Carbs

**Car Dodger** · 23rd October 2003, 11:27

Hey guys

Does anyone know how to set the floats on a 79 model CB400
twin carb?
I can get the floats off but thats it.

**jrandom** · 23rd October 2003, 11:48

A quick google turns this up. Some of the other articles on that site seem to indicate that you might have a losing battle ahead of you

**Car Dodger** · 23rd October 2003, 11:54

Originally posted by jrandom
A quick google turns this up. Some of the other articles on that site seem to indicate that you might have a losing battle ahead of you

Sorry didnt understand that dude.

**jrandom** · 23rd October 2003, 11:57

Originally posted by Car Dodger
Sorry didnt understand that dude.

Sorry, did you click on the link? I was referring to the fact that there were a number of people who seemed to dislike fiddling with the carbs on that model line of CB400s.

Best of luck, though

**Car Dodger** · 23rd October 2003, 12:01

Originally posted by jrandom
Sorry, did you click on the link? I was referring to the fact that there were a number of people who seemed to dislike fiddling with the carbs on that model line of CB400s.

Best of luck, though

Ohhhh, I got it now. sorry I'm new to the Kiwibiker club.

**merv** · 23rd October 2003, 12:07

Originally posted by Car Dodger
Hey guys

Does anyone know how to set the floats on a 79 model CB400
twin carb?
I can get the floats off but thats it.

How do those floats operate the needle valve? In many carbs if there is no easy adjustment you end up just having to bend the small tab thing that pushes on to the bottom of the needle to get the floats set at the correct measurement. The real question is though what makes you think they need setting?

**Car Dodger** · 23rd October 2003, 12:15

Originally posted by merv
How do those floats operate the needle valve? In many carbs if there is no easy adjustment you end up just having to bend the small tab thing that pushes on to the bottom of the needle to get the floats set at the correct measurement. The real question is though what makes you think they need setting?

Im not 100% sure, Its pissing out gas from the right carb overflow. I have cheaked the overflow valve and bowl & all is good, I am just guessing that it may be getting to much gas.

**merv** · 23rd October 2003, 12:25

Originally posted by Car Dodger
Im not 100% sure, Its pissing out gas from the right carb overflow. I have cheaked the overflow valve and bowl & all is good, I am just guessing that it may be getting to much gas.

If its overflowing then chances are it is leaking past the needle valve and I'd say you'll need to replace it. If the motor was just running rich then maybe the float level was too high.

**Car Dodger** · 23rd October 2003, 12:54

Originally posted by merv
If its overflowing then chances are it is leaking past the needle valve and I'd say you'll need to replace it. If the motor was just running rich then maybe the float level was too high.

Good Idea, I have a spare carb set up, is it just a matter of swaping the bowls?

**gpercivl** · 23rd October 2003, 13:24

Seeing as you have two carbs and one is OK, then you could try placing a clear plastic tube on the drain pipe of the carb then hold it up vertically. Now loosen off the drain screw and the fuel level will appear in the plastic tube. Now check the flooding carb, if it rises above the carb bowl then either the needle valve is jammed open, needs replacing, or needs resetting (which requires carefully bending the metal tab as described in a previous note). If you do this you'll then need to recheck the fuel level height.

Find yourself almost any motorcycle repair manual and this technique will be described.

**Car Dodger** · 23rd October 2003, 13:42

Originally posted by gpercivl
Seeing as you have two carbs and one is OK, then you could try placing a clear plastic tube on the drain pipe of the carb then hold it up vertically. Now loosen off the drain screw and the fuel level will appear in the plastic tube. Now check the flooding carb, if it rises above the carb bowl then either the needle valve is jammed open, needs replacing, or needs resetting (which requires carefully bending the metal tab as described in a previous note). If you do this you'll then need to recheck the fuel level height.

Find yourself almost any motorcycle repair manual and this technique will be described.

Cheers Mate

**gpercivl** · 23rd October 2003, 14:16

1980 and a CB400N from Forbes and Davies was my first brand new bike....that brings back memories...highsided it in a left hand corner near Netherton in the rain about 1 month later....ah yes, those were the days!

**Car Dodger** · 23rd October 2003, 14:43

Originally posted by gpercivl
1980 and a CB400N from Forbes and Davies was my first brand new bike....that brings back memories...highsided it in a left hand corner near Netherton in the rain about 1 month later....ah yes, those were the days!

My first bike was a 80s model GL100 great fun until I put it into a medium barrier one rainy Friday night.

**merv** · 23rd October 2003, 18:39

Originally posted by Car Dodger
Good Idea, I have a spare carb set up, is it just a matter of swaping the bowls?

Usually the needle just drops out when you remove the float mounting and thats normally fastened to the carb body not the bowl.

You could check if the spare carb doesn't leak when you connect it to a fuel line and if its OK probably best you just change the carb. Reason being if a needle valve leaks it could be the needle or it could be the seat thats buggered.

**Car Dodger** · 24th October 2003, 10:22

Originally posted by merv
Usually the needle just drops out when you remove the float mounting and thats normally fastened to the carb body not the bowl.

You could check if the spare carb doesn't leak when you connect it to a fuel line and if its OK probably best you just change the carb. Reason being if a needle valve leaks it could be the needle or it could be the seat thats buggered.

Its cool man I swaped the float assembly last night, and all is good. still running a little rough though.
PS ( Seats brand new!!)