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Hey all I picked up this bike for a song and dance a couple months ago from another marine that was deploying and didn't want to deal with shipping it anymore. Anyway it's. 2012 with 3034 miles, and I am having a heck of a time with the idle. This is what I've done:

Cleaned the carb and all the Jets, slides, tubes, float, choke, diaphragm, and needle. About 4 times now

Adjusted the valves, then adjusted again.

Changed the carb gasket... Really don't trust o rings.

Sprayed wd40 around the boot to find an air leak.. nothing.

Honestly I'm out of ideas and was reffered here by the fine folk at Advrider. Couple members say you all know your ****. Hahaha
 

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Can you adjust the air fuel screw or is the plug still over it? There is something still blocking fuel in the pilot circuit. Did you pull out the pilot jet and clean it?
 

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First of all welcome to the group and if you are in the service thank you to you and your buddies! As for your problems with the idle have you looked at the other basics, air filter/box, fuel petcock and fuel filter, drained and added fresh gas, spark plug and wiring to name a few. There are other things like checking compression and looking into the cylinder for carbon build up. ....and if all of this checks out there are plenty of members here with a lot of experience with these bikes so sit tight as help is surely on the way!
 

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Does the idle surge up or down? How does it start, warm up and run? Any popping, backfiring, sucking air noises or anything else? Have you tried 3 or 4 ounces of Seafoam to help clean and unclog the carb? Was it riden daily or stored weeks or months at a time? The more we know, the better we can help.

O yeah, and Welcome to the forum!! :D
 
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Discussion Starter #6
Can you adjust the air fuel screw or is the plug still over it? There is something still blocking fuel in the pilot circuit. Did you pull out the pilot jet and clean it?
Pulled the little rubber cover and cleaned that out and the pilot jet is as clean as a whistle.


First of all welcome to the group and if you are in the service thank you to you and your buddies! As for your problems with the idle have you looked at the other basics, air filter/box, fuel petcock and fuel filter, drained and added fresh gas, spark plug and wiring to name a few. There are other things like checking compression and looking into the cylinder for carbon build up. ....and if all of this checks out there are plenty of members here with a lot of experience with these bikes so sit tight as help is surely on the way!
Pulled the fuel petcock, cleaned out the vents, piston looks cleanish with a flashlight and straw scraping. Compression hits at a constant 149psi across 2 testers in my garage. Checked the timing as well a few times. 9 years in the service so far, love it. New spark plug and air filter. It had his gas in it with stabil. I can do a fresh swap and try that.

I've worked on 2 strokes my whole life. This bike screams air leak but I'm coming up short on where it could be if it is one.

Thank you for all the warm welcomes!
 

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Discussion Starter #7
Does the idle surge up or down? How does it start, warm up and run? Any popping, backfiring, sucking air noises or anything else? Have you tried 3 or 4 ounces of Seafoam to help clean and unclog the carb? Was it riden daily or stored weeks or months at a time? The more we know, the better we can help.

O yeah, and Welcome to the forum!!
Idle continues to climb and climb, adjustments to the idle screw do nothing in terms of calming the beast. It does backfire through the carb a couple times when choked to first start, then after choke is off that goes away and it still climbs and climbs. I used carb cleaner and soaked for 3 days before using a small wire and air compressor to clean out the openings in the carb and jets...ect. it was ridden until it broke a valve guide. Bought a new head, piston, gaskets, and rebuilt the top end completely.
 

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Have you checked the valves to see if they are within spec? Did you adjust the mixture screw? They are lean from the factory and need to be lightly seated, then dialed out to 2 1/2 turns out or so to begin with...

The pilot jets are so hard to clean and sometimes its just worth it to throw in a new OEM one. If you go this route, throw in a new main jet too.
 
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Discussion Starter #9
Have you checked the valves to see if they are within spec? Did you adjust the mixture screw? They are lean from the factory and need to be lightly seated, then dialed out to 2 1/2 turns out or so to begin with...

The pilot jets are so hard to clean and sometimes its just worth it to throw in a new OEM one. If you go this route, throw in a new main jet too.
Triple checked both valves and adjusted to what the manual asks for. I'll start with 2 1/2 turns after kiddo time and dinner and report back. Thank you!
 

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Discussion Starter #12
1. Vacuum leaks: When you checked with WD40, did that can have a flammable propellant? Might want to recheck with unlit propane.

2. Vacuum operated slide: Does it fully close?

3. Coasting enrichener: Is it hanging up?

4. Does mixture screw have all parts present?

See photos in this thread: http://tw200forum.com/forum/technical-write-ups/881-tk-carb-photos-parts-identification.html

5. Throttle cable have proper slack? Does butterfly close?
Tried propane torch gas. No change

Vacuum slide tested with low air pressure blowing, works great

Not sure what the coasting enrichment is?

All parts there. I used that thread to rebuild actually

And yes, all parts.

Tried a carb off a locals bike. Same reaction. So now I'm back to square one lol
 

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Hey all I picked up this bike for a song and dance a couple months ago from another marine that was deploying and didn't want to deal with shipping it anymore. Anyway it's. 2012 with 3034 miles, and I am having a heck of a time with the idle. This is what I've done:

Cleaned the carb and all the Jets, slides, tubes, float, choke, diaphragm, and needle. About 4 times now

Adjusted the valves, then adjusted again.

Changed the carb gasket... Really don't trust o rings.

Sprayed wd40 around the boot to find an air leak.. nothing.

Honestly I'm out of ideas and was reffered here by the fine folk at Advrider. Couple members say you all know your ****. Hahaha
Have you tried adjusting the air pressure on the Power Band?
 

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Discussion Starter #16
Did you check your timing mark and adjust the cam chain tensioner?
Checked the timing mark and it aligns with the third to the right mark and the T mark on the cam gear.

Can you adust the automatic tensioners?


Have you tried adjusting the air pressure on the Power Band?
How do you do that? Thought only 2 strokes had a power band.
 

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Checked the timing mark and it aligns with the third to the right mark and the T mark on the cam gear.

Can you adust the automatic tensioners?
Mine is a 1993 so I'm not sure if it is the same. I unscrew the plastic cap then just make sure the tension rod position is 0-.5 mm or 0-.02 inches. Typically I just make it flush and then screw it in a tad.




How do you do that? Thought only 2 strokes had a power band.
It's a going joke. We soup up the TW with a power band. Do a search on it sometime, great comments.
 

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I have been watching this topic and I don't have any other good ideas. I really want to know what is going on.

My only guess is that the float level is too high and the excess gas is causing the over-reving. The increase in speed causes more gas to get sucked in and the engine runs even faster.

Or, the throttle cables are hooked up backwards leaving the butterfly open when it should be closed. You wouldn't do that, would you? I know I might.
 
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