Jetting database for Honda CRF's
  • User avatar
    paul turner
    Posts: 7578
    Joined: Thu Sep 22, 2005 9:03 pm

    by paul turner » Tue Sep 28, 2010 6:36 pm

    Yes, at that point you shoulda installed a 45 pilot jet.
    If you ain't crashin', you ain't ridin' :-)
    Image
  • gator
    Posts: 15
    Joined: Mon Jul 26, 2010 10:36 am

    by gator » Tue Sep 28, 2010 10:45 pm

    Thanks Paul. Don't know what you mean though when you say "at that point". With the 165/42 and only the snorkle out it runs great at 2 turns out. Are you saying try the 45 pilot now or should I have tried it with the air box opened up? 8-[
    "Its better to burn out than fade away"
  • gator
    Posts: 15
    Joined: Mon Jul 26, 2010 10:36 am

    by gator » Mon Oct 04, 2010 7:33 pm

    Tried the 45 pilot, both ways, not so good. 42 is the ticket with that ncvs needle. Although the 165 main was VERY good, I tried a 170 and uncovered some holes in the top of the air box/side vents....my goodness, Gator likey!! :D :shock: :D

    NEW SET UP

    1200 feet
    170 main
    42 pilot
    NCVS needle
    Clip in 3rd position
    Fuel screw 2 turns out
    Boyessen AP
    Snorkle removed/holes drilled in top/side vents
    Stock exhaust/baffle removed
    Stock filter/cage/backfire screen

    That is a MONSTER XR right there.
    "Its better to burn out than fade away"
  • User avatar
    DarkCRF
    Posts: 289
    Joined: Thu Sep 23, 2010 5:24 am

    by DarkCRF » Fri Oct 08, 2010 10:14 am

    Year: CRF450R 2005
    Elevation: 400 to 1500 ft
    Temperature Range: -10C to 30C
    Backfire Screen: Removed
    Air Filter: UNI
    Pilot Jet: 42
    Main Jet: 185
    Needle: JD red
    Needle Clip Position: 4th from top
    Fuel Screw Type: Moose racing
    Fuel Screw Setting: 2 1/4 out
    AP Modified: O-ring and 2.7mm rivet
    Leak Jet: 55
    AP Cover: OEM
    Exhaust Type: Bill's pipe slip on
  • JfRacing911
    Posts: 41
    Joined: Wed Jun 09, 2010 9:59 am

    by JfRacing911 » Mon Oct 11, 2010 2:25 pm

    Year: CRF450X 2009
    Elevation: 0 to 1500 ft
    Temperature Range: -10C to 30C
    Backfire Screen: Removed
    Air Filter: twin air
    airbox cover and top hacked
    Pilot Jet: oem
    Main Jet: 165
    Needle: JD red
    Needle Clip Position: 4th from top
    Fuel Screw Type: oem
    Fuel Screw Setting: 2 1/2 out
    AP Modified: no
    Leak Jet: oem
    AP Cover: OEM
    Exhaust Type: oem
  • Back2-2
    Posts: 1148
    Joined: Tue Jan 04, 2011 3:31 pm

    by Back2-2 » Mon Feb 07, 2011 8:03 am

    Here is what I ended up with and it runs absolutely perfect ! Now I love this bike ! Fires instantly, idles smooth as a sewing machine. Grunts at .0001 mph like a tracker & rips out like a 2-stroke. Damn this is one sweet / blinding fast bike ! Does not generate the heat it did stock either.
    Thanks to all the help on the CRF's only crew.

    Year: 2006 CRF450X
    Elevation: 1000-3500
    Temperature Range: 55-105f
    Smog (AIS): AZ bike - No smog equip.
    I did remove the breather line from the valve cover to the air box and made a home made breather canister.
    Airbox Modified Top: entire top and three 1 1/2" holes under Battery holder.
    Airbox Modified Sides: no
    Backfire Screen: in place.
    Air Filter: stock
    Pilot Jet: 48
    Main Jet: 168
    Needle: NCVS
    Needle Clip Position: 3rd from top
    Fuel Screw Type: Tusk aluminum
    Fuel Screw Setting: 1 1/4 to 1 1/8 out.
    AP Modified: no
    Leak Jet: stock
    Tie-Wrap mod - you guy's call it O-ring mod - Yes.
    AP Cover: stock
    Exhaust Type: stock reengineered to flow full
    Exhaust Modified: full open with 0.020 screen across end cap for spark arrester
    Pink Wire Modified: no
  • advbedouin

    by advbedouin » Mon Jul 25, 2011 5:25 pm

    Thanks to all for the great info. Mine is run mainly at sea level, but it worked great recently in the sierras at 7K'-10K' elevation.

