Vf500F Starving For Fuel

As some of you already know, I got myself a 1985 VF500F. Well its made 1985 by the frame number, but technical its a 1986 model, as it don`t have a fuel bump! I have a problem, the bike starve for fuel at times.

So someone kindly did give me this link.http://www.daugherty.../tankvalve.html

A thing I might do, but seem this is a problem for bikes whit a fuel pump, my do not have a fuel pump.

I have had the fuel tap/pet cock up, the screen was clean and all seem in order. I have tested the fuel cap, it let air pass the small hole, tested whit compressed air. After the check the bike did run fine for about 300km, then rideing to work today, it started to starve for fuel again, turn the pet cock/fuel tap to reserve didn`t help. But turning the bike to left side, like rideing a left curve did help. Did stop at first petrol station to be safe, filled up 9,3 liters.............it should be a 15,5l tank, so how mutch is for spare/reserve?3,5l? I have filled up ~12l at most whit out hitting reserve. Anyway after the fuel stop it did run fine again the rest of the day.

So suggestions where to start to look next? Something in the tank that sucks into the screen of the fuel tap/pet cock?

Ideas are welcome. 

And one more thing, my bike is a Swiss market bike.............

Hi Keny, the fuel tap issue affects non-fuel pump bikes too. Definitely worth a check.

Did you check that fuel flows from the fuel outlet at both run & res marks on the tap ?  If yes, should be the same rate. If not there's a blockage.

Check the fuel line to the carbs, sometimes people change this for a longer or different one makes fitting the tank easier, but when the tank is down the longer hose links & limits fuel flow as the head height in the tank goes down there is less pressure to push fuel through the restriction !

Thanks guys!

The fuel lines seem orginal to me, not much you can rice the tank for taking it of the fuel tap.

And yes, as I had the tank off, did check the fuel runs in both "on" as "res" mode, and the vacum opener did work as should.

A thing I did not do was drain the last fuel the tank had in it.....maybe I should have........