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TTR-125 pilot screw and help

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I have been reading this forum and searching like crazy for info. So everyone seems to say the bike needs to be re-jetted.

I live around 5000 ft above sea and will ride anywhere from 5-9000ft. So would going to a #17 and 110 main hurt the bike? From what I can get the higher you go the lesser of the jet's you want.

Also I am going to replace the spark plug on the bike. It was really black after pulling it out. Is this a sign of lean or rich?

How can I tell if the bike is too lean or too rich? Also like I posted in a previous thread the bike stalls whenever I stop or slow down hard.

With my altitude do I want it to run rich or lean? Lean means not enough gas right?

My pilot screw was set at 3 turns out. I just bought this bike brand new last april so either that is where the factory had it set or the person who built the bike set it there. Is 3 turns too much? That service manual says 2 1/2 to 3 1/2 turns but I am not sure cause most on here say start at 2 turns out.

Well any info will help cause my altitude seems so different then what all you guys are running. Maybe my jets are ok being how high up I am. Its an 04 TTR125l no electric start.

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It was really black after pulling it out. Is this a sign of lean or rich?
Too rich.

http://www.boschusa.com/images/SparkPlugFaces.pdf

Lean means not enough gas right?
Right
Is 3 turns too much? That service manual says 2 1/2 to 3 1/2 turns but I am not sure cause most on here say start at 2 turns out.

I'd say yes since you had black soot on your plug. Does the soot knock off easy with a wire brush?
Well any info will help cause my altitude seems so different then what all you guys are running. Maybe my jets are ok being how high up I am. Its an 04 TTR125l no electric start.
I'd say to screw that pilot screw back in then back it out to 2 turns. If you're about to change plug anyway; change the plug and ride the bike first, BEFORE making any changes. I don't know how black your plug is but if it's been in since last April, clean it at the very least before you start making adjustments. Then, with the new or clean plug in, ride it around for 5-10 minutes and see what your plug looks like. If it's black, then you need to turn the screw in some more.

The 125's apparently come lean from the factory & someone may have turned the pilot out to 3 turns knowing this, but not thinking about your riding environment. Last...be patient with the jetting! I've been adjusting my carb since this last weekend and don't have it perfected yet. It's much better than it was though thanks to some help I got on here. Hope this helps. :banghead:

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At your altitude you may actually need to go down on the jets. It really all depends on how it runs.

If you are idling too low and the idle screw won't raise the idle for you, it's probably because the fuel screw is out too far and it's too rich at idle. I had that happen to me just last weekend. It kept idling low and stalling and the idle screw had no effect, so I tried going out further on the fuel screw thinking that was the problem and it kept gettng worse. I finally seated the screw and backed it out 2 turns and all of a sudden the idle went up and started responding to the idle screw. I took a few test runs and kept adjusting the screw until I got a slight popping on deceleration, then I adjusted it so the popping just stopped and left it there. The bike ran great the rest of the day.

I would try going in on the pilot (fuel) screw a little and see if that helps the stalling/low idle/bogging problem first. Try 1 1/2 to 2 turns and see if it gets better.

It won't hurt to get a new plug either. I keep hearing they can partially foul and cause a multitude of problems.

The only reason to rejet a bike is because it is running like crap. If you can get it running good on the stock jets, which at your altitude (higher altitude=less oxygen in the mixture which makes the bike's mixture richer) is highly possible, then those are the jets you need. The only real way to know is to change the jets one at a time and see what it does to how it runs. Only after you create a richer mixture then a leaner mixture and see what it feels and sounds like will you know how your bike at your altitude and temps needs to be jetted.

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