WR400 Needle and seat

6 replies to this topic
  • acarter92

Posted May 14, 2009 - 05:09 PM


Hi, I need a needle and seat for a 99' wr400 and can't find one anywhere other than at the local dealer for $60 which seams pretty steap. I looked on countless aftermarket sites and distributers with no luck. Does anybody know where I could find one? Also, if the needle is bad would it make the bike run bad (bogging when I get on the gas quick) or just leak out the overflow.


  • acarter92

Posted May 15, 2009 - 03:17 PM



  • William1

Posted May 15, 2009 - 03:26 PM


Cost for a needle and seat is about $55.

A bad needle/seat can cause fuel to come out the overflow, it could cause the bike to be so rich it bogs though it would also run poorly across teh rev range. A float set too high can do the same thing. Check the height first.
A bog is usually a issue with the AP circuit. If it has always been there, it is probably out of adjustment. If it recently happened, it is eaither a clog in the circuit or a bad diaphragm.

If you are convinved the needle valve is not fully closing, it is often not the valve rather the oring between teh seat and carb body has gone bad. A real good dealer has just these orings. Very few fiches show them so finding them is not easy however if you have an oring supplier nearby, they can easily hook you up.

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  • Birdy426

Posted May 15, 2009 - 08:18 PM


Sudco sells the individual components...needle, seat, scren, o-ring, etc. The total is a lot less than the yamaha dealer. They do have a 25 dollar minimum order for non-dealers, so if you need other stuff, you might check their on line catalog. Otherwise, you might want to get the Sudco part numbers that you want and have your dealer order them...

  • vfr661

Posted May 16, 2009 - 03:28 PM


I have an 00 WR400 that had the same problem with the needle valve set. After I took the needle valve set out of the carb, I diagnosed the problem to be the o-ring only. I took the needle valve set to a local motorcycle shop so they can find the exact o-ring. The charged me cost me 25 cents for the o-ring. Most motorcycle repair shops carry o-ring sets that contains various sizes so try that route.

Another option is get the whole 0-ring set from Harbor Freight for about $12.

  • acarter92

Posted May 17, 2009 - 01:48 PM


Thanks guys, I really do appreciate the replies. I did check my float hight and if I did it right then it was good. The bogging down starter about the same time it started to leak out the overflow which is why I though it was the needle and seat making it bog. I'm going to order a new o-ring from sudco and just order some other little things that I need for my streetbike to get the minimum order amount. I don't think that I'll need a new needle because it looked fine when I checked it out ( I never looked at the o-ring) I'll let ya'll know how it works out.

Thanks again,

  • Birdy426

Posted May 17, 2009 - 03:08 PM


Another option is get the whole 0-ring set from Harbor Freight for about $12.

The Harbor Freight kit doesn't have the right size. Maybe Motion Industries.


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