03 450f carb apart (grayracer help! heh)

5 replies to this topic
  • soulsedg3

Posted October 11, 2014 - 12:59 PM


So in a previous thread (under silencer packing) i showed my carb overflow leaking.   I pulled the carb off and discovered 2 things right off.   


1st - the gasket for float bowl was broken (not by me, i took it apart very very slowly.  but it wasn't the source of leak, it was leaking, but the overflow was also leaking cause i wiped the carb down, and within 10 seconds the overflow at bottom of carb had a drop, and sides of carb seemed dry)


2nd - the little fuel screw that is red, going into the carb, that was turned all the way in.   if you turned it out a little bit, it was very very loose.  It was almost like the spring in there wasn't keeping pressure on it, which i assume is why it was turned all the way in.  


I pulled the float off, and took the float needle out, and looked at the rubber stop on it, it doesn't seem to bad to the untrained eye of myself.    But the copper piece of whatever that it stops in, was questionable, i dont know what i'm looking at here so i took pics for you all.    I'm hoping to get greyracer and a few others of you to make suggestions.    The bike popped when letting off,  but ran up thru the power quite good, no stutters, etc.


Should i attempt cleaning, doing something with this carb, or should i just send it to zipty racing, to have it modded, cleaned, fixed, etc. ?    I'm very novice when it comes to carbs.   i know some of the parts names.  etc,  main jet, blah blah.  But i do not know how they function really, and stuff like that in depth.    And i'm not quite sure how to set the float lvl.    In the old bikes i had, you just bent a little piece and it adjusted the floats lol.


Anyways here are some pics. let me know what you all think!




Float Bowl.....







Float Bowl Gasket






Bottom of carb.....







Main jet Size?



Edited by soulsedg3, October 11, 2014 - 01:05 PM.

  • soulsedg3

Posted October 11, 2014 - 01:02 PM


more Pics...









Float assembly.....







Fuel screw





Float needle





and the float seat.  



Edited by soulsedg3, October 11, 2014 - 01:04 PM.

  • William1

Posted October 12, 2014 - 12:33 PM


Main is a 165 ('S' is for 'Standard' or 'Stock', OEM)

Yes, get a new float bowl gasket. That can seep from just vibrations.

Fuel screw should have a spring then a washer and then an oring on it. I am not a fan of alloy fuel screws. Notice how the tip on that is tapered. OEM (and most aftermarket brass or stainless) do not have that taper.

Float needle and seat look fine. Seat has a oring on it that can dry out and fail. The seat has to be removed to check it. Usually requires a small slide hammer and trained mechainc to remove it damage free.

You may want to throw in a new pilot jet so that layer of fuel varnish s not an issue.

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  • soulsedg3

Posted October 12, 2014 - 05:50 PM


Ahhh awesome william! Thank you very much! I live in a small town and dont know of anyone that does carb work.

The fuel screw i cant turn out more then 1/4 turn before it comes loose and could easily spin on its own just grom vibrations. I didnt see an oring or washer on the fuel screw. Just the spring stuck down inside.

I think judging by what you said...it may be cheaper for me to send it to zipty racing to mod and rebuild.

Edited by soulsedg3, October 12, 2014 - 05:51 PM.

  • grayracer513

Posted October 13, 2014 - 07:00 AM


The needle seat on the '03 and later carb isn't serviceable/removable.  The float needle looks worn.  The entire carb looks like somebody's been digging in it with pliers and a screwdriver for a while.  Clean up the needle seat with the end of a nylon bore brush. Once you reassemble the float, connect it to the gas line and turn the gas on while holding the float up gently.  It should seal and hold without having to compress the little spring pin in the needle.


Yamaha will sell only individual gaskets.  Go to a Honda shop and get a rebuild kit for an '03 CRF450. 

  • soulsedg3

Posted October 13, 2014 - 07:36 AM


Grayracer. You are a saint man! Thank you! Going to try that now

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