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When disassembling the carburetor, the small, short, aluminum nozzle above the main jet fell out. And I don’t know which direction it should be put back in. (When assembled, the carb/throttle needle is positioned vertically within this nozzle.)

The top and bottom of the nozzle are not symmetrical. One end’s opening is tapered or beveled; the other end’s opening is flat. And the end segments are of different lengths as they are separated by raised built-in bushing that is positioned off-center.

Please advise on how to reinstall.
 

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Same thing happened to me. I think it will only fit back in one way where the nozzle can screw all the way back in. Maybe the picture will help. Click on picture to enlarge.

Brass thing.jpg
 

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Bevelled end goes in first during re-assembly.
This a fairly small part that is easy to accidentally omit or mis-install during carb maintenance.
I lost track of one once somewhere in the ultrasonic cleaning process and ordered another only to later find the original hiding under a work table.
 
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Discussion Starter #4
Same thing happened to me. I think it will only fit back in one way where the nozzle can screw all the way back in. Maybe the picture will help. Click on picture to enlarge.

View attachment 207174
Same thing happened to me. I think it will only fit back in one way where the nozzle can screw all the way back in. Maybe the picture will help. Click on picture to enlarge.

View attachment 207174
Thanks elime. My bike is 2015; carb looks different from your pic, but seeing how your nozzle is seated helps.
 

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That part is called the needle jet. The needle moves up and down inside it. The main jet feeds it.
 

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Discussion Starter #6
Bevelled end goes in first during re-assembly.
This a fairly small part that is easy to accidentally omit or mis-install during carb maintenance.
I lost track of one once somewhere in the ultrasonic cleaning process and ordered another only to later find the original hiding under a work table.
Fred — it occurred to me that I’m not even positive which way it goes in —that is, from the top (carb throat side) or the bottom (float bowl side). I assuming it goes in from the bottom.

So to confirm — I should insert the aluminum nozzle, with its beveled end first, from the bottom or float bowl side and into the jet tube; then, insert/tighten brass “bleed needle” (8 mm); and, lastly insert/tighten brass main jet (7 mm) — is this correct?
 

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Discussion Starter #8
“A picture is worth a thousand words...”
___
No wonder, even after a diligent cleaning, that I can’t keep it running in any choke, idle, or throttle setting— I have the nozzle turned upside down.

The convex mating with the concave makes good sense.

Thanks jb
 

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Discussion Starter #9
When disassembling the carburetor, the small, short, aluminum nozzle above the main jet fell out. And I don’t know which direction it should be put back in. (When assembled, the carb/throttle needle is positioned vertically within this nozzle.)

The top and bottom of the nozzle are not symmetrical. One end’s opening is tapered or beveled; the other end’s opening is flat. And the end segments are of different lengths as they are separated by raised built-in bushing that is positioned off-center.

Please advise on how to reinstall.
PROBLEM SOLVED:

My thanks to jbfla, Fred, elime, and SkiPro3.

I had installed the nozzle incorrectly on Saturday —couldn’t keep bike running and wouldn’t idle.

Took carb off Monday (today). Removed float bowl, main jet, holder; and removed the diaphragm and main jet needle.

Nozzle was jammed because it was upside down. Had to tap it from the top to release it. Used a slim round, flat-faced punch that fit just right over the nozzle and within the orifice. It loosened and dropped out after two or three light taps from above.

Reassembled the top parts (diaphragm and needle, etc). Then installed nozzle correctly. This also allowed the main jet and its holder to seat correctly.

Bike now starts, runs, purrs, and giddy-ups on command.
 

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What jbfla's photo shows marked as 'main jet holder' I've always referred to as the needle jet. Notice it has holes in it just as the pilot jet. The needle goes up and down inside this jet and allows fuel to flow through those holes. There should be a number stamped on it as well and other size needle jets can be substituted. I don't have any further info about the TW200 needle jet, but I sure have a lot of experience with several other off road bikes and needle jets as well as needles.
Needles have a 'profile' to them; taper and length. The taper is very critical to getting the maximum performance out of the motorcycle's mid band throttle range. Some folks associate this with rpm, but it's more to do with throttle position. Pilot is no throttle, needle jet and needle are mid throttle and main is full throttle. (They all over lap and are cumulative, meaning the pilot circuit is active throughout the throttle range, and so on)

I mention all this because I wanted to clarify my previous reply earlier.
 

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Nozzle was jammed because it was upside down. Had to tap it from the top to release it. Used a slim round, flat-faced punch that fit just right over the nozzle and within the orifice. It loosened and dropped out after two or three light taps from above.
I've used a golf ball Tee to tap that nozzle out. I recommend if it takes more than a few taps with a metal punch, use a wood punch so nothing gets damaged in the process. Glad you got yours out safe and sound!
 

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What jbfla's photo shows marked as 'main jet holder' I've always referred to as the needle jet. Notice it has holes in it just as the pilot jet. The needle goes up and down inside this jet and allows fuel to flow through those holes.....
If you want to get technical, the main jet holder is actually an emulsion tube, where the process of mixing air and fuel begins.

The small holes in the side (which can easily become clogged) allow air, not fuel into the tube to begin mixing air and fuel.

jb
 

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Discussion Starter #13
I've used a golf ball Tee to tap that nozzle out. I recommend if it takes more than a few taps with a metal punch, use a wood punch so nothing gets damaged in the process. Glad you got yours out safe and sound!
Good tip. I was concerned about damaging it, so I tapped it cautiously.

This was the first time cleaning this carb. I learned a lot and benefited from doing it.

For instance, I also removed the plug from the air/fuel mix screw and backed it out another turn or so. Bike starts so easy now without the choke.

My TW is a 2015 —with only 1500+ miles. I use non-ethanol gas, but apparently it sits in garage too long between riding. I’m thinking I should drain or run the gas out of float bowl if I’m not riding regularly.

And, hey, if I use a golfball tee on it in the future— I’ll try not to hook or slice!!!
 

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Discussion Starter #14
If you want to get technical, the main jet holder is actually an emulsion tube, where the process of mixing air and fuel begins.

The small holes in the side (which can easily become clogged) allow air, not fuel into the tube to begin mixing air and fuel.

jb
If you want to get technical, the main jet holder is actually an emulsion tube, where the process of mixing air and fuel begins.

The small holes in the side (which can easily become clogged) allow air, not fuel into the tube to begin mixing air and fuel.

jb
This was first time cleaning the carb. Before I tackled it I found your post from 2010
If you want to get technical, the main jet holder is actually an emulsion tube, where the process of mixing air and fuel begins.

The small holes in the side (which can easily become clogged) allow air, not fuel into the tube to begin mixing air and fuel.

jb
This was first time cleaning the carb. Before I tackled it, I found your post from 2010 on cleaning TK carbs. It helped me greatly. That discussion was closed to new posts and perhaps that why the photos were no longer visible. Your sending the captioned photo on my post made it clear on how the nozzle should be positioned.

After disassembling and reassembling and cleaning, I have a lot more confidence in dealing with carb issues. I did find the part names and terminology a bit confusing at first, but I’ve got it down pretty well now. Thanks jb.

Mike
 

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What jbfla's photo shows marked as 'main jet holder' I've always referred to as the needle jet. ......
Needle jet = nozzle

jb
 
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