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07 crf150r jetting

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Hi,

 

I recently bought a 07 crf150r for my daughter. Wasn't running well off idle. Cleaned carb, still was having same issues. After reading many posts i replaced the stock pilot jet size (40) with a 45. Nothing changed. replaced fuel mixture screw with an r&d flexible one, same issues with fuel screw turned out 2 & 1/4 turn, had to open screw to 4 & 1/2 turn to got proper off idle response, the bike runs fine with that setting, but is it normal ? I am in south florida usually i jet lean in this location. I did not check the valves yet, will tight valves impact fuel jetting ? Should i try a size 50 pilot jet or keep the existing one ? What will cause the pilot jet to run richer ? Thanks

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Change to the '08+ needle and jetting. You'll never get it with the '07 needle.

 

+1 to what he said.  Just had to do that to my girlfriend's 07 CRF150R.  The 08 settings are below.

 

Main 138

Pilot 38

Pilot Screw 2 turns out

Needle NMQS 3rd clip (p/n 16203-KSE-601)

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+1 to what he said.  Just had to do that to my girlfriend's 07 CRF150R.  The 08 settings are below.

 

Main 138

Pilot 38

Pilot Screw 2 turns out

Needle NMQS 3rd clip (p/n 16203-KSE-601)

 

what were the bike symptoms ?

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It runs ok once it gets going. If it's idling and you blip the throttle the bike will cut out. If your smooth on the throttle it's fine but it does not respond well to quick throttle adjustments. I hear the 08 jets and needle solve this issue. 07 is too lean.

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It runs ok once it gets going. If it's idling and you blip the throttle the bike will cut out. If your smooth on the throttle it's fine but it does not respond well to quick throttle adjustments. I hear the 08 jets and needle solve this issue. 07 is too lean.

Are you sure it not an accelerator pump/circuit  issue ?? In my case, my problem is an off idle issue, the pilot jet is at 45 (am at sea level, south florida) right now and the fuel screw is 4 turn out( off idle not crisp, mid to top fine; needs to open throtle to start it while hot); the pilot jet in the 08+ is 38 ( leaner) although mine seems to want a bigger pilot ?? Will the 08+ needle affect off idle performance ??? Regards

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Are you sure it not an accelerator pump/circuit  issue ?? In my case, my problem is an off idle issue, the pilot jet is at 45 (am at sea level, south florida) right now and the fuel screw is 4 turn out( off idle not crisp, mid to top fine; needs to open throtle to start it while hot); the pilot jet in the 08+ is 38 ( leaner) although mine seems to want a bigger pilot ?? Will the 08+ needle affect off idle performance ??? Regards

I have heard, but cannot confirm, that the 150R has similar AP issues that the older 250 and 450 CRFs had.  after messing with jetting I am thinking of popping the cover and using the old o-ring trick

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Hi,

 

after a lot of trials and error,  i Replaced stock 07  jets/needle with 08. Right now runs almost perfect . Had to change the pilot from 38 to 45 though as the 38 was too lean. The only concern is that   i am using the flex fuel screw at to 3 & 1/2 turns out. Should i increase the pilot size to get around 2 turns out on the fuel screw or leave it this way.

Edited by benhurmx

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Hi,

 

after a lot of trials and error,  i Replaced stock 07  jets/needle with 08. Right now runs almost perfect . Had to change the pilot from 38 to 45 though as the 38 was too lean. The only concern is that   i am using the flex fuel screw at to 3 & 1/2 turns out. Should i increase the pilot size to get around 2 turns out on the fuel screw or leave it this way.

 

According to Eddie Sisneros, yes:

 

http://www.thumpertalk.com/topic/271735-how-to-confirm-your-pilot-circuit-setting/

 

But, also, did you notice that the '08 jetting went richer on the main and leaner on the pilot? If you have a one-step richer main jet you might try that and see how that effects the pilot screw setting and the overall running.

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