I installed second set of bowl gaskets. Leaking!!!

jakedude wrote:

car5car wrote: I left petcock in "prime" position! My fault! Thanks for all responses!
After turning it to "on" leak stopped.
I still see wet bowl very close to gasket, but there is no dripping.
I checked petcock, it was working fine, so gas shouldn't flow in carbs.

In my opinion you are still not out of the woods. It should not drip even with the petcock in the prime position. If it does, your float needle is not stopping fuel from entering the float bowl.

Heed these words, I guarantee they are true. If the needles and seat faces are smooth and sealing well, and the fuel levels are adjusted correctly, you can leave the petcock ON or in PRIME or whatever without any flooding or rising. I do it all the time. I turn the petcock off only at night and leave it ON all day when I am using my bike. It NEVER floods until the needles get gunked up.

A vacuum petcock is actually compensating for faulty needles by cutting off the flow automatically. The needles shouldn't need that backup but it will keep the carbs from flooding out when the needles need work.

If your float and float needle are not stopping fuel when the petcock is in prime and the bike is not running. Then it is they are not stopping fuel when you are riding the bike.

True, but if the needles are only leaking slightly then when running, the engine may be draining the bowl fast enough you don't notice....... or you don't notice until it's idling and it starts to sputter because it's rising and flooding. Guess how I learned that......

bountyhunter wrote:

jakedude wrote:

car5car wrote: I left petcock in "prime" position! My fault! Thanks for all responses!
After turning it to "on" leak stopped.
I still see wet bowl very close to gasket, but there is no dripping.
I checked petcock, it was working fine, so gas shouldn't flow in carbs.

In my opinion you are still not out of the woods. It should not drip even with the petcock in the prime position. If it does, your float needle is not stopping fuel from entering the float bowl.

Heed these words, I guarantee they are true. If the needles and seat faces are smooth and sealing well, and the fuel levels are adjusted correctly, you can leave the petcock ON or in PRIME or whatever without any flooding or rising. I do it all the time. I turn the petcock off only at night and leave it ON all day when I am using my bike. It NEVER floods until the needles get gunked up.

A vacuum petcock is actually compensating for faulty needles by cutting off the flow automatically. The needles shouldn't need that backup but it will keep the carbs from flooding out when the needles need work.

If your float and float needle are not stopping fuel when the petcock is in prime and the bike is not running. Then it is they are not stopping fuel when you are riding the bike.

True, but if the needles are only leaking slightly then when running, the engine may be draining the bowl fast enough you don't notice....... or you don't notice until it's idling and it starts to sputter because it's rising and flooding. Guess how I learned that......

First, sorry about my poor writing. I should have written "If your float and float needle are not stopping fuel when the petcock is in prime and the bike is not running, then they are not stopping fuel when you are riding the bike." Bountyhunter thankfully caught my meaning.

In addition, again check your oil. You have likely been getting fuel in your oil if it has been flooding. When flooding, fuel drains from your carburetors into your cylinders and then into your crankcase.

Bountyhunter also said.

bountyhunter wrote: Guess how I learned that......

He learned that the same way I did.

And the same way I did.

Some carbs have an overflow circuit.

Some carbs such as Mikuni smoothbores and some stock carbs don't have an overflow circuit.

Where an overflow circuit is functional (not clogged), fuel that rises too high inside the float bowl due to a leaking float valve (or for whatever reason) is usually expelled before reaching the carb bore.

Where there's no overflow circuit or a clogged non-functioning overflow circuit, fuel that rises too high inside the float bowl due to a leaking float valve (or for whatever reason) can reach the carb bore, and then flow both ways -- toward the back (air intake side) and/or toward the front (engine side).

With an airbox, some models such as Z1 allow fuel from the carb bore to drain via the stock crankcase breather hose directly into the crankcase. [With thanks again to Jeff Saunders of Z1 Enterprises for his kindness years ago in taking the time to personally explain this to me.]

The following image is for illustration only, and is not to scale:


With carbs having no overflow circuits, it's especially important to assure properly functioning float valves.

For example, if while riding, fuel rises in one carb due to a non-functional float valve, and reaches the carb bore, which floods a cylinder so that the cylinder no longer combusts and allows some incoming raw fuel to drain into the crankcase, continuing to ride keeps allowing more fuel entry into the crankcase.

Fitment of a good aftermarket in-line fuel filter should help keep the float valves in good clean serviceable condition.

Good Fortune!

The Z1 air box has a drain that is lower than the breather tube. The KZ 900 air box gas two like mine. They're more for water than anything else. It is possible gas can get into the engine if the leak is really bad through the intakes. I had a needle and seat that wouldn't seal. I put the needle in a piece of tubing, spun it with a drill on a flat stick with #600 paper until the grove was gone. I had to whittle a # 2 pencil so it would fit inside the seat, used fine grinding compound to refinish it. The pic shows a VM 28 seat and you can see the line it made on the pencil. The 33's are much larger. You an barely see where it sat. It's been working for a year now.
Steve

No eBay APP ID and/or Cert ID defined in Kunena configurationThanks for all responses, I bought used 4 valves from ebay. Hopefully they are better than mine.

The pictures show the wear rings where the needles ride the seats. That's what you need to smooth out to get the perfect taper again to get a good seal. Put the needles in a hand drill and use some 400/600 paper on a popsicle stick to polish the taper until it's good again. You can also spin the brass seats and use a Q tip to polish the insides with a bit of chrome polish. make sure the seats are dead smooth and free of any burrs or rough spots. Put a bit of masking tape on the threaded portion to protect the threads.

swest wrote: I had to whittle a # 2 pencil so it would fit inside the seat, used fine grinding compound to refinish it.

On mine I had a popsicle stick tool I made by narrowing it until it just fit in the seat and then snipping the end to match the taper of the needle's head. I would spin the brass seat and push the stick in after I dipped the end in polish.

Thanks! I'll try. I don't understand how to center square valve needle in drill chuck.

A piece of tubing.
Steve

car5car wrote: Thanks! I'll try. I don't understand how to center square valve needle in drill chuck.

You can wrap it in tape or put it in a piece of rubber hose.