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  1. #1
    Junior Member DBuck42's Avatar
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    I just purchased a 2003 TW200RC with 700 miles that has been sitting for 5 year in a garage. I did all the fluid changes, flushed the gas tank and cleaned the air filter. Used Gum Cutter 2+2 and completely cleaned the carb. First carb. clean was the quick one, only main and pilot jet. It would not start. Then found the float value stuck, so cleaned the value and adjusted the float height and also cleaned the top of the main needle. It started with full choke, but any throttle and it would die. Then took the carb, completely apart and used the Gum Cutter to blowout all the passageways. Will the carb run lean like this if the air inlets for the pilot and main are clogged? I broke the 126 main jet so I can not try it again. I ordered a 128 main jet and added a very thin shim to the needle. Will this help richen the mixture? Will it allow the motor to run when the throttle is turned? I am a noobie at this. What should I inspect to look for any vaccum/air leaks? I am not sure how to determine if and where there may be a leak. Any help you can give me would be greatly appreciated. Thanks!



    Dennis

  2. #2
    Senior Member pgilles's Avatar
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    This sticky is for the carb you have: https://tw200forum.com/index.php?/top...dentification/



    First off, no bike came from Yamaha that didn't idle or would die when giving it throttle. Which means you have more going on in the carb than just needing more fuel from a larger jet and needle shim. Not trying to sound mean, just putting that out there



    Make sure the tiny o-ring that sits under the cover on the top of the carb is correctly seated. If you pulled the slide out of the carb then this could have lost its location.



    Back to the sticky, the fifth picture down shows a "pilot screw plug". Remove that plug (6th picture shows one of many ways to remove it), remove the pilot screw and clean it, as well as it's passageway. That circuit is what allows the bike to idle, when clogged it won't flow fuel and the usual indicator of this is having to use choke to keep it idling. This, of course, is provided you clean the pilot jet well...it's a tiny orifice so it doesn't take much to gunk it up.



    You cleaned the main jet and the needle, but sounds like you missed the emulsion tube/"main jet holder" as seen in the sticky's 2nd post, 4th picture. You can see it's just threaded in. Make sure that's cleaned up too.



    Make sure throttle cables are installed and adjusted correctly.



    Make sure the air cleaner is clean and there isn't a mouse nest in the intake.



    Last note, with the bike sitting for 5 years the carb needs a THOROUGH cleaning. Spraying carb cleaner on everything then some compressed air won't suffice. Chances are everything is CRUSTY with old gas residue. That needs a long soaking and/or abrasive action (sometimes I cut a piece of wire off my wire brush and use that for running through the jets). If you have an ultrasonic cleaner or have access to one, that'd be the cat's meow. Only have heard great reviews.
    Sold bike.



    Youtube vids of old TW's acceleration:

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  3. #3
    Banned qwerty's Avatar
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    Complete rebuild. I hope you've the time to do it right the third time.



    Fetch yourself a big cake pan and line the bottom with several layers of paper towels. Work over the cake pan. When you drop the odd small part it won't be as likely to bounce off into a black hole. Fetch yourself a couple muffin tins to organize the parts. Little slips of paper identify the parts. Fetch yourself a main jet and a little washer to fit over the needle. Print off the carb overhaul instructions from the free online maintenance manual and the parts blow-up from the parts manual. Study both well before attacking the carb. That way you'll be less likely to send small parts into black holes. If you have a digital camera, taking pictures as you go can be a life saver. Fetch yourself a can of spray carb cleaner. Might want to fetch up stainless allen screws for the bowl and diagphram cover.



    Completely disassemble the carb per the written instructions. Label all the pieces. Inspect all rubber and plastic pieces for wear, hardening, splits, etc. Order what you need.



    Clean with carb cleaner and compressed air, and a piece of straw or soft wire if necessary, and inspect all metal pieces, one at a time. Most likely all will be good unless someone ape-handed the parts.



    Might as well replace all the old fuel and vent lines, too. They've probably lost their pliability by now and can lead to a host of vacuum and fuel leak problems.



    Put the carb back together, check the float level, add the washer under the needle and a bigger main jet, and set the pilot screw about 2 turns out as a start.



    Enjoy.




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  5. #4
    Junior Member DBuck42's Avatar
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    Quote Originally Posted by pmtg View Post
    This sticky is for the carb you have: https://tw200forum.com/index.php?/top...dentification/



    First off, no bike came from Yamaha that didn't idle or would die when giving it throttle. Which means you have more going on in the carb than just needing more fuel from a larger jet and needle shim. Not trying to sound mean, just putting that out there



    Make sure the tiny o-ring that sits under the cover on the top of the carb is correctly seated. If you pulled the slide out of the carb then this could have lost its location.



    Back to the sticky, the fifth picture down shows a "pilot screw plug". Remove that plug (6th picture shows one of many ways to remove it), remove the pilot screw and clean it, as well as it's passageway. That circuit is what allows the bike to idle, when clogged it won't flow fuel and the usual indicator of this is having to use choke to keep it idling. This, of course, is provided you clean the pilot jet well...it's a tiny orifice so it doesn't take much to gunk it up.



