Topic: Is fuel flow the same flow rate across the dual barbs petcock?

[DesertKyorugi]

I just rebuilt the petcock off my 71 JDM CB750 and was checking for obstruction. I noticed the rearmost barb is flowing faster than the forward barb. Is that supposed to be correct or am I having so blockage issue? I blew compressed air into both barbs and still get the same results

[seanbarney41]

Try this when observing flow...plug one outlet and it all comes out the other, plug the other outlet and it all switches to the first.  Fluids are gonna take the path of least resistance.

[BenelliSEI]

...... and what you observed is “normal”.

[DesertKyorugi]

...... and what you observed is “normal”.

Very interesting.....that means I have the fuel hoses routed wrong on my other 71 K1. I should route the rearward barb to carbs 1-2 instead since it has the longer route. 

[Don R]

  I had once considered porting the slower flowing side but try to avoid fixing non existent issues. Desert may have it right, the longer hose could use a head start.

[BenelliSEI]

But here’s the thing; if you even slightly restrict the flow at the pipe that appears “more”, the other one’s flow will increase. We’re only topping up the float bowls, at the rate fuel is being consumed. There is plenty of volume, and it get’s shared as required (assuming your filters are clean and openings unobstructed). Also, make sure the fuel cap vent is clear. If it’s plugged, nothing works.

[DesertKyorugi]

But here’s the thing; if you even slightly restrict the flow at the pipe that appears “more”, the other one’s flow will increase. We’re only topping up the float bowls, at the rate fuel is being consumed. There is plenty of volume, and it get’s shared as required (assuming your filters are clean and openings unobstructed). Also, make sure the fuel cap vent is clear. If it’s plugged, nothing works.

I have clear fuel filters on my running K1. The right bank filter always gets filled up first, which I contributed to having a shorter route but now I know it is both shorter route and faster flow.

I will switch the hoses and see if it allows both to get filled up at the same time