Topic: Advice needed - Changing jets in a CB400F

[obrut]

Hi All,

I've ordered some bigger main jets for my bike to suit the aftermarket muffler and velocity stacks.

Can I change the jets without removing the carbs from the bike - or is it easier to pull the carbs first?

Cheers, Ryan

Ps. Can anyone direct me to a guide for changing jets and/or moving the clips?

[fmctm1sw]

I would say maybe but not very easily.  If you had a screwdriver small enough to get to the screws and a way to hold the jets and accompanying jet holders in place, you could do it.

[Gorms]

If your 400 carbs are similar to my 550 carbs, you can change the jets and the needles without removing the carbs.  I got my float bowls off with he carbs on the bike and unscrewed the main jets/emulsion tubes and changed the jets.  I also changed the needle setting by removing the top caps of the carbs, unscrewing the slide arms from the throttle rod and the tops of the slides, pulled out the needle with pliers, changes the clip, and put them back together.  Once again, not sure how similar 400 carbs are.

[HondanutRider]

I don't think the CB350/400F carbs are the same design as described previously for the CB500/550F.  The main jets on these models are not screwed-in, but rather are held in place with a holder under the float bowl.  The small o-rings that are around the base of the jets to seal them, often are swollen and make the jets very stubborn to remove, even if they just "pull" out.

You would be ill-advised to try replacing the jets without removing the carburetors, which can be done fairly easily without removing them from "the rack".