choke plate

Does the choke plate always have a vacuum relief plate (the little spring operated door) in it? Two of mine carbs do and two of mine don't.

There seems to be only one part number for the choke plate. So, I'm assuming they always have the plate.
Do I really need new choke plates?

Both of my bikes are different.....with the same carbs :blink:. My '79 kz400's CV 34 carbs have the vacuum relief plates and my '82 kz750's CV 34 carbs don't. Not sure what works better since I haven't gotten the 750 running yet....but I'm close! :woohoo:

The TK-22 carbs (which are on the 550 A, among other bikes) should have the trap door on all choke slide-plates. They occasionally fall off. You have to inspect the pivot shaft on the slide-plate. They should be staked in, but come loose from vibration. Be extremely careful if you have to re-stake the shaft in place. The metal is very brittle. You may be better off trying some epoxy etc.

If the shaft is loose or out of position, the trap door does not shut 100% and this makes it need a lot of throttle to start. Some people had success making their own trap door replacements. Another thing you may want to experiment with sealing off the opening of the missing trap-doors. Someone tried experimenting with that and had some luck. You just have to be quick to open the choke while cranking. Then it will be very sensitive to choke action while warming up.

Also, you may want to take a look at this mod. It's for the same carbs you have:
www.geocities.com/loudgpz/GPZchokeScrewMod.html

There's always a set of carbs on ebay. You want carbs from 80-83 550A, 80-83 550C, or 81 550D (painted black with different main jets).
Here's a set from a real quick search.
buy it now $50 tk-22 carbs

These are over-priced for the condition. They should be about $20 in that condition. Absolutely ask for confirmation that all 4 chokes are complete with trap doors before buying. Often a few are missing.

Post edited by: loudhvx, at: 2007/11/29 18:07

Would it make sense for this to be an intentional modification?

The previous owner said he ran the bike with the choke closed. This would indicate the bike ran lean without the choke. He installed an inline fuel filter which may have cut the fuel supply slightly. I am guessing that running the bike with the choke closed evened out the air/fuel mix. So would it make sense to alter the carb this way, removing the doors so the bike ran smoother while the choke was closed?

I'm new to bikes so I am not sure if this makes sense.

The reason why I ask is that it seems strange to me that the door pins and springs are still looking great, but the doors themselves are missing.

Well, he may have removed two doors, but that means two cylinders were running super rich while the other two were running rich at wide open throttle. Either way, it would be a terrible mod to remove the doors.

When the carb is jetted right, the choke works pretty well in the stock form. The motor does take a while to come off choke on the TK-22's, but once you get the knack of how to control the choke lever, it's not bad.

Is the airbox on?
Is the exhaust stock?
If so, then the stock jetting should be right. If the carbs are thoroughly clean, any performance problems will probably be engine or ignition related.
Has there been a compression test?
Have the valve clearances been checked?
Has the ignition been verified to work correctly?

It looks like i should take a picture of the choke plates i filled with epoxy:)

With the carbs disassembled. I removed all the hardware and filled the opening with epoxy. Then i added another indent to the choke arm so i could put the choke lever at a position where the choke plates were slightly open. I have not had this bike on the road yet but the few times i have run the motor it seems to work!

If the plates come off they go thru the motor and can cause some damage. On my my bike it pinched the ring groove tight to the ring as it hammered on the top of the piston:woohoo:

Hope this helps

Yeah. The previous owner sold the bike to me because the last time he rode the bike it had developed a strange clicking, or "ting" noise.

So here's the order of events for the possible demise of this bike:
1. Bike develops a ting! He thinks its the clutch because it only happens when the bike is in motion.
2. Owner stops riding her because is concerned about his safety. It sits for a year before the owner finds time to work on it.
3. In an effort to restart her, Carb is cleaned by owner.
4. Bike will never restart for him again.

Hmmmm... must be rocket science. MAYBE IT HAS SOMETHING TO DO WITH THE MISSING CHOKE DOORS (I ask sarcastically)

Could choke doors actually end up in the engine without him noticing a problem at idle? I will bow my head and pray while I wait for any responses.

Sounds good Harm, I may try the seal off experiment some day. I definitely wish they had put more detents on the choke lever.

Fishybass, as far as the metal in the engine, can you peek into the cylinder through the spark plug hole and see if the piston has scratches on it? That might let you know if it's in there... or at least was in there. The bad news is that it really couldn't go anywhere else. The good news is that there is a small chance it made it through to the exhaust.

Post edited by: loudhvx, at: 2007/12/07 12:36

loudhvx wrote:

The TK-22 carbs (which are on the 550 A, among other bikes) should have the trap door on all choke slide-plates. They occasionally fall off.... You may be better off trying some epoxy etc...

Anyone use JB Weld/liquid metal in carb mods?
I have been pleased with my results using JB Weld in all mods/repairs so far. I have never used it in a fuel contact situation, but I think it is supposed to be chemically inert.

Thank you everyone who has helped me through my pains and sorrows in my first fix the bike excursion.

So, for those who are just tuning in... I've cleaned, and made minor repairs to my carbs. They are ready to be installed. Now what?

Can I just install them and start the bike up and go, or are there other things I should be planning on doing first?

This might just be the last post on this thread. Yippee!
The choke plates have been repaired. I was not going to spend outrageous money on new choke plates, and epoxy can be too brittle to stand up to any application involving the intake to my engine. So, with some patience, 26 gauge steel plate, and a good pair of snips I ripped out a good choke plate valves and used it to pattern three new valves.