1982 XJ650L Turbo - Carbs Overflowing

How much fuel pressure do the carb needles and seats see at idle?

I understand that the check valve opens about 2.8psig, and have seen references to automotive FPRs having a 6 psig set point. My FPR, with a gauge between the pump and the check valve, tests out at 5.3 psi.

But I have a horrible overflow problem. Static float height set at 17mm and verified on bench with gravity fuel at 2mm below the gasket surface. I've since found that 21mm is supposedly the magic starting point for adjustment I will go back to that setting and try again.

I am not sure that the floats in the carb are OEM which could be a problem. Can anybody post photos of the oem float assembly?

And the tang on the float assembly pivot which limits 'float drop' in the bowl without fuel, to prevent the needle from falling out of position: How far should the float be allowed to drop from the valve just being closed?

 

As far as I understand it, you're way better off doing wet measurements, instead of dry measurements. So, yes, you can use the tang as a means of adjustment, but it's not recommended here to do so

 

Do you have an OEM FPR?
Mine measured right at 2.8 psi
I wouldn't dismiss your higher pressure for the flooding issue

 

He did

 

When I had a similar problem with a Turbo the problem was the "droop" tang on the float and the non-OEM float needles. The droop was just enough to allow the aftermarket float needles to sag just enough to not be square in the bore. I worked for about 3 weeks to get the wet set on the bench done. Sorry, no, I don't have a measurement for the sag or droop. No, I didn't figure it out by myself either, I found it on the internet...... Good Luck, when I got it right it was worth the time it took to get it right.

 

Thanks for the reply. Yes, it is an OEM FPR. Non-adjustable. There was a Holley FPR kit for similar design Denso EFI FPR's, but the diameter of the diaphram is larger for low pressure carbureted use. Fuel injection at psi pressure can get away with a smaller diameter and stiffer spring. So that means no kit for this FPR

The OEM FPR is packaged specifically for this bike. Generic aftermarket FPRs are quite a bit bigger overall, and hose routing becomes a problem.

I'll try resetting the floats first.

 

Thanks for the reply. I'll check it out and advise. Still looking for photos of OEM floats to see if these may not meet spec. There is so much Chinesium out there you just never know unless you have OEM.