Now a tuning issue

I recently pulled the carbs apart to give them a good cleaning and refreshment because my rusty tank has been letting sediment into the bowls (not to mention being run without an airfilter by the p/o has probably sucked something into one of the circuits.

Anyways, I bought rebuild kits, and they came with lots of fun looking things like springs, o-rings, float bowl gaskets, float valves, etc. Well, the only thing I could find in my KZ440 G1's CV carbs to change was the float bowl o-ring and the float valve. I have all these left over parts, and I don't know where they go!

Another thing, the guy at Sirius who sold me the kits sold me a kit for a KZ440 and one for a KZ750. He said they had all the same parts in them, and it looked like they did, but when I put it all back together and put the petcock to prime, it started pissing fuel out of the overflow tube from the carb I put the 750 kit parts in. I'm guessing since the only parts I used from the kits were the bowl o-rings and the float valves, the float valve was somehow different.

When I pull them apart again tomorrow, I'm going to reinstall my old float valve. I did put a makeshift airfilter and an inline fuel filter on it too BTW... If anyone can give me any insight as to where the extra parts from the kit (few small o-rings, a spring, a short threaded needle looking thing and some kind of thick metal disc) are supposed to be, that would be helpful. Thanks!

Post edited by: Alex_KZ1K, at: 2007/07/30 13:22

Hope this might help. Got it from www.kawasaki.com/DefaultFrame.aspx?strCo.../VICHOOSEVEHICLE.ASP

Hope this might help. Got it from www.kawasaki.com/DefaultFrame.aspx?strCo.../VICHOOSEVEHICLE.ASP

The KZ750 twin carbs are Mikuni and the KZ440 carbs are Keihin. I suspect that should tell you that they don't use the same kits. The 440 kit is made by K&L Supply. It contains the rubber oring bowl gasket, a float needle/seat assembly, an oring for the drain screw and a mixture screw "kit". The kit consists of a plug, a mixture screw (has pointy sharp end), a spring, a small metal washer and a very small oring. To swap mixture screws, you need to carefully drill the old plug using about a 1/8" drill bit and then use a nail or something small to work the plug out. It is glued in place. If you drill through the plug too deep, you will hit the old mixture screw so be careful. Anyway, with the plug out, unscrew the old mixture screw, pull out the spring, then pull out the old washer and oring. DO NOT leave those last two very small parts in the hole. To install the new mixture screw, turn the carbs on their side. Put the spring on the screw. Put the metal washer on the screw so it will fit under the spring and then put the oring on the screw. The washer is there to prevent the spring from ruining the oring. The carbs are on their side so all this junk doesn't fall off from gravity as you install. Put the screw with all the parts installed on the screw in the the hole and screw it till it is LIGHTLY (REPEAT) LIGHTLY seated. If you jam the pointy end of the screw in the hole, it WILL BREAK... they you will have to try and figure out how to get the tip out of the very small hole. Not fun... anyway, once lightly seated, back the screw out two turns... that would be turn the slot 360 degrees twice. Don't bother putting the cap back in place over the screw as it is only there to keep folks from doing what you just did.

Last note... the oring for the bowl won't stay in place unless you glue it. I use superglue.

Post edited by: wiredgeorge, at: 2007/07/28 09:45

Ok, well I got it all done. I got the carbs disassembled, fully cleaned with cleaner and compressed air and reassembled. It does run a bit better now, but it still takes a long time to warm up, and hisses and pops through the right pipe while on choke. I'm not really sure what to try next... :side:

If it makes any difference, I can't seem to set the idle either. I adjust it so it's between 1300-1500, then when I reach another light it's either too low and it stalls, or its revving at 2500 and I have to adjust it again.

Is there something else I need to adjust somewhere?

Sounds like an air leak. Check seal of carb holders. Make sure you installed the small crush washers on the sync port screws. Make sure you installed the pilot mixture screw orings in the manner I have already explained in a previous post. One of those things is your issue probably.

Thanks WG, I checked it out again more closely this time and it looks like I have some nice cracks in the tops of the carb boots, mostly on the RH one. That's first priority, I'm going to try some RTV as a test solution, then I will replace them. I don't remember removing any sync port screws, but the pilot screws I installed exactly in the manner you described, it worked like a charm. Thanks!

On most Kaws there is a vacuum port fitting that you slide a hose onto to sync. On your Keihins, there is a hole in the side of the carb with a brass screw. You unscrew this screw and use and adapter screwed into the hole and then put the carb sync tool hose on the adapter. The screws have some sort of crush type washer to ensure a good seal.

If I owned a bike with ANY sign of crack in a carb holder, I would NOT start the bike till I had replaced the carb holders... an air leak in the carb holder focuses cold air in ONE TIGHT SPOT on your piston crown and you will QUICKLY burn a hole in the piston. I know this from personal experience. Just buy new carb holders and hold off from doing any "experimenting". BTW: The carb holders on the bike where I holed the piston had been fixed with RTV... you don't fix those cracks... You might hide them, but air will get in. I also suspect that when carb holders crack, they are also stiff and don't seal well against the cylinder head.

wiredgeorge wrote:

On most Kaws there is a vacuum port fitting that you slide a hose onto to sync. On your Keihins, there is a hole in the side of the carb with a brass screw. You unscrew this screw and use and adapter screwed into the hole and then put the carb sync tool hose on the adapter. The screws have some sort of crush type washer to ensure a good seal.

Alex is right when he said he couldn't recall removing any brass screws. There are no screw-in vacuum plugs on his carbs.

Oh, and no plungers either.

Post edited by: ibsen22000, at: 2007/07/31 12:05

There are vacuum ports, one on each carb. One is capped, one drives the vacuum activated petcock valve. I'm going to try replacing that vacuum hose, it looks like it may be a little dry on the outside

Sorry, was thinking of another model. The pilot mixture screw info was correct... there is a small washer under the spring and then the oring. If the oring is damaged on not in place, the bike's idle will be erratic.