300ex Carb Question

[300exwoodsracer]

Been rejetting my 300ex... put a 130 main in, adjusted the needle on the clip, and when putting my main in, this is my question... In the pic, you can see where the main jet screws into what seems another jet - which surrounds the needle... well u can see a nut on this which allows it to be screwed farther in or out... what effect does this have exactly?? Thanks

[300exwoodsracer]

:D ??

[Jay300ex]

I'm not positive but it may be just some sort of another seat. Since its not like an adjustment screw and turning it in and out doesn't change the mixture or anything.

[300exwoodsracer]

so you guys think no matter how far in or out that "jet" is its not going to make any difference?? just seemed to me there would be a purpose to that nut.. or is it just suppose to be screwed all the way in? cuz thats how it was when i opened the carb

[hondafox440]

Thats just there to hold the jet in place. All carbs have them. make sure it is tight, but not overtightened as to trip the carb body or head of the seat, or even worse, snap it.

[300exazzkikr]

Originally posted by hondafox440
Thats just there to hold the jet in place. All carbs have them. make sure it is tight, but not overtightened as to trip the carb body or head of the seat, or even worse, snap it.

when i had a mini bike i snapped it off on the carb..:(

[hondafox440]

Haha, smart. How did you keep the main jet in place?

[300exwoodsracer]

just to make sure... see the main reason i ask is because the top of the "jet" isnt seated all the way down to the nut... theres about 2 lines of threads... its tight because the nut is tight onto the carb... but should it be tightightened all the way into the nut?... didnt make that question clear earlier

[hondafox440]

On all carbs I have touched, it was seated perfectly, so you may want to try again to get it seated, or make sure you have the correct jet for your carb.