79 kz400 float needle seat question please help me

So I have what appears to be a poorly seating float needle. I have replaced the needle, polished the seat, inline filter, but still leaks occasionally. When I pop of the float bowl and give it a cleaning it works good again for awhile. I ordered a rebuild kit but it doesn't have the valve seat.

I cannot seem to find anywhere that sells the float needle valve SEAT and have no idea how to remove the existing one. Please God someone help me out here, is this seat part of the carb body itself ??

Thanks in advance to all and have an awesome 4th people !!!!!!!!!

Firsttimer1014 wrote: . . . appears to be a poorly seating float needle. . . polished the seat, inline filter, but still leaks occasionally. When I pop of the float bowl and give it a cleaning it works good again for awhile. I ordered a rebuild kit but it doesn't have the valve seat. . . cannot seem to find anywhere that sells the float needle valve SEAT and have no idea how to remove the existing one. . . is this seat part of the carb body itself ?? . . . .

My understanding is that the seats aren't removable and aren't replaceable.

Intermittent leakage -- but not persistent full time leakage -- from where the pointed tip of the float needle fits into the seat orifice indicates that the float valve is capable of functioning properly. When float valve leakage occurs, it's often due to being imperfectly clean where the pointed tip of the float needle fits into the seat orifice.

Other reasons why the float valve may leak could include a "sticking" or "hanging" float, whereby the float isn't able to perfectly function within the capability of its buoyancy, and is thereby unable to sufficiently hold with enough pressure the pointed tip of the float needle into the seat orifice. Imperfect cleanliness of the float assembly or damage to the float assembly or misalignment of the float assembly (such as a bent float arm) can result in a "sticking" or "hanging" float.

polished the seat -- What method is being used to polish the seat? A common method is with a q-tip chucked in a variable speed drill and using carb cleaner or perhaps a product such as "Brasso" to spin the q-tip inside the seat.

inline filter -- If it isn't a fresh filter of the following style, would consider replacing it.




It may also be time to disassemble and clean the petcock, and to flush/rinse the fuel tank. (And perhaps more aggressive cleaning of the interior of the fuel tank).

And assure that the fuel line(s) are in good condition.

Good Fortune!

Does your bike have Keihin carbs with the rubber tipped float needles? If so, they are persnickety and love to overflow. For one thing there can not be any debris entering the carbs as mentioned by Patton. I'm not sold on those gold-stone filters though since they are not the greatest quality and the stone is more a strainer then a filter. Better than nothing though. You really need to spend the time and do the clear tube test to be sure your float heights are all properly set. On most of the Keihin's I've rebuilt the fuel level was set too high and I had to bend the float tang a fair bit before the carbs would seal reliability. To measure is to know.

Nessism wrote: . . . do the clear tube test to be sure your float heights are all properly set. . . .

+1

Here's a link to download some info from www.kz400.com about the seat being not replaceable (see toward bottom of page 157).

After clicking the link, I use Adobe Acrobat to download the pages.

Click here > www.kz400.com/Workshop%20manual%20bilder...0man.%20p156-170.pdf





Good Fortune!

Clear tube test as already noted would be a great idea. I used an old clear fuel filter and cut the housing open and removed the filter, used ot as my "clear tube".



Also check to see how much wear is on the float tang where the spring loaded needle tip sits, I had an intermittent leak that could be stopped by tapping the gloat bowl with a screwdriver handle.
The float tang had a pretty defined dent in it where the needle rode, it was cocking the needle sideways in the seat.
I polished out the tang and no more leak.

Make sure the tang is not on too much of an angle. That will make the needle cock sideways and cause it to leak.
Steve