Idling issue (79 kz400)

Loosened pilot screws to the point that they almost came out and still doing the rev thing.

Guess I need new pilot jets. Bummer.

Where is the best source for them? I have only found a couple on ebay.

treitz wrote:

Loosened pilot screws to the point that they almost came out and still doing the rev thing....

Could try tightening the pilot screws instead of loosening them, and see what happens.

If the carbs at hand are supposed to have o-rings on the pilot screws, would check for existence and condition of the o-rings.

Good Fortune!

treitz wrote:

...Guess I need new pilot jets....

Thinking pilot jets aren't causing the racing idle.

Would suspect air leaks in carb holders are the problem.

Attempting to "seal" old cracked worn out leaking carb holders is imo a losing proposition.

Gasoline proof sealants aren't heat proof.

Heat proof sealants aren't gasoline proof.

Permatex doesn't list a sealant that's purportedly both gasoline proof and heat proof.

Good Fortune!

Thanks for the input patton. I will check for leaked and o-rings and see what I find.

Patton wrote:

Permatex doesn't list a sealant that's purportedly both gasoline proof and heat proof.

Sorry bud, but the dirtbike guys and myself have been using this for years:



Gasoline/damaging fluids resistant, 350F continuos use.
Works for everything but the head gasket.

Patton is correct in suspecting not the pilot jet now, because if it were the mixture screw would have made enough difference. The only 2 other options are that you do not have sufficient seal to the head, or filters. System needs to be air tight from filter to exhaust (other than bowl vents) to work properly.

PS. The K&N filters flow ALOT more air than stock, dont be fooled!

Peace.

If not already done, might want to check other potential sources of air leaks, such as integrity and fitment of caps (plugs) on vacuum nipples, vacuum hose to petcock (assure it's uncracked) and that attachments at both ends are snug and secure, and that carbs are fitted fully into the holders and the clamps are secure.

Forgive if already mentioned, but could spray WD40 or carb or brake cleaner in carb holder areas, on vacuum nipple plugs, etc., while engine idles to see whether it's being ingested as evidenced by smoke from the exhaust or change in rpm.

Might get better coverage by spraying instead with propane gas (unlit --Duh :lol: ) which should also provide evidence of an air leak.

Sometimes a sticking throttle tube over right end of handlebar obstructs full closing, or perhaps gunge inside where the cable attaches.

Might disconnect throttle cables at the carb and operate the bell crank by hand to assure the carb return spring is strongly snapping the carb fully closed against the thumb screw stop, as it's supposed to.

Good Fortune!

I used a sealant very similar to that on my intake boots. I think it worked but will have to check again.

You say that stuff seals gas... So it would work as a float bowl gasket?

Where do u buy it an how much $ is it?

I'll check everything out again. I do not have the vacuum hose connected. I have it capped off at the carb and the tank.

TeK9iNe wrote:

Patton wrote:

Permatex doesn't list a sealant that's purportedly both gasoline proof and heat proof.

Sorry bud, but the dirtbike guys and myself have been using this for years:

Gasoline/damaging fluids resistant, 350F continuos use.
Works for everything but the head gasket....

That's pretty good stuff, and could work temporarily while being challenged with cylinder head heat and a gasoline environment. But wouldn't want to get very far out of town with it on a street bike.

Imo there's critical difference between "gasoline proof" and gasoline "resistant."
(Think water-proof vs. water-resistant.)

My understanding is that many have attempted over the years to rehabilitate leaking carb holders by using methods ranging from electrical tape wrapping to all sorts of sealant products, both Permatex and other brands.

While some have enjoyed rather short term success, reports of any long term success have eluded me.

Meanwhile, I concur with wiredgeorge's advice on the wgcarbs.com forum:
The old carb holders should be tossed. I do NOT use sealant. I use new carb holders. They might seem solid and OK to you but if they have been on the bike for a few years, they could use replaced.

Ya pays ya money and takes ya chances. :woohoo:

Good Fortune!

Also interesting ---

www.kzrider.com/archive/viewthread.php?tid=10207

Cool thanks.

#1 priority right now is replacing my leaky float bowl gasket. Having gas leaking while trying to trouble shoot engine is not working out well.

Damn float bowl gaskets are pricey though. Not to mention I JUST replaced them both but upon removal one stretched and got all jacked upon re-installation. Frustrating.

Once I get that fixed I can get back to adjusting the idle.

treitz wrote:

...#1 priority right now is replacing my leaky float bowl gasket...pricey....

kawasaki.com says part #16019-024 is "active," thus available at dealerships.

Before paying dealer price, would suggest first inquiring at Z1E.

Don't see a current ebay listing for the part number.
But would continue monitoring ebay.

Good Fortune!