KZ550 pod filter question?

Anyone running pods on an 81 KZ550 with TK carbs? Running lean on 32 pilots 110 mains needles all the way up air screws 2.5 turns out. Just looking for what I need to do first.

Thanks!

The air screws being that far out make it leaner. With air screws, turning in makes them richer.

Your main jet is very rich. This is probably the result of compensating for mid throttle leanness. I suggest using the third groove from the top on the needle.

With pods, you will probably want 34 pilots.

Your major focus will be the needle position.

Check out the TK22 carb link for details on how to properly shim the needle and other tips. There a bunch of links at the bottom of the main TK22 page.
Check your fuel levels and rule out vacuum leaks or you are wasting time trying to rejet.

Also, before doing any motor work, read the valve train warning.

Thanks! I had these carbs tuned and running great on a different engine. It was worn an a little down on compression in a couple of cylinders so I made an engine change to a better one. Now I can';t get it to run. I was under the impression that that the air screws in leaned the motor by shutting off the air supply through that circuit in the carb. So I have it backwards?

lhemrick wrote: Thanks! I had these carbs tuned and running great on a different engine. It was worn an a little down on compression in a couple of cylinders so I made an engine change to a better one. Now I can';t get it to run. I was under the impression that that the air screws in leaned the motor by shutting off the air supply through that circuit in the carb. So I have it backwards?

Reducing air in the circuit increases fuel. So turning the air screw in makes it richer, Turning out makes it leaner. But mostly only affects idle. It may contribute a tiny bit just barely off idle, but not by much.

loudhvx wrote:

lhemrick wrote: Thanks! I had these carbs tuned and running great on a different engine. It was worn an a little down on compression in a couple of cylinders so I made an engine change to a better one. Now I can';t get it to run. I was under the impression that that the air screws in leaned the motor by shutting off the air supply through that circuit in the carb. So I have it backwards?

Reducing air in the circuit increases fuel. So turning the air screw in makes it richer, Turning out makes it leaner. But mostly only affects idle. It may contribute a tiny bit just barely off idle, but not by much.

Hmmm... not sure if that is right or not.
I was under the impression that with the modern EPA rules, those air screws are designed so that it can only make the idle circuit leaner, never richer.
In other words, turning the screw in tight to block all bleed air, doesn't increase any more actual fuel flow then it would/could no matter where the screw is, as the fuel part in the mix is limited by the construction of the carb and idle circuit.
In that type of carburetor, I've always assumed all you can ever do with screw position is make it leaner...is that incorrect?

missionkz wrote:

loudhvx wrote:

lhemrick wrote: Thanks! I had these carbs tuned and running great on a different engine. It was worn an a little down on compression in a couple of cylinders so I made an engine change to a better one. Now I can';t get it to run. I was under the impression that that the air screws in leaned the motor by shutting off the air supply through that circuit in the carb. So I have it backwards?

Reducing air in the circuit increases fuel. So turning the air screw in makes it richer, Turning out makes it leaner. But mostly only affects idle. It may contribute a tiny bit just barely off idle, but not by much.

Hmmm... not sure if that is right or not.
I was under the impression that with the modern EPA rules, those air screws are designed so that it can only make the idle circuit leaner, never richer.
In other words, turning the screw in tight to block all bleed air, doesn't increase any more actual fuel flow then it would/could no matter where the screw is, as the fuel part in the mix is limited by the construction of the carb and idle circuit.
In that type of carburetor, I've always assumed all you can ever do with screw position is make it leaner...is that incorrect?

There is nothing special about the factory setting of 1-1/4 open. The vacuum in the pilot passage sucks air and fuel. The screw controls air only. The air:fuel ratio is what we are talking about. Less air = richer. You can actually shut the air off entirely in the pilot passage. Then it is all fuel, but don't forget, there is air coming past the main slide too, so you don't cutoff all air to the engine.

If you increase the air, the amount of vacuum available to pull up fuel is reduced. You can open the screw so far that no fuel comes into the pilot passage. Normally the bike will not idle that way since the main slide is not usually letting in fuel at idle.

The port routing is described in detail on the TK22 site if you are curious.

Perhaps the idea of not being able to make it richer came from the fact that you are not directly metering the fuel, so it seems "set". So even though an air&fuel mixture screw lets you directly control the fuel metering, But in fact, by controlling air, you do also control fuel.

I believe the real reason, or best benefit, of using air screws is that there is no gummed up fuel in the screw metering passage... very nice. I've never had to replace or even clean the metering screws, really, unless a set of carbs was left outside in the rain or something.

That depends on the type of TK or other carbs. CV TK's like on the 550 have the screw in front of the slide. It meters fuel. The VM's have it behind the slides and it meters air.
Steve

swest wrote: That depends on the type of TK or other carbs. CV TK's like on the 550 have the screw in front of the slide. It meters fuel. The VM's have it behind the slides and it meters air.
Steve

He has TK22's.