Date: 25-02-24  Time: 17:35 pm

Author Topic: Rebuilt carbs twice, still pouring fuel from float bowls  (Read 509 times)


  • Cager in Training
  • Posts: 2
    • Main bike:
      FZS600 98-99
    • View Profile
Rebuilt carbs twice, still pouring fuel from float bowls
« on: 20 November 2023, 06:09:42 pm »

Basically as the title says, bike has been out of action for a couple of years and it developed a fuel leak on one carb. Found a blockage in no.3 carb and I decided to strip and rebuild the carbs with a rebuild kit about a year ago, and one carb leaking turned into all four. Also had to replace one of the manifold rubbers on the airbox as it had deformed. Came back to it a week ago and stripped and rebuilt again, checked all float bowl gaskets etc were sealed properly and put the carbs back in again. Same issue again.

I feel like im banging my head against a brick wall as nothing I try will stop the issue, and i'm not really wanting to spend money getting them professionally rebuilt as the bike in it's current state is worth around what it would cost to get done.

Any tips as to what I may be missing? I'd never done this before, so want to make sure I touch all bases before I make a serious decision on where to go next.



  • GP Hero
  • ******
  • Posts: 5,299
  • Never ride faster than your guardian angel can fly
    • Main bike:
      FZS600 02-03
    • - FZS1000 05-06, Serow 2000
    • View Profile
Re: Rebuilt carbs twice, still pouring fuel from float bowls
« Reply #1 on: 21 November 2023, 11:39:10 pm »
Three things that usually cause leaks :
1. Float Valve O-Ring, Replace them, don't go wasting money on  rebuild kits just buy the O-Rings( Replace the Main jet O- Ring as the same time)
2. Fuel Line O-rings between the carbs Replace them requires separation of the carb bodies
3. Flattened Float Gasket/Seal, replace them and use plain grease when refitting, seals and excess washes off with petrol.  Suzuki ones can be half the price of Yamaha ones. All the Mikuni BSR Carbs use the same

A word of advice Do not use use silicon sealers or gasket makers anywhere near a carburetor.

What did you do/replace in the rebuild?