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Discussion Starter #1
Just picked up a used 2012 TW200 for $2,250 and was told everything was perfect. Got it home and after warmup I noticed that the bike would stall or mis when moving the throttle just above idle while driving down the road. Full throttle and response seems normal, just the slight twist in throttle produces the intermittent stall/misfire. Previous owner mentioned he once took it into the shop because it would not start and they told him it was bad/old fuel and took care of the issue. After that he swore he never left bad fuel in the tank. Seller sold the bike because he no longer gets time to use it.

So...should I ditch all the current fuel and try some fuel treatment? Any recommendations for brand of treatment. Or should I start somewhere else?

Thanks for any help and having this website up.

John
 

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I recently had success with a Sea Foam treatment. My bike had sat with fuel in the tank for who knows how long. I used more than recommended by the manufacturer, approximately 3 oz/gallon. I then went for a 5 minute ride and parked my bike for about 3 days due to rain.

The next time it was started, the rough idle and generally poor performance had greatly improved. It's not a substitute for a proper carb cleaning, but for $12 a can, it couldn't hurt to try.
 

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Dump fuel - add fuel - and as above, add seafoam

Don't expect an instant miracle, run a tank through it

If that doesn't work, report back and we'll make other "suggestions" - but as the last poster said, "for $12 a can, it couldn't hurt to try."

Welcome to the cruise .... ;)
 

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If not a "miss" due to a spark issue, it is going lean when throttle is first opened.
Possible issues include:
1. Mixture screw not far enough out, typically 2 1/2 turns from gentle seat
2. Pilot jet slight build up of crud
3. Needle too lean
 

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I should add, I had the "miss" at idle and sometimes while riding. I thought at first it was an electrical issue, but I read these forums and got some members input which led to the mixture screw adjustment, as SportsterDoc said 2.5 turns out.

The popping under decel was gone, and much better all around ride-ability. The 2.5 turns out and a good dose of Sea Foam has made my bike so much better. It only cost me $12! Hate to think what the dealer would have charged.



*mixture screw not idle
 

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Discussion Starter #7
Thanks for all the feedback. I will give this a shot. BTW, the bike does "The popping under decel" like the last post.

I will let you guys know how it goes.
 

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There will most likely be either a brass or aluminum plug/cap covering the mixture screw. I threaded in a small 3/4" screw, then slipped some needle nose pliers over the screw, and tapped the pliers with a small hammer to get the cap/plug free.

Good luck and have fun.
 

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To augment TeeDoubleUTwoHundred's comments:
Usually drilling the cap with a 1/8" drill bit will free the cap as the drill is about to break through.
Otherwise a sheet metal screw will grab the cap to spin out the cap or allow wiggling with pliers.
 

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If not a "miss" due to a spark issue, it is going lean when throttle is first opened.
Possible issues include:
1. Mixture screw not far enough out, typically 2 1/2 turns from gentke seat
2. Pilot jet slight build up of crud
3. Needle too lean
I had the exact same symptom; just coming off idle, the motor had a flat 'dead' spot. I added 2 shims to the needle and upped the pilot jet. Problem isn't there any more. I do have a very slight dead zone at 3000rpm when the throttle is maybe 1/8th of a turn off idle. I imagine it's the needle, but raising it doesn't fix it. I either need a different taper on the needle or an over all smaller diameter on the needle to cure that portion of the throttle curve. I don't know of any other needle profiles that work for this carb or I'd try 'em.
BTW, I tune my idle fuel screw to 2 turns out. Past that point, no effect. Less and it's lean and does a lean 'pop' when chopping the throttle coming down from 5K rpm. I'm guessing a size up on the pilot would 'fix' that, but it's not a performance issue I want to worry about. Besides, a larger pilot jet burns more fuel and would affect my range on a tank of gas.
 

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Discussion Starter #12
I know I was suppose to be patient and run at least a tank of Sea Foam through the bike but still have the issue after driving about 80 miles. I will wait a bit more but wanted to share a picture of my spark plug and what the piston looks like to make sure I am not too lean. I have not made any carb adjustments yet.

Thanks for the support!

John

Spark plug.jpg

Piston A.jpg

Piston B.jpg
 

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Discussion Starter #13
Bump...

Still having cutout/stalling issues after using Sea Foam but seems a little better or I am just dealing with it. It's annoying because when I just want to cruise at a very low throttle setting the bike jerks when the cutout happens.

Please let me know my next troubleshooting step.
 

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Bump...

Still having cutout/stalling issues after using Sea Foam but seems a little better or I am just dealing with it. It's annoying because when I just want to cruise at a very low throttle setting the bike jerks when the cutout happens.

Please let me know my next troubleshooting step.
Post 4
Has the mixture screw position been checked?
That is the first thing that needs to be done to the newer extremely lean models.

If that does not solve the problem, then check the the pilot jet orifice is perfectly round...no crud in it.
 

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Discussion Starter #15
I just installed a new carb for $40 from Amazon and the problem went away. (Partman Carburetor Carb For YAMAHA TW200 TW 200 2001-2017 200 TRAILWAY) I will keep the old one as a spare. Took the old one apart and it looked clean although this was in the float IMG_9448.jpg :) Should I install a fuel filter to keep junk like this out?

So happy to have a smooth throttle response at low RPM now, no longer have fear taking turns now knowing the bike is not going to cut out.

Thanks for all the help! When I have time I will make those adjustments to the old carb and see what happens so I know I have a good spare.
 

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As a point of curiosity, what was the mixture screw setting on the original carb?
 

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Discussion Starter #17
If I had the right screw, it was only 1 turn out. Previous owner said a repair shop did some work to the carb when he let it sit too long. The altitude there I believe is 2000'

I live in So Cal with about 100-500' altitude. How many turns should you use as you go up in altitude?
 

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If I had the right screw, it was only 1 turn out. Previous owner said a repair shop did some work to the carb when he let it sit too long. The altitude there I believe is 2000'

I live in So Cal with about 100-500' altitude. How many turns should you use as you go up in altitude?
For up to about 5,000 feet or so, 2 1/2 turns. A little less with increase in altitude.

If the screw on your original had been opened from factory setting, you may have solved the issue...but $40 is a reasonable fix.

See post one of this thread: https://www.tw200forum.com/forum/general-discussion/32346-introduction-2.html
 

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Discussion Starter #19 (Edited)
I noticed the choke on the new carb really has no affect on the throttle when pulled all the way out or half way. Is there an adjustment for this too or did I get a bad carb from Amazon? Bike runs great and does not seem to need a warm up anymore.
 

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Difficult to comment about choke / enrichener as it is not a factory carb.
Do you have any documentation for the Amazon carb?
If not, close-up photos of the linkage?
 
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