ttr125 top end sputter, bigger sprocket???

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May 17, 2000
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#1
i have cut the airbox open,uncorked the exhaust,welded a downward s.s. tip on the end cap,,(almost sounds as good as the 250f!! ) i have 117.5 main in until my 115 gets here, it runs great, very good response, but on top end i get this "sputter" almost like my rev limiter on my 250f but these bikes dont have one do they??? what is it , how to get rid of it,and is it harming anything??? also what rear sprocket is everyone running???? stock on the short version is 49,,,im thinking of a 52,,,any thoughts or where to get one??? these free mods make it rip for what it is....thanks cw :confused:
 
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#2
Not sure about the sputter, but as for sprockets many of us have stepped up the front sprocket one tooth. Many places sell them, (www.xronly.com).

this works well for now. I am not sold on the larger sprocket just yet, but then it is my girlfriends bike and my 200+lbs is probably alot for the little bike to pull around.

Mike
 
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#3
I thought that was a rev limiter as well until this past weekend. I was informed there want one on the ttr125 and I was floating the valves.
 

Vic

***** freak.
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#4
You're likely too rich on the main. My bike is similarly modified and I've gotten the best results from a 110-112.5 . Your fuel might require something different. I have a 14t countershaft sprocket and the motor pulls it easily.
 
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#5
My boy's ttr125L with similar mods, 14T sprocket, and powerol's thruster tip ended up with a 100 main. We do ride at 5000 feet and up.
 

ACS

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#6
I'm glad that others are finding out about the top end splutter. I thought that mine was the only one with the problem. If it is valve springs, Im now fairly sure it is, who makes a stronger set? I have the VISA card waiting.....:)
 
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#7
i have cut the airbox open,uncorked the exhaust,
There is such a thing as too much airflow on these little bikes. We found they were very finicky when the intake was messed with much, especially at higher (above 2,000') elevations.

Try duct taping the holes in the lid. It may make the problem go away. Then, remove duct tape until the problem returns -- this way you'll know the breaking point between not enough air and too much.