How To Correct a Lean Condition?
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Thread: How To Correct a Lean Condition?

  1. #1
    Senior Member TeeDoubleUTwoHundred's Avatar
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    How To Correct a Lean Condition?

    Hello,

    This is my 1st post here. I just recently bought a new 2017 TW200, which is also my first motorcycle. I'm having a blast on it so far.

    The engine does run lean, though. From what I've read on this site so far, that is the way Yamaha ships them. When on decel, there is a lot of popping noises from the exhaust. I'd really like to fix that myself, rather than have to leave my bike at the dealership for how many days and $ later.

    So, just to clarify,

    1) Bike is warmed up to operating temp. and I am at 1000 feet above sea level.
    2) I'm under the bike looking up at the carb, with the top of my head resting against the front tire.
    3) Gently turn the pilot screw clockwise until it bottoms out
    4) Then turn the pilot screw counterclockwise 2 to 2.5 turns out
    5) Take the bike for a rip and see how it does

    I plan to do all the servicing and maintenance on my TW myself and this site looks like a great source of info for our bikes. I'm new to carbs, so any advice, tips, tricks, etc. would be appreciated!

    Thanks for your time.
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  2. #2
    Senior Member Dryden-Tdub's Avatar
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    Quote Originally Posted by TeeDoubleUTwoHundred View Post
    Hello,

    This is my 1st post here. I just recently bought a new 2017 TW200, which is also my first motorcycle. I'm having a blast on it so far.

    The engine does run lean, though. From what I've read on this site so far, that is the way Yamaha ships them. When on decel, there is a lot of popping noises from the exhaust. I'd really like to fix that myself, rather than have to leave my bike at the dealership for how many days and $ later.

    So, just to clarify,

    1) Bike is warmed up to operating temp. and I am at 1000 feet above sea level.
    2) I'm under the bike looking up at the carb, with the top of my head resting against the front tire.
    3) Gently turn the pilot screw clockwise until it bottoms out
    4) Then turn the pilot screw counterclockwise 2 to 2.5 turns out
    5) Take the bike for a rip and see how it does

    I plan to do all the servicing and maintenance on my TW myself and this site looks like a great source of info for our bikes. I'm new to carbs, so any advice, tips, tricks, etc. would be appreciated!

    Thanks for your time.
    So long as you have already removed the press fit cap from the adjustment location then you are correct.


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  3. #3
    Super Moderator Purple's Avatar
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    This brings up a couple of questions ….

    1) Most of us adjust that screw to improve cold starting, yet you’re still popping when warm

    1a) Most of us, find that idle jet hole “plugged” by a bit of brass, which needs removing to gain access

    2) With regards to this point, you should be looking at your bash plate

    3 – 4 – 5 – are quite correct

    The confusing bit is if you don’t find a brass plug, then someone’s already been in there – but if you do, it still sort of all makes sense

    If you have access problems, loosen both carb boots, turn carb as much as needed

    As you’re new here (you didn’t think we were going to make it easy did you) – please edit your profile to reflect location, and your signature line to reflect the year of your bike – it will save a bunch of questions later on

    Welcome to the madness …..
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  5. #4
    Junior Member Aguaski's Avatar
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    While you are working at the bottom of the carb I would unscrew the bowl and remove the main jet to see what size is in there. My old eyes need a magnifying glass to see the verily visible small stamp on the brass jet. If you are running lean it wouldn’t hurt to go up one size from whatever you have to richen the fuel.


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  6. #5
    Senior Member TeeDoubleUTwoHundred's Avatar
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    The cap has already been removed from the pilot screw. My bike is a new, left-over 2017 Canadian TW200 so I'm guessing that the dealership may have made adjustments?

    Hopefully, a few turns of the pilot screw will correct the problem.

    I will eventually re-jet the carb, probably towards the end of riding season, which is really short around here. I've only logged about 110km / 60'ish miles since getting my licence, so I need to get out and ride!

    Thanks for the advice!
    Purple, jbfla and Fred like this.
    2017 TW200 -> Hand Guards-Chain-Foot Pegs-Skid Plate-Shifter-Grips-Mirrors-Fuel Filter-Fender-Levers

  7. #6
    Senior Member Fred's Avatar
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    Welcome.
    Good sequential plan of progressive enrichment TW200.
    After the mixture screw and mild jet enlargement some like to go further with a common third change reportedly for lower elevation riders: Shim(s) under the needle if so equipped or raising the needle via a circlip if you have that style in a Canadian 2017.
    2003 TW200 "Betty Boop"
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  8. #7
    Senior Member tylermoney's Avatar
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    Welcome aboard the TW Train.

    I'm a new TW owner as well. It had been quite some time since I did more than change oil or clean my motorcycle chain, so getting back into doing all my own stuff for the TW has been a bit of a learning curve

    I worked on the lean issue as well; however, I did TOO MANY things at once. I am still working out some tuning issues overall, but the bike runs decent enough—basically I just lost some top-end speed for the time being.

    My recommendation is basically what you're doing. One step/change at a time. Do the idle/air screw to 2.5 turns. See what happens. Take it to 3 if you don't like 2. See what happens. Go to 2 or 1.75 if you don't like 3, and so on. I ended up adding a DG Slip on Exhaust as well, which will change things up a bit. If you're going to do the FMF or DG exhaust, I recommend maybe doing that prior to re-jetting, as adding the exhaust usually requires adjusting the jetting anyways.

    This forum more/less has a thread on everything, and if you're not finding it, folks are extremely helpful in trying to help figure out your problems or answer your questions. Have fun and good luck!
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  9. #8
    Senior Member TeeDoubleUTwoHundred's Avatar
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    Just an update.

    The plug was in fact still in place on the pilot screw. The plug was aluminium instead of brass on my 2017. Getting the plug out took the most time. I adjusted the pilot screw out 2.25 turns and the popping under decel is gone.

    I will ride the bike for an hour today to see how it operates and adjust another 1/4 turn if necessary. The quick rip around the block was promising. The bike seems to be smoother and more responsive.

    Thanks dudes!
    2017 TW200 -> Hand Guards-Chain-Foot Pegs-Skid Plate-Shifter-Grips-Mirrors-Fuel Filter-Fender-Levers

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