450x jetting dramas
  • slicnic
    Posts: 44
    Joined: Thu Sep 16, 2010 2:56 am

    450x jetting dramas

    by slicnic » Fri Feb 21, 2020 12:47 am

    so ive been noticing for a while that my jetting was not at 100% where it should be , kind of spluttering when cruising along at a constant speed. my diagnosis was the floating valve plate and seal as i have changed it once before a long time ago when noticing similar symptoms and that had solved the problem. and also another thing i had read which i have changed before in past with good results was a new needle. ( was running a jd red needle ,165 main and 45 pilot ) for a long time this has been working perfect, so i changed the floating plate and seal ( installed correctly) and a new needle but only the stock honda one this time and also new emulsion tube . cant find the jd needle on its own without buying the whole kit just for the needle. so after swapping out these parts i cant for the life of me get the bike to run even moderately fine , it only runs with choke on , pops and backfires , dies soon as the choke is off. have since pulled the carb completely out cleaned every posible passage ,and event put old needle back in with slightly better results but still not enough to run more than half a minute. any help please cos im about to let loose on it with a big hammer!
  • Back2-2
    Posts: 1148
    Joined: Tue Jan 04, 2011 3:31 pm

    Re: 450x jetting dramas

    by Back2-2 » Fri Feb 21, 2020 6:21 am

    It sounds like you are proficient are working on the carburetor so please do not take insult to this recommendation. I suspect that even though you said all is clean that the pilot jet may still have a slight restriction from debris. The symptoms you described are usually the pilot jet.
    Other items to inspect:
    Air fuel screw o-ring and orientation.
    Air leaks on the intake boot and seal to the carb.
    Rubber seal at the throttle cable holder on the carb top.
    Throttle slide for wear - Doubt this one but worth a check it.
    Air filter condition and seal.

    Hope this helps a little a most the things that can give you symptoms you described.
    Neil
    Black Hills of SD
    Life without Motorcycles would just be boring, really boring
    Honda 450X. Yamaha Tracer GT900. HD Fat Boy. Triumph Bonneville. Yamaha Majesty 400. Yamaha Grizzly. Yamaha Wolverine. Yamaha TW200
  • slicnic
    Posts: 44
    Joined: Thu Sep 16, 2010 2:56 am

    Re: 450x jetting dramas

    by slicnic » Fri Feb 21, 2020 2:07 pm

    thanks its just annoying because it was running not too bad before but now cant get it to run at all good. i was thinking the pilot circuit too, i blew air through it , how else can i be sure that its clear? the fuel screw was all good clear and the little oring in good shape. the bike is old but things wouldnt just happen all of a sudden like this ?
  • Aussiecrf230
    Posts: 1962
    Joined: Fri Jan 06, 2006 11:11 pm

    Re: 450x jetting dramas

    by Aussiecrf230 » Fri Feb 21, 2020 10:38 pm

    Hi Slicnic,
    The idle jet has both the vertical and horizontal passages and it doesn't take much or too long to block or restrict them.
    They can get to point where they work then you jump back on and won't run.
    Ray
    Australia

    CRF230F 2004
    C30F Power Up needle
    Mains 132
    Idle 45
    2 turns out
    Baffle out, Screens In

    It starts,it runs,it gets to where all CRFs can get to without the valve or valve plate dramas
  • Leardriver
    Posts: 462
    Joined: Wed May 05, 2010 10:33 am

    Re: 450x jetting dramas

    by Leardriver » Sat Feb 22, 2020 9:25 am

    A new 45 pilot and a 165 main at sea level will run just fine. What elevation are you at? It won't matter for smooth running, you can be 5 main jet sizes off and a 450 will run.

    The stock needle works great. As tinkerers, everyone thinks that they found a better set up than the Honda engineers who do this all day every day, and have a virtually unlimited budget. As long as we consider that they have emission constraints rather than perfect drivability goals, we can trust the original setup to be very close.
  • JED50x
    Posts: 4
    Joined: Wed Jan 22, 2020 6:01 pm

    Re: 450x jetting dramas

    by JED50x » Sun Mar 01, 2020 8:29 am

    It sounds like you are proficient are working on the carburetor so please do not take insult to this recommendation. I suspect that even though you said all is clean that the pilot jet may still have a slight restriction from debris. The symptoms you described are usually the pilot jet.
    Other items to inspect:
    Air fuel screw o-ring and orientation.
    Air leaks on the intake boot and seal to the carb.
    Rubber seal at the throttle cable holder on the carb top.
    Throttle slide for wear - Doubt this one but worth a check it.
    Air filter condition and seal.

    Hope this helps a little a most the things that can give you symptoms you described.
    I could use some help, too. I just finished jetting my carb (also 450x) and am having a heck of a time trying to get the intake boot and seal to fit properly again on the carb. There is just so little room in there to work (and it is hard to see). Does anybody have any tips/tricks to make this any easier?

    Thanks!

    Jed
  • Back2-2
    Posts: 1148
    Joined: Tue Jan 04, 2011 3:31 pm

    Re: 450x jetting dramas

    by Back2-2 » Sun Mar 01, 2020 9:48 am

    Hello. First it is important to have the rubber warm so that it is flexible. I have used a cotter key extractor tool many times on bikes to hook under the rubber boot with a slight trace of lubricant and "roll" the boot onto the manifold or carb throat. Using caution to not stress the rubber and to not let the point of the tool to cut or poke the rubber. But the shape and curve real works good for this task. After it is on I always use a flashlight and mirror to inspect that is is indeed on and positioned correctly.
    That's what I do and on some bikes it can be a challenge others easy. Patience and persistence.
    Neil
    Black Hills of SD
    Life without Motorcycles would just be boring, really boring
    Honda 450X. Yamaha Tracer GT900. HD Fat Boy. Triumph Bonneville. Yamaha Majesty 400. Yamaha Grizzly. Yamaha Wolverine. Yamaha TW200
  • JED50x
    Posts: 4
    Joined: Wed Jan 22, 2020 6:01 pm

    Re: 450x jetting dramas

    by JED50x » Sun Mar 01, 2020 9:20 pm

    Hello. First it is important to have the rubber warm so that it is flexible. I have used a cotter key extractor tool many times on bikes to hook under the rubber boot with a slight trace of lubricant and "roll" the boot onto the manifold or carb throat.
    Thanks. I have one and I will give that a try.

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