2003 YZ250F popping on decelleration???

O

owenlo

Member

Oct 28, 2001

214

0

• Dec 22, 2002

• #1

Just broke in my 03 yz250f yesterday and I noticed a popping sound on decelleration everytime. It also seems like the power dosen't come on till about half throttle. It was 55 degrees out at about 3000ft elevation and 60% humidity. Any suggestions. The bike is bone stock. Have not touched a thing.

Obie#723 ;)

 

CaptainObvious

Formally known as RV6Junkie

Damn Yankees

LIFETIME SPONSOR

Jan 8, 2000

3,331

1

• Dec 22, 2002

• #2

Is the popping coming from the exhaust like backfiring? This is indicative of lean jetting. Your lack of low-end power would support this.

Gary

 

O

owenlo

Member

Oct 28, 2001

214

0

• Dec 22, 2002

• Thread starter
• #3

Sounds just like backfiring out the exhaust. Think I will try playing with the Air Screw a little and if that don't help it i'll go up one size on the pilot jet and see if that dont clean it up. Thanks Junkie!!!

Obie#723 ;)

 

M

MXP1MP

Member

Nov 14, 2000

1,845

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• Dec 22, 2002

• #4

I went to a 45 pilot and changed the needle to clip position 5, popping reduced almost completely when still cold, when warmed up it is gone. The richer setting has helped with starting. It has given it more snap in the throttle response. I think for more low end snap it has to come from lowering the gearing.

 

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MikeyG

Mod Ban

Nov 28, 2002

100

0

• Dec 22, 2002

• #5

Originally posted by owenlo
Think I will try playing with the Air Screw a little and if that don't help it i'll go up one size on the pilot jet and see if that dont clean it up.

Click to expand...

It's not an air screw, its a fuel misture screw. It does the opposite of what an air screw does for a 2 stroke (in is leaner, out is richer). Trying to tune it the oter way will make your problem worse. Good Luck

 

V

vancerd

Member

Oct 29, 2002

10

0

• Dec 22, 2002

• #6

O.K. I went with my buddy yesterday to pick up a 2002 250F. It had a big hesitation off idle (like a 2-stroke when the air screw needs to be turned in). Of course the air screw was the first thing we looked for. WHERE IS IT. Is it that brass, hex head screw at the very bottom of the carb on the left side?

 

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Matt90GT

Member

May 3, 2002

1,517

1

• Dec 22, 2002

• #7

There is no AIR screw on a 4 stroke. It is a fuel screw. It is located on the engine side of the carb, usually centered under the neck.

 

O

owenlo

Member

Oct 28, 2001

214

0

• Dec 23, 2002

• Thread starter
• #8

Thanks all!!!