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Old 04-06-2010, 06:29 PM
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Default 04 Yz125 Carb adjustment help

What does everyone think is the best way to adjust a carb? I mainly do trail riding and I would like to not foul plugs.

Last edited by evoman; 04-06-2010 at 06:44 PM.
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Old 04-06-2010, 10:57 PM
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Before you even try adjusting a 6 year old caburetor, go to the knowledge base here and find a post by Faded which will show you better than any manual I have how to set the float. If you are worried about plugs, you can get about 80% of your worries erased if you follow his instructions.

Different people take different paths to the same place when it comes to adjusting and jetting. After you read his post and make a copy of the pictorial jot down any questions and come back.
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Old 04-14-2010, 11:01 PM
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I agree with ossagp. Set your float height with faded's guide.

Then read Spanky's jetting guide to get a quick jetting education.

Then describe in detail how your engine is behaving under what riding conditions.

With that in hand, we can offer better help.

Ian
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Old 04-29-2010, 09:07 AM
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My float level is good and I read spankys jetting guide. It said that turning the air/fuel screw in makes it richer. I thought it was the opposite. If that's the case do you think if I turned it out to lean it up some that could fix it? When I bought it it was at 1 1/2 turns out and I moved it to 2 thinking I was adding fuel. I'm running the gas at 32:1 and I'm fouling a plug an hour. The bike is stock aside from a fmf pipe and silencer. It runs great untill after an hour it sputter and dies.
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Old 04-29-2010, 08:17 PM
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Are you running stock plugs or some cross over champion cheapy?
What are the numbers on the jets?

Yes, on a 2 stroke turning the air screw out leans the first 1/4 and turning in makes the first 1/4 richer.

Try moving your clip up one notch on the needle. This will drop the needle further down into the main jet and lesson the amount of fuel in the middle of the throttle travel. Consider also maybe stepping down on your pilot jet one step at a time until it cleans up. If you have the proper pilot jet in it, with the air screw at 1 1/4 to 1 1/2 it should just barely idle.

If it has the stock #30 pilot jet in it, step down to the 27.5 first and then the 25 if you have to.

I think that with the pilot stepped down a tad and the clip raised one notch you should be in the ball park.

Ride safe.

Ian
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