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Thread: crf 50 big bore question..

  1. #1
    Join Date
    Jun 2004
    Location
    chicago il
    Posts
    564

    crf 50 big bore question..

    aint exactly a trx90 or a quad but this is the best place i could think to ask this..I put my buddies 88cc big bore kit in his 50 today and got it runnin good, it idles fine but when I twist the throttle it'll die, if I feather the throttle it'll rev up fine and if the rpms are above idle it go fine but I can't figure out why it'll die when I hit the throttle at idle? I've cleaned the carb, messed with all the adjustments on the carb. anybody think it could be the timing is still off a tooth?? or any ideas on how to fix it?

  2. #2
    Join Date
    Mar 2003
    Location
    Hebron, CT
    Posts
    50
    Sounds like you need to go up in size on your pilot jet. If you are running a UNI style filter the added air flow(or cold air!!) will call for a bigger pilot. Sometimes a needle jet adjustment will handle it.
    Anthony Roncone #45
    2004 NEATV 50cc Modified MX Champ
    2003 NEATV 50cc Modified MX 2nd
    2005 Ride --> Honda TRX125 by Robbs Racing Engines

  3. #3
    Join Date
    Jun 2004
    Location
    chicago il
    Posts
    564
    forgot to add that this is an R-stage kit so it came with a new carb and all, arent those kits pre-jetted? could it be that its only 35 degrees out and its not jetted for that cold of weather? but in my shop its 65 degrees so...

  4. #4
    Join Date
    Feb 2004
    Posts
    14
    I have had to rejet everytime with aftermarket carbs! xr50s, ct70s, klx110s, etc. --> all the same type of 4-stroke motors

    cold air does it everytime when your not running and air box

  5. #5
    Join Date
    Feb 2006
    Location
    nw ohio
    Posts
    26

    check out this site

    www.fiddylife.com

    go to the tech forum and address the question to Fab...........

  6. #6
    Join Date
    Jan 2004
    Location
    wolcott ct
    Posts
    550
    hey mr. roncone check your pms
    Prescott racing 911-06 R w/HRC Houser+2s LSR axel & GT Thunder(o5). Jay30+A,6th-OPEN-A,5th Ty PROD90,8th Dyl 50lim,10th NEATV-MX sponcers,RER--MAIER--NAC'S-ELKA-SCOTT-SIGN TECH-EAST COAST CUSTOMS

  7. #7
    Join Date
    Dec 2003
    Location
    NEW HAMPSHIRE
    Posts
    350
    Mr. Roncone has given up quad racing and has switched over to dirtbikes. Im not so sure you will find him here anymore.
    WWW.ROBBSRACINGENGINES.COM

    Robbs Racing Engines 2003 NEATV-MX Engine Builder of the Year.

    #7 Robbie Leonard
    2002 50cc stock Class Champion NEATV-MX
    2003 50cc Mod. Class Champion/70 mod. 2nd. place NEATV-MX
    2004 70cc Mod. Class Champion/90 Prod. 2nd. place NEATV-MX
    2005 GNC-MX 90 Prod. Jr 3rd & 70 Mod.2nd.
    2006 NEATV-MX 90 Mod. & 90 Jr. Champion

    #7X Devin Leonard
    2006 NEATV-MX 50 Limited 3rd & 70 Prod. 3rd

  8. #8
    Join Date
    Jan 2004
    Location
    wolcott ct
    Posts
    550
    hey rob, i know he sold out i was over his house this spring w/ the kids riding but i lost his phone # if you still have it could you pm it to me? i pm'd him on here but like u said he must not come on anymore. thanx and buy the way robbie is smokin this year. wish i could watch him more in my sons class (90 jr) but i ruptured my akilies tendon at twister and we'll be missin most of the season ( maybe unadilla) good luck to both the kids. Jay
    Prescott racing 911-06 R w/HRC Houser+2s LSR axel & GT Thunder(o5). Jay30+A,6th-OPEN-A,5th Ty PROD90,8th Dyl 50lim,10th NEATV-MX sponcers,RER--MAIER--NAC'S-ELKA-SCOTT-SIGN TECH-EAST COAST CUSTOMS

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