Leaking fuel out overflow when park - 1980 KZ440

That makes sense that they wouldn't have a vacuum petcock with an off position. I'll rebuild the stock and keep a plug with me just in case for emergencies.

As far as rebuilding the carbs, it was recommended I keep all parts as long as they are in good shape, but if I want to take the carbs apart and clean them I'll need to replace any gaskets. Is there a recommended kit for just the gaskets or should I leave the carbs alone?

jlouis wrote: ............... should I leave the carbs alone?

The carbs have a problem or they would not leak fuel regardless of any petcock problem. I would highly recommend diagnosing and correcting the carb problem. It may not require "rebuilding" the carbs. If you take look at my earlier posting at www.kzrider.com/forum/3-carburetor/60585...rk-1980-kz440#761083 you will see there are three likely problems that would cause the carbs to overflow. Correcting any of those three problems is pretty straight forward and does not require the carbs to be rebuilt. Ed

Call it what you will but with 37 year old carbs I strongly advocate a full teardown, clean out, and replacement of all O-rings, and any gaskets that are hard and brittle. Do this and the carbs will be ready for 37 more years.

A lot of guys are needlessly afraid of unganging the carbs for some reason, but unganging them is the only way to replace the interconnect O-rings. Just get on with it and do the job right the first time. It will save time in the end.

As for leaking float needles are concern, it's critical to make sure all the varnish is removed from the carbs and that there is no rust in the tank. Both of those things are sure to lead to fouling the float needles.

Nessism wrote: Call it what you will but with 37 year old carbs I strongly advocate a full teardown, clean out, and replacement of all O-rings, and any gaskets that are hard and brittle. Do this and the carbs will be ready for 37 more years.

A lot of guys are needlessly afraid of unganging the carbs for some reason, but unganging them is the only way to replace the interconnect O-rings. Just get on with it and do the job right the first time. It will save time in the end.

As for leaking float needles are concern, it's critical to make sure all the varnish is removed from the carbs and that there is no rust in the tank. Both of those things are sure to lead to fouling the float needles.

This is my mentality as well. Is there a site or kit with OEM O-rings and gaskets?

Nessism wrote: Call it what you will but with 37 year old carbs I strongly advocate a full teardown, clean out, and replacement of all O-rings, and any gaskets that are hard and brittle. Do this and the carbs will be ready for 37 more years. ....

I tend to agree with this but with a word(s) of caution. Some folks use the term "rebuild" with the thought that it requires replacing not only the rubber bits and gaskets but also the metal parts such as jets, jet needles, etc. Unfortunately, this belief often leads them into buying aftermarket metal parts which are not as precise as the original Mikuni parts, so there's a fair chance that when they are finished "rebuilding" their carbs they have replaced good metal parts with poor metal parts and caused more harm than good. I wouldn't advocate replacing any of the metal parts unless there is damage.

One other word of advice it to not mix parts between carbs. Some folks have done this only to discover that because parts have somewhat worn together mixing them around causes problems. I suggest using 4 plastic containers and keeping each carb's parts together in a separate container. Not hard to do and it may prevent problems. Ed

650ed wrote:

Nessism wrote: Call it what you will but with 37 year old carbs I strongly advocate a full teardown, clean out, and replacement of all O-rings, and any gaskets that are hard and brittle. Do this and the carbs will be ready for 37 more years. ....

I tend to agree with this but with a word(s) of caution. Some folks use the term "rebuild" with the thought that it requires replacing not only the rubber bits and gaskets but also the metal parts such as jets, jet needles, etc. Unfortunately, this belief often leads them into buying aftermarket metal parts which are not as precise as the original Mikuni parts, so there's a fair chance that when they are finished "rebuilding" their carbs they have replaced good metal parts with poor metal parts and caused more harm than good. I wouldn't advocate replacing any of the metal parts unless there is damage.

One other word of advice it to not mix parts between carbs. Some folks have done this only to discover that because parts have somewhat worn together mixing them around causes problems. I suggest using 4 plastic containers and keeping each carb's parts together in a separate container. Not hard to do and it may prevent problems. Ed

Thank you for the reminder Ed, this is my strategy as well. I am very meticulous and slow moving when it comes to my rebuilds.
Be one with the motorcycle...

Will the o-rings and gaskets be reusable? Where can I source new ones?

cycleorings.com sells a VM carb kit that should have most of the O-rings needed. You can get OEM parts from Partzilla.com

And there is always places like Z1 Enterprises

So i bought a petcock rebuild kit and it is still leaking fuel. Less fuel than before, but still leaking. Any suggestions?

I disconnected the fuel line and the vacuum line - so it is just the petcock on the tank and fuel is still dripping out the fuel outlet.

When you rebuilt the petcock, did you carefully clean and polish the seat for the oring and the face of the lever that presses against the large smily face rubber gasket? If not, surface corrosion and imperfections may prevent sealing. Did you use oem parts?

I took the face back apart, cleaned and tightened it well and it definitely helped. Still a very small drip this morning, thought I had it last night.
The parts are not OEM. I am going to order an OEM gasket for the lever, I think the supplied one is too small.

Petcocks can be troublesome. It's easy to just replace a few rubber parts and expect it to work like new. Sometimes it takes a little more.
This is the best petcock rebuild tutorial I have come across Yamaha petcock rebuild Yamaha petcocks are notoriously tough to stop leaking in my experience plus, there are two of them.