carbs on my 1981 KZ305 with carbs off a 1978 KZ400. First of all, the reason was the carbs on my KZ305 were a mess and one of the choke flapper things was broke so one choke worked and one did not. I found a cheap one for a KZ400 on ebay and it runs awesome when it's running. Cold starts still suck (as it did on the original carbs) I always have to grind through a whole battery and then jump it to get it started, and the KZ400 carb has this orange hose coming from one side of the carb, which connects where I highlighted the picture, and it sucks air when turning the engine over. I stuck a screw in it for now to prevent it from sucking air and throwing off the carb fuel/air mixture. Where should that hose go????? And is there anything I can do with the cold start issue or is that just the way it is on old carbed bikes?



Post edited by: sorner, at: 2006/10/25 10:21

Post edited by: sorner, at: 2006/10/25 10:26

Post edited by: sorner, at: 2006/10/25 10:28

Those don't look like my KZ400 carbs, they look like the later ones - from '77 on. I think those models came with a vacuum petcock, and that might explain the hose...

they are from a 1978 KZ400

I have a '79 KZ400 Ltd and it has a vacuum-activated fuel petcock. I'm guessing that's where the other end of it goes.

Is it worth swapping out the petcock for this to hook up or just keep the original petcock and keep the hose blocked?

Post edited by: sorner, at: 2006/10/26 08:57

sorner wrote:

Is it swapping out the petcock for this to hook up or just keep the original petcock and keep the hose blocked?

So your 305 has a gravity petcock? If so, I'd just block the hose on the carb. Get one of those little vacuum plugs and cap it or something.

yeah, and the kz400 carbs i bought have a vacuum hose to hook up but I have nothing to hook it to, I have it blocked with a screw threaded into the end of the hose.