2003 450 carb problems

9 replies to this topic
  • XR250_RIDER_14

Posted April 14, 2007 - 05:10 PM


Hey just wondering anyone with the 2003 have these problems; When I go over some jumps my 03 dies when I land. It stalls and bogs VERY easily since it was rebuilt and regeared(15-49). I geared it up a lot. Should it be stalling this bad? What is the cure for these things. I am asking this mostly to grayracer since I think he said he had an 03 geared 15-49.

Is there any bolt on carb mods I could use. I'm not good at working on carbs though so the least trouble would be nice.

  • Radbuster

Posted April 15, 2007 - 06:16 AM



Mine was bogging very badly on landings untill I installed a Boyesen accelerator pump cover.

Jetting is stock 42PJ, 165main, except for a NCVP #4 needle that is one step richer on the diameter (0 - 1/8 throttle opening). NCVQ #4 is stock.

Timing of the accelerator pump is important, and tuning it like it says in the manual works well. On the '03s the leak jet regrettably can't be changed.

The accelerator pump membrane gets soft with time so I change mine about every 3 months.

I used to have a lot of bogging on landings and flameouts coming out of corners but now it works perfectly almost always, has great response and the plug has a nice color.

Also, on these "older" bikes the pipe might have been taken off and on a couple of times. The 3mm soft gasket sitting between the cylinder and pipe is probably crushed and causing a small leak. This leak is a likely culprit that produces strange jetting issues.


  • dwnlowx

Posted April 15, 2007 - 08:08 AM


my bike is an 04 sometimes when im jumping alot over and over my bike will die and will become very hard to start unless i gas the hell out of it but it will still die unless i stay on the throttle it must be fludding or something

  • Ga426owner

Posted April 15, 2007 - 09:30 AM


I do not have this issue on my 03. Sounds like the float is out of whack -
Set the float height or just remove the carb and send to ZipTy for a complete rebuild/tuning.

  • grayracer513

Posted April 15, 2007 - 11:04 AM


I don't have a problem with this either, and it does sound like a float level problem.

I have seen posts concerning this particular complaint in which the problem was solved by removing the one way valve from the tank vent. Since I still have mine in place, that would mean that theirs was defective, and not that all of them are too restrictive. Worth a try.

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  • XR250_RIDER_14

Posted April 16, 2007 - 05:27 PM


How much money does it cost to send it to Zip tye and be rebuilt? I dont want to spend that much money. I would like a estimate or a guess on what it would be. What would be the advantages?

  • XR250_RIDER_14

Posted April 16, 2007 - 06:38 PM


Answer would be nice please. And advantages

  • grayracer513

Posted April 16, 2007 - 09:50 PM


It wouldn't occur to you to search, I guess?


  • Ga426owner

Posted April 17, 2007 - 06:30 AM


Answer would be nice please. And advantages

for the long detailed answer search + you will get real feedback from those who have done it...for the short answer 100.00 and a carb that works properly and a bike that has better throttle response and power....and no bog period....that is all :thumbsup:

  • XR250_RIDER_14

Posted April 17, 2007 - 03:05 PM


Wow, I expected it to be more than 100.

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