Choke assembly leaking air

hey guys "1977 Kaw KZ750B Twin"i finaly found my air leak causing the bike to idle high after about 10 or so min of riding. It is the plunger to the choke assembly on the right side carb. Its seating corectly but the little rubber/grooved o-ring that covers up the base of the acual plunger rod, right where it exists the choke assembly is leaking air. Its not very tight at all. Without out replaceing the whole plunger and rubber o-ring type thing,im at a loss of what to use to seal it off.I dont want any RTV sealant to slide down the rod and get into the choke assembly so i need something else to use teflon tape maybe? Of course the main solution would be to buy the whole assembly new but that takes awhile to order ect. Any help would be great

del

You know that is a great idea, i muight have to try that, but actually it is number #22 the little rubber piece that is like a fat rubber o ring with a groove cut aroiund the whole rubber job to go over the metal piece #23 and the plunger rod #25 goes through the rubber o ring.Its kinda shaped and cut like a tire that hasnt been put on the rim yet. i guess ill just have to order the rubber job and a whole new plunger from bike bandit, only place i can find them "hope they got them in stock" But your idea is a very god one at that. Thank you very much ect.

del

The rubber pad on the plunger is what is leaking not the Starter Plunger Cap. The choke plunger itself is not the same as the VM series carburetors and I don't think it is the same as other BS series but I could be wrong about that... never thought to hold them side to side. If the choke plungers are removed, it would be a great idea to get the gasket(s) that sit under the choke plunger holder body(s).

hmmm very interesting wired george. That makes sense though that the acual rubber o-ring type gasket on the bottom of the brass plunger is leaking instead of the rubber plunger bumber gasket that is outside of the choke assembly. I did replace the actual gaskets that came with the carb repair gets for the choke body, unfortunately carb kits never seem to come with the choke plunger even though they give u a gasket lol. Ill have to order the brass choke plunger its self because it seems impossible to try to jerry rig a rubber type gasket in place of it. Thanks for the help guys.

one more thing after it warms up for about 10 min it starts to idle high of course because of the plunger leak.But i can ever so slightly raise the choke just a bit and it idles prett good and the idle goes down good after a rev. Is this a good idea to do this for the time being intill new plunger gets here? Or will this hurt or affect engine anyway for the short term or long term?? Thanks agian srry for long post

P.s. the only prob with getting a new brass choke plunger is that i cant seem to find them anywhere except for Bikebandit and it does not say that any parts are in stock or not just a price for them. Dont know who reliable they are and how quickly they could get to me nevver used them always Z1 or CrC2online. Any suggetions?

del

Thats what i figured Bikebandit couldnt tell me if they had anyparts in stock intill i place the order lol, never heard of that before,but they say they get the parts straight from the manufactor. So if its listed as cancelled on Kaws site then maybe bike bandit dosent have it either. This really sucks i finnally get my bike running great except for this liittle butt plunger deal lol thanks JMK

If any body knows of a source for nitrile rubber in small quantities, a square foot or so. I'd be interested.

Thanks
KZCSI

actually i found a roll of cork gasket and nitrile rubber sheets at Farm and Fleet, I might try that and see what i can do with that darn plunger. They were pretty cheap around 10 bucks or so for a pretty good size roll

Whheezzzz wrote:

...1977 Kaw KZ750B...found my air leak causing the bike to idle high after about 10 or so min of riding. It is the plunger to the choke assembly on the right side carb. Its seating corectly but the little rubber/grooved o-ring that covers up the base of the acual plunger rod, right where it exists the choke assembly is leaking air. Its not very tight at all...

If interpreting this thread correctly, the original source of air leak was incorrectly diagnosed, and now believed to result from a worn, torn or otherwise defective seal located in the plunger base around the tip of the plunger.

Replacing the entire plunger is now under consideration because the seal is not separately available and a new plunger comes with the seal already built into its base around the tip. As known, the metal tip and surrounding close the enrichener fuel passage, and the plunger also closes the enrichener air passage when in the down position.

Would it be feasible to remove the seal and flip it over to thereby gain a better surface for sealing?

It escapes me why a fresh seal could not be readily fabricated and fitted around the metal plunger tip (as suggested in earlier posts). Whether it be from nitrile rubber, or an inner tube, or some other soft rubbery fuel resistant material. When closed, am guessing it isn't constantly exposed to fuel because the fuel opening is closed by the metal tip (but may be wrong about limited exposure of the pad to fuel).

Am wondering if the air leak might actually be from some other source unrelated to the enrichener plunger seal. What is actual basis of the diagnosis now blaming the air leak on a faulty plunger seal? Was any test performed to substantuate this particular diagnosis?

Am thinking of the several other more common air leak sources, such as pin hole or tear in throttle slide diaphram, leaking vacuum nipple cap (or balancer tube), carb holder, etc. If not already done, would investigate these other possible air leak sources.

It would be disappointing to replace the entire plunger without resolving the problem.

Good Luck!