    You cleaned the main jet and the needle, but sounds like you missed the emulsion tube/"main jet holder" as seen in the sticky's 2nd post, 4th picture. You can see it's just threaded in. Make sure that's cleaned up too.



    Make sure throttle cables are installed and adjusted correctly.



    Make sure the air cleaner is clean and there isn't a mouse nest in the intake.



    Last note, with the bike sitting for 5 years the carb needs a THOROUGH cleaning. Spraying carb cleaner on everything then some compressed air won't suffice. Chances are everything is CRUSTY with old gas residue. That needs a long soaking and/or abrasive action (sometimes I cut a piece of wire off my wire brush and use that for running through the jets). If you have an ultrasonic cleaner or have access to one, that'd be the cat's meow. Only have heard great reviews.
    Thanks for the reply PMTG. It was very helpful to better understand my issue. I have remove every screw and attachment possible on the carb, polished and clean each piece with Gum Cutter 2+2, sprayed the Gum Cutter all over and through the small passageways of the carb body. I then reinstalled everything and rechecked the diaphram just in case. I broke the main jet so I have not been able to test it yet. I order the 128 jet from Boat.net. Not sure when I will receive the part since the order said the delivery date is ETA. I will let you know what happens once I get the main jet in and the carb installed. Thanks again for your quick and informative reply.



    Dennis

  6. #5
    Junior Member DBuck42's Avatar
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    Quote Originally Posted by qwerty View Post
    Complete rebuild. I hope you've the time to do it right the third time.



    Fetch yourself a big cake pan and line the bottom with several layers of paper towels. Work over the cake pan. When you drop the odd small part it won't be as likely to bounce off into a black hole. Fetch yourself a couple muffin tins to organize the parts. Little slips of paper identify the parts. Fetch yourself a main jet and a little washer to fit over the needle. Print off the carb overhaul instructions from the free online maintenance manual and the parts blow-up from the parts manual. Study both well before attacking the carb. That way you'll be less likely to send small parts into black holes. If you have a digital camera, taking pictures as you go can be a life saver. Fetch yourself a can of spray carb cleaner. Might want to fetch up stainless allen screws for the bowl and diagphram cover.



    Completely disassemble the carb per the written instructions. Label all the pieces. Inspect all rubber and plastic pieces for wear, hardening, splits, etc. Order what you need.



    Clean with carb cleaner and compressed air, and a piece of straw or soft wire if necessary, and inspect all metal pieces, one at a time. Most likely all will be good unless someone ape-handed the parts.



    Might as well replace all the old fuel and vent lines, too. They've probably lost their pliability by now and can lead to a host of vacuum and fuel leak problems.



    Put the carb back together, check the float level, add the washer under the needle and a bigger main jet, and set the pilot screw about 2 turns out as a start.



    Enjoy.
    Thanks for your quick reply Qwerty. It sounds like I have completed the task as you have instructed. Just waiting for the main jet. All passages were sprayed with Gum Cutter 2+2 with the small straw attached to the can. Ran small wire through all passageways and cleaned multiple times with Gum Cutter. The carb looks brand new now. The washer I put under the needle is very thin. If I am installing a 128 main jet how thick do you recommend the washer be? Do dealers locally usually carry main jets that will work. I would like to check to see if the carb clean will work. If not, where should I look for air/vacuum leaks? Thanks again for all your help!



    Dennis

  7. #6
    Junior Member DBuck42's Avatar
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    I just looked at the carb. and realized that the only screws I did not remove were for the coasting enriching cover. I found after removing it that the rubber diaphram is cracked pretty bad. Do you think this would cause the problem I am having, only idles at full choke and the engine stalls with slight throttle?



    Dennis

  8. #7
    Banned qwerty's Avatar
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    I've never seen a bad coasting enricher part so I've no idea what difference it could make. Order a new part just for peace of mind.




  9. #8
    Junior Member DBuck42's Avatar
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    I was able to get a 130 main jet today so I got the carb back on. It started with full choke, will idle at 1/2 choke, fast throttle increase it stalls, blurbing the throttle I was able to get WOT and it ran very smooth. Still will not idle with out chock and initial throttle makes it stall. Still sounds like the pilot is having a problem. WOT works fine so I guess the main is OK. If main is OK and Pilot is not, is it reasonable to assume there is not an air/vacuum leak? Should I take the carb apart again and do a bath clean? Are there replacement parts for the pilot that may correct the problem? Every place I can see is clean as new, carb cleaner sprayed and thin wire through all passages. How sensitive are these carbs.? Thanks again for all the help.

  10. #9
    Banned qwerty's Avatar
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    If you are absolutely, positively sure the carb is 100% right, and it is still running lean, I'd suspect a vacuum leak.




  11. #10
    Junior Member DBuck42's Avatar
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    What does the brass tube that comes out at an angle right next to the main jet due? I used a sharp straight pin and pushed it into the tube. It felt like the pin went into some very hard rubber and would only go in the tube about as deep as the visual part of the tube. Should this tube be completely clear? If so, it seems like I will have to some how dig this rubber-feeling compound out.

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