tecate1987 0 Posted September 2, 2022 (edited) how can I determine if a carb is from a 300ex or a 400ex? I just got a 2001 400ex and the main jet is only 127. stock 300ex is 122 so I was wondering if its only a 300ex carb. Edited September 2, 2022 by tecate1987 Share this post Link to post Share on other sites
shadetree 5,970 Posted September 2, 2022 38 minutes ago, tecate1987 said: how can I determine if a carb is from a 300ex or a 400ex? I just got a 400ex and the main jet is only 127. stock 300ex is 122 so I was wondering if its only a 300ex carb. side of carb has a number stamped on it, go to partzilla, find your make/model/yr, look below the carb name, it should have the carb part number showing you the correct carb for your atv. next time, please include the year of your atv, this makes it easier for us to help you ! :-). 2 Share this post Link to post Share on other sites
tecate1987 0 Posted September 2, 2022 thx but I have a carb I am trying to determine if its from a 300ex or a 400ex carb. Share this post Link to post Share on other sites
AKATV 840 Posted September 2, 2022 As per the service manual (they are free here on the forum) The 2001 400EX carburetor casting ID should be QB10A with a 148 main jet The 2001 300EX carburetor casting ID should be QB02B with a 122 standard main jet or a 122 high altitude main jet Share this post Link to post Share on other sites
tecate1987 0 Posted September 2, 2022 ok thx mine shows QB 10A again however my main is 126 or 127 dont remember at this point. Im gonna get a larger jet for it. thx Share this post Link to post Share on other sites
AKATV 840 Posted September 2, 2022 (edited) link to the manual if you need it- https://drive.google.com/drive/folders/1_4YEHFDi8Yvn3tFKuKhxxspOvgKDl9xa Carburetor information is on 2nd page of fuel system section, page 5-2 Edited September 2, 2022 by AKATV Share this post Link to post Share on other sites
SlammedRanger 1,560 Posted September 2, 2022 Post a picture. I will tell you which one its from. Welcome to the forums! Sounds to me like it has a dyno jet kit. Those jets go on a totally different scale. 1 Share this post Link to post Share on other sites
tecate1987 0 Posted September 3, 2022 carb pics, so dyno jet kits go by different numbers? Share this post Link to post Share on other sites
SlammedRanger 1,560 Posted September 3, 2022 That is without a doubt a 400ex carb. The dyno jets go on a different scale completely. So yes number would be way crazy. They are also round with a flat head slot in them. Where the oem jets are hex jets. 1 Share this post Link to post Share on other sites
