KZ 900 1976 choke starter plungers

My Bike has been at the workshop for weeks, the carbs constantly flooded with gasoline, plugs caked in black soot. The jets are original size, new seals - all good. The mechanic has been advised its the Choke Starter Plunger Assembly. I can't find this part anywhere, although I can find the Choke Plunger Seal which sits at the top of the assembly. Is there any chance its the seal and not the actual plunger? Any experience out there with this problem?

Many Thanks

Dave

Howdy. I'm not familiar with the KZ900, but the starter (choke) plungers have rubber pads on them that can get hard & not seal properly. My bike has VM24 carburetors. If the pads get hard, I plan on getting a leather punch or similar tool to cut new pads from viton or nitrile sheet rubber & probably glue them in place with Seal-All. or maybe Permatex liquid metal.

KZ900 starter plunger ---- 16016-017 --- 2nd pic shows the pad

Awesome mate, thanks. He pointed at those pads. Looking at lack of availability for the actual plunger, your solution looks like a strong possibility. I think I'll buy new Plunger Seals too as a belt and braces solution...

The pads aren't available as a separate part. I've never heard of anyone making them, but it seems like a simple solution that ought to work. Seal-All is supposed to be fuel proof, but I've never used it. I've had good luck with Permatex liquid metal which is some sort of epoxy that kinda feels like plastic when it dries. I used it to seal the fuel level switch on my 81 650. That was a couple of years ago, and it hasn't leaked since in spite of being in constant contact with gasoline.

Other rubber parts. There are also o-rings & rubber caps on the starter plungers. I think Z1Enterprises.com has them.

Theres a possibility its not these, but the mechanic seems to think so. The bike is guzzling fuel, despite the refurb the carbs did leak although I think not anymore. The plugs are completely sooted up after just a ride round the block.

I don't know if new pads or new starter plungers will solve your problem.

Aren't sooty plugs usually an ignition problem?

He's gone through the ignition, it seems that all is good there and functioning. When the carbs are replaced all seems well for a few minutes on the road then it all starts to run rough. He got to the fuel problem because the carbs were leaking and we were using literally litres of fuel on a short run. I might be wrong though, I'm open to all suggestions. I am in Spain, these bikes are rare here. I imagine unseen, though Mikuni's aren't so rare.

Is the battery good? fully charged & load tested? .... is the stock airbox installed?
Did he do a service fuel level check? ---- using a clear tube to see where the fuel level is. usually 3.0 mm below the bottom edge of the carburetor body.

Battery is brand new and stock airbox is installed. I'll check see if he did the fuel level check

Even with a new battery, you should charge it with a good smart charger & do a load test. Do that stuff & if it's fine, then move on to the next thing. I got stranded last August & thought it couldn't be the battery -- it was the battery. doh. I use a VC97 digital multimeter & a Ctek US 0.8 smart charger. IMHO a digital multimeter is better than an analog meter for checking the battery voltage.

Simple load test (engine off). charge the battery with a good motorcycle charger. It should be at least 12.6 VDC, but a good battery will be higher. Turn ON the ignition switch & headlight high beam (engine off). The voltage should drop to about 12.2 VDC. If it drops to around 11.85 VDC or a little less, the battery may need replacing. If it drops below 11 VDC, the battery is probably shot. These are the voltages I use. There may be a more accurate chart on the internet.

IMO, fuel overflow is likely not due to the choke plunger.

Usual "flooding" suspects would include:
Leaking float valve(s);
Float upside down, sticking, leaking or tab setting;
Fuel level (not physical measure of float height).

Would check for potential motor-destroying fuel-contaminated crankcase oil.

Good Fortune!

I'd email Mike at jetsRus.com and ask him if he has any.
Steve
jetsrus.com/#