Fuel/Air mixture problem

1980 kz440
I've been having trouble getting the right fuel mixture to my carbs. I just recently got the float levels correct (thanks bountyhunter) but the bike still doesn't want to get going above 4K RPMs. It also wants to stall when i come to a stop unless I give it a little throttle. I noticed in the left carb that it is missing the little plastic plug that covers the pilot jet. What is that for? Would that be causing me any problems? I have already made sure all of the passageways in the carbs are clear and checked the petcock to see if it works. It works great in prime. I'm not sure how to check if the vacuum is working. Any other suggestions??

Paging Dr. Wiredgeorge........

I'm not sure about that, Wiredgeorge is the resident carburetor expert.

Flip your petcock over to prime and take it for a short ride. If the problems go away you know your issue is caused by poor fuel delivery, easy 'nuff.

Thanks for the advice anarki650. That was actually my next plan of attack. I'm just hesitant to put the carbs back on the bike till I know what the plastic plugs are for. I don't want to have to pull them off again just to replace that. Anybody know?

Hi Mike,

Those plastic plugs are required by the Govnmn't because they've learned that if you can't see a problem it doesn't exist. Their reasoning is that if the owner doesn't know that the idle mixture can be adjusted, it won't be.

If one of your idle screw covers is missing it's no big deal.


"I have already made sure all of the passageways in the carbs are clear..."

If one of your carbs still has it's cover on the pilot screw, you haven't yet checked all the passages.

What do your spark plugs look like?

KZCSI

Lord! Free advice is worth every cent bwhahahaha BILL! The plugs over the pilot jets are to keep gas from entering the pilot jet well and FLOODING the pilot jet. Gas gets to the pilot jet via a cross passageway from the main jet well. The bike won't run right till a new plug is secured and installed. I know you can get them. Get the Kaw part number and call Z1Enterprises.com and order one.

Thanks so much for the info wiredgeorge. I figured it might have something to do with my problems.

The plug has an oring and is made of white plastic that turns reddish brown over time. I am not really sure if you could use a Suzuki style plug which is just a black rubber cork essentially. The main thing would be the installed height because there is a nub cast into the bowl that pushes down on the the plug to keep it in place. If the rubber plug was shorter, the nub wouldn't reach it and it would eventually leak gas without having a mechanical keeper method. Plugging the pilot well is a fairly common practice. You can see a cross passage but another easy way to tell if your carb has this feature is to remove the pilot and main jets and spray carb cleaner in the pilot air jet located on the venturi edge. If it needs a plug, gas will come out both the pilot and main jet wells.

Sorry Mike, You did say "pilot jet" didn't you.

Thanks for the correct info WG.

KZCSI