Could use some help

[Rigenie]

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.

[Miaugi]

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.

[Fred]

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.

[Rigenie]

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.

[Sthrnromr]

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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[Rigenie]

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?

[Sthrnromr]

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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[Rigenie]

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

[Ski Pro 3]

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.

[Rigenie]

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