Slight fuel leak from drain screws

I have a very light fuel leak from the drain screw on my carbs, i have replaced the copper washers but not with OE items, i just used plain copper washers. Can i use a Dowty washer or will the fuel eat the rubber in it? I do not want to over tighten the screws & risk stripping the threads

Only time will tell if the fuel would effect the seal. Do you guys still have pure Petrol? Or like us in the USA the Corn based Ethanol additive, i.e. Deathanol, it eats lots of stuff.

Yeah Motor Head, i was just looking into that the other day to see if anyone over here sold ethanol free stuff, no, its all 5% content

I've ordered some to see how it goes

Your drain screws have washers instead of o-rings?

Yes Martin, found that strange myself but this is the 1st old bike I've bought so I know no different. If there should bd o rings there can you point me in the right direction please, I know some o rings dont resist fuel that well

Is this fot the 77 750 B2? I don't see a listing for an O-ring on the drain from Kawasaki. If yours were to have an O-ring, there would be a groove on the drain screw where it resides, then the screw would be tappered on the end. I think yours are the ones with the washer, it is actually a Crush type sealing washer. Like a drain plug on a car.

That is indeed what is for motor head, i'll try those dowty washers & see how they go. Maybe the OE copper washers are thinner than the ones i've used or are a softer grade so they crush easier?