    Year: 2005 CRF450X
    Elevation: 500-3500
    Temperature Range: 65-90f
    Smog (AIS): Block off kit.
    Airbox: 4"x5" cut out top.
    Airbox Modified Sides: no
    Backfire Screen: Removed.
    Air Filter: Twin-Air, with 1 filter skin.
    Leak Jet: Stock 70
    Pilot Jet: Stock 45
    Main Jet: 168
    Needle: Stock NCVS
    Needle Clip Position: 4th from top
    Fuel Screw Type: Adjustable, Don't recall brand
    Fuel Screw Setting: 2 turns out.
    Tie-Wrap mod: Removed (it was sticking)
    Exhaust Type: Procircuit T4 with noise baffle
    Header: Stock
    Pink Wire Modified: Yes
  • AngrySlinky
    Posts: 26
    Joined: Tue Oct 11, 2011 2:48 pm

    by AngrySlinky » Fri Oct 14, 2011 5:12 pm

    Model:2006 crf450r
    Settings for what altitude:1000-3000
    Main jet size: 180
    Needle used: Stock
    clip location: 4th
    Airbox mods:Cut open
    Air Filter changes:Back fire screen removed, Twin Air Power Flow Air Filter
    Any other related changes: Full AP Mod, Full Bills Pipe Exhaust
    Mixture Screw Turns: 2-1/4 around 1000ft; 1 turn around 3000ft
  • User avatar
    230@#)
    Posts: 57
    Joined: Thu Apr 26, 2007 7:54 pm

    by 230@#) » Tue Nov 08, 2011 7:27 pm

    Model: 2003 450R
    Settings for what altitude: 300 m
    Main jet size: 175
    Needle used: Stock
    clip location: 6 th spot
    pilot: 45
    Airbox mods: stock
    Air Filter changes: Twin air Air filter
    Any other related changes: White Bros Full exhaust Carbon Fiber canister
    12-1 compression piston
    Outlaw racing quichshot
    I had a boyesen power wing but it made it felt way worse. I dont know what do you guys think about the power wing does jetting need to be adjusted to get the claimed benefits.

    Need help for jetting during the winter months for riding at the Indoor track. Temp is around 5C and -10C or so when riding. It feels like its lacking on 0-1/4 throttle mostly I am thinking a 48 pilot a 178 main. and Maybe raise the needle to the top I dont know any advice would be greatly appreciated
  • saefabri
    Posts: 35
    Joined: Sat Feb 02, 2013 2:18 am

    by saefabri » Mon Mar 18, 2013 8:57 am

    Model: 450X, 2010
    Settings for what altitude: 1100 ft
    Main jet size: 170
    Needle used: JD red
    clip location: 4th
    Airbox mods: as per JD instructions. Left and right cuts.
    Air Filter changes: K&N air filter
    Any other related changes: Exhaust system from Two Brothers.
  • OhioCRF
    Posts: 2
    Joined: Sat Mar 16, 2013 12:44 pm

    by OhioCRF » Mon Apr 01, 2013 4:28 pm

    2008 450x
    Jd jet kit
    Main 165
    Slow stock
    Needle jd red 4th clip
    Air box mods per crfs only sides cut and top snorkel removed
    Fmf power bomb header, lexx mx slip on muff
    Twinair power flow filter

    Will be removing stock screen and changing main to 170
    Big improvement over stock pulls hard through entire rpm
  • FourstrokeFelix
    Posts: 2
    Joined: Fri Apr 19, 2013 7:15 pm

    by FourstrokeFelix » Fri Apr 19, 2013 7:26 pm

    Hey! Im new to this forum and I just got a 2005 crf250R after trading my cr250r! I love this bike but Ive got to get it jetted which im not really looking forward too! The bike is decently hard to start but once it gets started doesnt idle consistently. It tends to bog down and die and the acceleration bogs ALOT. I simply couldnt ride like it was because it was too lean and decided to get a JD kit to straighten it out. The bike has a full PC Ti4 exhaust with titanium header, Hotcams stage 2, and a Boyesen quick shot and it was never jetted. Im guessing this has a lot to do with its lean condition right now. when it was warm it would run a bit with some difficulty but now that its a bit colder this week, it just does not stay running, bogs down while riding. Tomorow I'm going to install the new jets and needles but before I do anything id like to know if anyone has a recommended jets and needles setup for the altitude I'm at around 1200 ft above sea level at cumming GA! any ideas anyone? thanks! also my email is felucosalazar@hotmail.com :-k
  • boosted97cobra
    Posts: 3
    Joined: Tue May 28, 2013 5:54 am

    by boosted97cobra » Fri Jun 14, 2013 10:16 am

    I am using heihin jets to jet my bike i do not have jd jet kit. i was wondering if a keihin jet is the same as a jd. Meaning is a 170 main from Keihin the same as a 170 main from jd.
  • rayg450
    Posts: 1
    Joined: Sun Aug 05, 2018 6:34 pm

    Re: Jetting database for Honda CRF's

    by rayg450 » Sun Aug 05, 2018 6:46 pm

    i crushed my exhaust flipping over so i cut the stock echaust off and i had an old slip on from a street bike laying around so i welded a peice of exhaust pipe to go from standard size to 1-7/8 for this akrapovic slip on to fit. im not wondering what roughly the jetting should be on it. my bike is a 2003 crf450r and im at 410m elevation, thanks in advance
  • Leardriver
    Posts: 462
    Joined: Wed May 05, 2010 10:33 am

    Re: Jetting database for Honda CRF's

    by Leardriver » Mon Aug 06, 2018 8:58 am

    That's the kind of garage engineering that I like!
    The jetting should be a 165 main, unless you are riding in 90 degree temps, where at your altitude a 162 would be perfect. Either one will run so good that you wouldn't be able to tell. A 45 pilot and about 1 7/8 turns out on the fuel screw for every CRF 450.

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