HOW TO: Rejetting your CRF150F for better power !
  • T Man
    Posts: 6
    Joined: Mon Oct 13, 2008 8:03 pm

    by T Man » Wed Oct 22, 2008 9:13 pm

    I recently bought a 2005 150F with a pro circuit T4 pipe. The seller did not modify the air box. He changed the jetting, apparently for high altitude riding, not because of the exhaust upgrade. Any suggestions for jetting or air box mods to optimize performance?
  • rocketman
    Posts: 666
    Joined: Wed May 16, 2007 2:02 pm

    by rocketman » Thu Oct 23, 2008 10:34 am

    T man and JJ, I have since sold our 150f but we finished with;
    42 pilot, bike is very lean from factory
    115 main jet
    raise the needle one by moving the clip down a notch
    pill the snorkle off, its just glued there
    put a good flowing air filter (be sure to keep it clean)!
    That should help
  • T Man
    Posts: 6
    Joined: Mon Oct 13, 2008 8:03 pm

    by T Man » Thu Oct 23, 2008 8:33 pm

    Rocketman,

    did your 150 have stock exhaust?
    are jets typically marked with numbers that I can check?

    thanks.
  • rocketman
    Posts: 666
    Joined: Wed May 16, 2007 2:02 pm

    by rocketman » Thu Oct 23, 2008 8:57 pm

    We had a pipe (DCM Alien)on the bike too, it was a free flowing pipe (Didn't care for it) your t-4 will be a better pipe! the jets are marked, the pilot on the side once removed and the main sometimes on the side or on top. I thought it was easier to just remove the carb make the changes on the bench and reinstall rather than try to change on the bike. The carb is Very easy to r&r! I was never satisfied with the power produced by this bike that is wy we sold it. It would probably climb a tree but it lacked the snap/torc on the bottom. it is a durable and dependable bike just not much power.
  • T Man
    Posts: 6
    Joined: Mon Oct 13, 2008 8:03 pm

    by T Man » Fri Oct 24, 2008 6:29 am

    Rocketman,

    good info, thanks a lot.

    my son is light weight for his age, so I am hoping the power will be sufficient for at least a year!
  • jondav123
    Posts: 1
    Joined: Fri Jan 09, 2009 12:21 pm

    Some info that I found....

    by jondav123 » Wed Jan 14, 2009 7:04 am

    HONDA CRF 150 (02-05) & CRF 230
    CRF150 - STOCK ENGINES
    Full Power Needle Kit #16012-KPT-921
    42 Pilot Jet #99103-KPT-0420
    High Elevation (above 3,000') 108 Main #99113-GHB-1080
    Low Elevation (below 3,000') 110 Main #99113-GHB-1100
    CRF150 - MODIFIED ENGINES
    Full Power Needle and 42 Pilot shown above, plus:
    110 Main #99113-GHB-1100 (std bore size hi comp)
    112 Main #99113-GHB-1120
    115 Main #99113-GHB-1150
    118 Main #99113-GHB-1180 (start point for larger cc engines)
    CRF230 - STOCK ENGINES
    Full Power Needle Kit #16012-KPS-921
    Low Elevation (below 3,000') 135 Main #99113-GHB-1350
    High Elevation (above 3,000') 132 Main #99113-GHB-1320
    CRF230 - MODIFIED ENGINES
    Full Power Needle Shown above, plus:
    135 Main #99113-GHB-1350 (start point hi elevation & lo comp 66mm piston)
    138 Main #99113-GHB-1380 (start point lo elevation & lo comp 66mm piston)
    140 Main #99113-GHB-1400 (start point for hi-comp 66mm & other mods)
  • RacerX-V2
    Posts: 2
    Joined: Tue Feb 24, 2009 7:54 pm

    by RacerX-V2 » Tue Feb 24, 2009 7:59 pm

    Great info here guys, thanks.

    Question, can anyone tell me if the pilot jet on a 230F will fit the 150F? Both are '03's, and the power-up kit I bought back in '03 for my 150F never came with a bigger pilot (it really needs it for sure), which is still stock at a 40.

    I picked up a 230F, and am going to do the power-up kit for it, and will buy the proper pilot for the 150 if the one from the 230 doesn't fit. Anyone?
  • RacerX-V2
    Posts: 2
    Joined: Tue Feb 24, 2009 7:54 pm

    by RacerX-V2 » Tue Feb 24, 2009 9:57 pm

    They will fit. They are interchangable.

