06 yfz450 won't idle: jetting

Yamaha

So I have a little bit of a problem. I have a friend that i am rejetting his 2006 yfz450 with the lid off the air box, and the baffle out of the pipe and after putting in the gytr kit amd cleaning carb the bike won't idle. I have the jetting as follows 170 main, 4th position on the needle, a 45 pilot and a/f screw 1 turn out.

I figured with the a/f one turn out I could get it started then tweak it from there.

We got everything back together and could not get it started, I turned the idle circuit all the way in and that is the only way I could get it running but it had a very fast idle. As soon as I backed out the idle screw the bike would die. What am I missing? I have never really had many jetting problems with any of my bikes and now i do a friend a favor and I can't get this thing handled properly.

Any help here would be appreciated.

Sounds almost like you have an air leak. Try posting your problem in the Yamaha sport quad forum. A lot more people read that one. Better chance of getting an answer that can help. It also helps to know what altitude you're at so we can offer better information on jetting.

Double check everything to make sure you don't have an air leak. Sometimes we all get in a rush and forget the simple stuff......it happens. When you can get it started, how does it run?

Why is the fuel screw only one turn out? I know my bike would never idle that way. Turn it another 1 1/2 turns out ( 2 1/2 turns out total) and see what happens.

The right way to adjust your fuel screw is to completely warm up the engine, set a fast idle and turn the fuel screw in/out until you get the highest idle.....then adjust your idle to what it should be. Easy as that!

Less than 1 turn means your pilot jet is too fat. More than 3 turns means your pilot jet is too lean. Backfire on decel is an indicator of a lean pilot jet.

In this case, I'd check for an air leak around the intake boot.

Sounds almost like you have an air leak. Try posting your problem in the Yamaha sport quad forum. A lot more people read that one. Better chance of getting an answer that can help. It also helps to know what altitude you're at so we can offer better information on jetting.

No air leak everything is tight. My altitude is 3000'

Double check everything to make sure you don't have an air leak. Sometimes we all get in a rush and forget the simple stuff......it happens. When you can get it started, how does it run?

I took the carb back out and recleaned it. It is running much better but kind of bogs in 2nd and 3rd gear WOT.

Why is the fuel screw only one turn out? I know my bike would never idle that way. Turn it another 1 1/2 turns out ( 2 1/2 turns out total) and see what happens.

Any carb can virtually run with a A/F screw 1-3 turns out. I have always set them at one for easy starting after doing carb work, then adjusted properly from there.

The right way to adjust your fuel screw is to completely warm up the engine, set a fast idle and turn the fuel screw in/out until you get the highest idle.....then adjust your idle to what it should be. Easy as that!

Less than 1 turn means your pilot jet is too fat. More than 3 turns means your pilot jet is too lean. Backfire on decel is an indicator of a lean pilot jet.

In this case, I'd check for an air leak around the intake boot.

Put the air lid on the airbox, get it nice and hot.....then ride it. See if it gets worse/better. Definitely the easiest way to diagnose the jetting in your situation.

Sounds like you're pretty knowledgeable with carbs, tattoart, good luck.

try the a/f mixture 2 and a half turns out

What was the root of the problem?

i had the same prob with mine..it was the tps

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