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Discussion Starter #1
Hi, owner of two 2017‘s. One for me and one for my son. Bought them off the same guy, but one had the fuel mixture plug removed and the other one didn’t. The one that had the screw removed accelerates very quickly out of first and second. I don’t know what they did. Any suggestions? This one is for my son, so all advice is welcome. I have adjusted the fuel mixture screw and that didn’t work, checked the chain and that is fine, throttle play is fine and clutch play is fine. I just joined today, so thanks everyone for forming this thing. Hopefully I can be of assistance to someone else in the future.
 

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Hello and welcome to the forum and congrats on the two new to you T-Dubs! Once you remove the fuel mixture plug (if we are talking about the same thing), the standard procedure is to turn the adjustment screw in (clockwise) until it seats and then back it out 2-1/2 turns. Common hack for the TW200.
 

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Welcome!
Sounds like carburation.
PLUG removed, not screw removed on the better running bike, correct?
You adjusted the mixture screw on the poorer running bike after first removing it's plug that blocks access to the mixture screw, correct?
While the adjustment ideally is an iterative process to find the optimum setting we typically recommend two, to two & and half revolutions of the mixture screw out from fully seated for near sea level operation.
Some will advise trying to get carb running better via SeaFoam solvent, new pilot jet, ultrasonic cleaning, etc before making any changes in jet size or other alterations. Any of these approaches are good, all are trying to get you a good clean baseline to progress from ( if necessary, these basics solve most issues)

EDIT: Ooops, Maugi beat me to it with the good word and good advice.;)
 

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Thank you for the replies. The one with the fuel mixture plug that was still in runs as it should. The one that was missing is the one that is running fast. You give it a little gas and you almost feel like you’re about to pop a wheelie. I’m guessing because the plug was removed the previous owner did some thing to that one. I took the plug off the other one today and set them both at 2 1/2 turns, but the one still accelerates in first and second gear way more aggressively.
 

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Thank you for the replies. The one with the fuel mixture plug that was still in runs as it should. The one that was missing is the one that is running fast. You give it a little gas and you almost feel like you’re about to pop a wheelie. I’m guessing because the plug was removed the previous owner did some thing to that one. I took the plug off the other one today and set them both at 2 1/2 turns, but the one still accelerates in first and second gear way more aggressively.
I would check the sprocket sizes and compare them.


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Discussion Starter #6
Great call on the sprockets. He did increase the size of the front sprockets slightly, but did it for both. Strange, right? The only thing I can think of is that he put a different jet in there when messing with the carb?
 

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Great call on the sprockets. He did increase the size of the front sprockets slightly, but did it for both. Strange, right? The only thing I can think of is that he put a different jet in there when messing with the carb?
Double check the rear sprockets. Could be jetting but I doubt it would be that dramatically different.


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Discussion Starter #8
I’ll definitely check the rear sprockets as well. Thanks. Once both bikes are at 35+ miles per hour, they run identically.
 

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Consider flushing the fuel tank and starting with fresh fuel. There's a drain screw on the carb as well. Maybe look in the tank once it's drained with a flashlight to see if the petcock filters are plugged at all. Check spark plugs too. Fiddle with the choke on both to see how that affects things.
The only improvement I've witnessed with any adjusting is with shims on the carb needle. It's not easy to check, so I don't recommend doing that just yet. Can you get in contact with the last owner and ask him some questions? Maybe he can provide some insight.
 

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Discussion Starter #10
I will try flushing the tank. Again, the only difference between the two bikes is in first and second gear. The one with the carburetor fuel mixture plug missing accelerates much faster than the other one. I’ll try anything at this point in an effort not to have to replace the carburetor
 

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" The one with the fuel mixture plug that was still in runs as it should. The one that was missing is the one that is running fast"

As it should? So trying to slow the fast one with the missing plug down to normal TW standards?:p -Just teasing, Had to go for the low hanging fruit.

Carbs could always be removed, disassembled side by side, differences noted, then reassembled and installed but swapped into opposing chassis. That could be enlightening or confusing depending on the results. It would answer many a question as to possible causes of the disparity.


 

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Congrats and welcome. I am not sure I understand your problem. Accelerating faster in first and second sounds like a good thing. If you mean the rpms don’t drop between shifts that is a different problem. Nevertheless you most likely won’t need to replace the carb just fix it if not correct tune or clean.
 
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Discussion Starter #14
All of you have been incredibly awesome and very helpful. I went through the whole bike today and convinced that the person before me changed the jets on the carburetor on one but not the other....or it’s just dirty. Having two of the same exact bike makes it somewhat easy to troubleshoot, but I will be leaning on you guys again in the near future, I’m sure. Thanks!
 

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Welcome to the forum. Good to know whatever the PO did made such a noticeable difference. I think we’re all waiting to hear what jet sizes or other changes were made. Congrats on your new bikes and it’s awesome you get to ride with your son.
 

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If they were my bikes rather than speculate I would find out.
I would pull both carbs, disassemble them side by side, note jet sizes, degree of cleanliness, then replicate condition on the weaker bike if any disparities were noted. If no noticeable differences are observable then upon re-assembly I would install each carb in the other bike and then test run both. This would then address any differences in chassis set up, final drive gearing, parasitic friction losses, wheel bearings, brakes, etc.
Then I would be more accurately informed , not only of the mentioned difference in initial acceleration but would also understand the bikes, their disassembly and operation that much better. If they are new to you then I think it helps to better understand them today so as to help with tomorrow's problems. Otherwise one can become dependent on a mechanic's , or forum's opinions rather than your acquired knowledge. Never too late to learn mechanical skills.
But then again I am a guy who likes to take things apart to better understand the world around me.
 
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