    Just what I was hoping to hear without pulling them both apart to find out. Mucho gracias A.S.
  • denbsteph
    Posts: 9
    Joined: Thu Apr 15, 2010 6:18 pm

    by denbsteph » Sat Apr 17, 2010 6:27 pm

    Greetings! New to the CRF world, been riding since 1976, first bike Z-50. I have owned, 1974 cr 125, 1982 kdx, ltd 440, nighthawk s, yzf 600, currently own a FZ1 and little red, 2006 crf 150F.

    Enhancements:
    Power up kit, 108 main, 42 slow jet. I have the other parts but not in, can't seem to figure it out.
    FMF Q-4 pipe
    Uni two stage filter

    My question is: I bought the power up kit, replaced the Jets, had the main 115 in but it was slightly popping and bogging in the upper gears. meaning when I was puting around in 3rd,4th gear I would get on it,it would bog,pop
    clutch it get a pretty good midrange pull out of it, but top end seemed to flatten out.

    Put the 108 main in, no pop, no bog but not a good pull. I have not yanked the air box open because I like to cross creeks.

    Question is: How do you get the throttle spring out to check the clip?
    (I believe the CRF store took me for the carb parts, meaning I have two items I didn't need,or are these items necessary to complete the power up kit?)
    I bought the whole carb kit, fuel screw and power up needle.

    Besides the fuel screw, is the power up needle stock? Again, how do I get it out to replace it?

    Where is the fuel screw located? I have the tool to remove it, just need to find it.

    Need some help from the motor heads, thanks Dennis
  • User avatar
    mr 347
    Posts: 121
    Joined: Tue Nov 10, 2009 8:16 am

    by mr 347 » Thu Jul 15, 2010 10:28 am

    I just went and got the JETs and needle fr this bike. He did not give me the slow jet. Do I need the slow jet?
    09 450x
    06 250x
    06 150f
    04 trx 400
    03 xr 80
  • User avatar
    mr 347
    Posts: 121
    Joined: Tue Nov 10, 2009 8:16 am

    by mr 347 » Sat Jul 17, 2010 12:59 pm

    guess not, it runs
    09 450x
    06 250x
    06 150f
    04 trx 400
    03 xr 80
  • User avatar
    DarkCRF
    Posts: 289
    Joined: Thu Sep 23, 2010 5:24 am

    by DarkCRF » Sun Jun 26, 2011 6:04 pm

    What about the 2011 model...still like 06+ bike ?
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    crfsonly
    Owner
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    Joined: Thu Apr 01, 2004 3:45 pm

    by crfsonly » Mon Jun 27, 2011 2:23 pm

    mr 347 wrote:I just went and got the JETs and needle fr this bike. He did not give me the slow jet. Do I need the slow jet?


    the slow jet, or pilot jet, affects starting, idle and off-idle performance. if you are having a hard time starting, rough idle or bogging off idle you should look into the pilot jet.

    ken
    OEM Parts for Honda - Yamaha - Suzuki - Kawasaki: http://yeltrik.com
    _________________
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  • User avatar
    crfsonly
    Owner
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    by crfsonly » Mon Jun 27, 2011 2:23 pm

    DarkCRF wrote:What about the 2011 model...still like 06+ bike ?


    yes...same bike.
    OEM Parts for Honda - Yamaha - Suzuki - Kawasaki: http://yeltrik.com
    _________________
    CRF Parts and Accessories: http://crfsonly.com
  • James Addiction
    Posts: 10
    Joined: Sun Oct 24, 2010 7:50 pm

    by James Addiction » Mon Jun 27, 2011 4:49 pm

    I followed the instructions exactly. We live at about 2200 ASL and we may get up to around 4500 feet while riding. When the instructions say to put the clip on the needle four from the top, I'm guessing it meant four from the blunt end.

    This made the bike run horrendously rich and it would exhibit what a lot of folk here saw, that it hesitates on first throttle twist, and at high RPM it chugs and lags, and the spark plug gets dark and wet.

    Right now the clip is two notches from the blunt end and it's working amazingly. This modification, coupled with three more teeth on the rear sprocket, has made it a whole new bike. It's a trail-riding dynamo.

    I think this is my first post.

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