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Discussion Starter · #1 ·
so...what other possibilities are there on the tw200 causing sputtering, backfire, rough idle, etc. besides the carburetor? electricals? it may still be the carb but like i have said before it has been cleaned 3 times, needle and seat replaced, 117.5 main jet and 2 and 1/2 turns out on the mixture screw. the engine and valves are very nice. it is a 1987 so im guessind its an electricasl issue. i took in the ignition coil and the tested it and said it was excellent. im thinking about taking it in to have them look at it but i was wondering if there is anything common that it most likely would be?

thanks in advance,

Nick
 

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From what I've read, the 87 is notorious for CDI/electronics issues. I'll bet part of that is because the parts are 24 years old.



I've also heard of people accidentally shorting the wires when changing the front sprocket. That's something you could check quick and easy.
 

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Did you check the carb boot for cracks like was mentioned in your other post?? That'll lean out your mixture and causes issues.



You need fuel and enough of it. If you've cleaned the carb 3 times, and each time was thorough, then you can eliminate lack of fuel, and with proper jetting you have enough.

You need air from the correct source. If your filter is clean and you don't have cracks in the carb boot (bad source of air) then you only have one thing left,

You need spark and at the correct time. Just because you get spark at the plug doesn't mean it's sparking at the correct time in the compression stroke.



I'm not familiar enough with the stators and its pickup on these bikes, could it have loosened up and slipped off its timing mark?? Or are they pinned in a single, known location??
 

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Myself and others have tried to steer you into methodically solving your bike's issues. At this point you're just shopping for easy answers.



You're in over your head. Time to get familliar with a multimeter or pay up.
 

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I thought you took it in to yamaha for electrical diagnosis.



Can you take a youtube video of you starting it, at idle and reving so we can see and hear the problems in relation to throttle position- idle, reving & wot. As I said before it is tough to solve a problem over the internet without going through a methodically step by step procedure. Help us help you
 

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Did you check the carb boot for cracks like was mentioned in your other post?? That'll lean out your mixture and causes issues.







I'm not familiar enough with the stators and its pickup on these bikes, could it have loosened up and slipped off its timing mark?? Or are they pinned in a single, known location??


The static timing is fixed and can not move, the CDI controls the advance curve and can not be "set" incorrectly. This eliminates human error.



But my best guess is still an air leak at the rubber manifold.
 

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so...what other possibilities are there on the tw200 causing sputtering, backfire, rough idle, etc. besides the carburetor? electricals? it may still be the carb but like i have said before it has been cleaned 3 times, needle and seat replaced, 117.5 main jet and 2 and 1/2 turns out on the mixture screw. the engine and valves are very nice. it is a 1987 so im guessind its an electricasl issue. i took in the ignition coil and the tested it and said it was excellent. im thinking about taking it in to have them look at it but i was wondering if there is anything common that it most likely would be?

thanks in advance,

In my experience with 2 87's if the cdi is bad it will idle, but wants to stall when you give it gas. Unless you unplug the brown wire then it will run terribly, but will get you home. A pinched wire from the stator side will make it run bad also. Nick
 

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Discussion Starter · #18 ·
well, the dealer called. its not an electrical problem at all. he said some of the float boal o-rings were expanded. not sure if that means the choke o-ring too...? but the pilot jet was pretty clogged. can this cause the sputtering/backfires that i was getting all along?
 

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Expensive lessons are sometimes best.



Glad you got it fixed, but I needn't remind you that you came in here looking for advice after supposedly "cleaning" it yourself muliple times.



Just sayin'.
 
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