1978 CB750FZ DOHC Carb number 4 overflow

[The Orcadian]

Just cleaned, ultrasonic & rebuilt carbs on my 1979 CB750FZ DOHC. Carb 4 ONLY overflows through rubber ovderflow pipe when I open tank petcock. Float setting seems OK (same as 1,2 & 3). Could it be a cracked stand pipe in the bowl itself? It comes in small glugs... then nowt - not a steady flow. Stops when engine running at more than tickover? Any ideas?

 

[cmg]

I would think the overflo pipe is cracked.

 

[cmg]

Once u have insured the float and needle are correct.

 

[mrtwowheel]

About 33.3% of the time when I rebuild or clean carbs I will have a float stick down for no apparent reason. Some taps and knocks on the bowl with the butt of a screwdriver and it never happens again.

 

[cmg]

2 of 4 carbs on my 79 had cracked over Flo tubes.

 

[The Orcadian]

2 of 4 carbs on my 79 had cracked over Flo tubes.

Yeah, I think that’s it indeed. Gonna remove the bowl (easy with carb 4 as good access). Did you manage to replace the pipes or do I need to hunt for a new bowl?

 

[The Orcadian]

About 33.3% of the time when I rebuild or clean carbs I will have a float stick down for no apparent reason. Some taps and knocks on the bowl with the butt of a screwdriver and it never happens again.

Thanks for that. I did check the float and seemed to be moving freely. Cheers

 

[cmg]

Soldier I think is best but my hands were to shaking. I used jb steel stick.

 

[cmg]

Let me know if you need details on what and how I did mine

 

[The Orcadian]

Soldier I think is best but my hands were to shaking. I used jb steel stick.

Have never used Steel Stick before but think I will give it a go! Will shout here if it fails