SOHC.co.uk Forums > CB500/550

Fuel Height

(1/8) > >>

Steris:
Morning all.
I am having slow running problems, bike runs fine above about 3000 rpm, but wont tick over and has no power when pulling away. The plugs are all sooted up. When i set the float height to 22mm
the fuel over flows on all 4 carbs. Needles are on the third groove down. I have got the carbs off and stripped and ultrasonically cleaned them and all the jet etc.  I have set each carb up on the bench with a sight tube so i can see the fuel level. At 26 mm float height the fuel level is 10 mm below the float bowl lip, and when drained into a beaker there is 50 ml in the float chamber. I seem to remember reading that this is right, can anyone shed any more light on this for me please.. Its driving me mad  ::)

Many thanks Andrew

Nurse Julie:
Did you set the float heights correct Andrew. I'm sure you did but I'm just checking 😊
http://www.sohc.co.uk/index.php/topic,23233.0.html

Steris:
Hello Julie

Yep, I have set them just like you describe, this time I've set them individually ie off the bracket. I'm wondering if the springs in the needles have become weak, hence the need to make the float height greater, from 22 to 25/26. This would allow the float to exert slightly more pressure and seal the fuel flow.  I have know read that the fuel should be 3-4mm from the top of the float bowl so i will adjust again tonight and see what i get.

Thanks for your reply :)

Bryanj:
I have seen needle with "sticky" pins, i cleane them in acetone and it improved them

K2-K6:
Clean / polish the taper seat of the inlet by using a small dowel sharpened like a pencil with something like t-cut to make sure it promotes a good seal. You can either spin it with you hands or in a drill slowly to improve any surface imperfections. 

It usually helps the valve shut off easily with just the minimum of pressure.

If the moving  valve tips aren't rubber (brass) you can also polish these the same. 

Navigation

[0] Message Index

[#] Next page