oil appearing at number four carb horn

[mini64]

i have what appears to be a fine mist of oil coming out of the number four weber horn. cant see it coming out, but after a race it is there. the car is a racer, meaning no breathers are venting to the air box/carbs, so it isnt coming from that. the oil is a fine grey coating (i use synthetic in it), almost like what is left on your finger after trying to wipe some moly lube off your hand). the mist has coated the air horn, gets the air box wet a bit and there appears a spray pattern on the firewall on this side of the engine bay. i suppose it is possible that the oil is leaking from somewhere else and getting sucked into the carb, but i cant find any other leaks. any ideas what may be causing this?

[iain.hamlton]

I see something similar, but assume it is petrol, or a something sticky in the petrol. It looks like oil; smells of petrol, but feels like a mixture of petrol and oil. Presumably, the volatile parts of the petrol will have evaporated. If it is petrol, I assume it is leaking or spat back from the carb, or coming from the vent-hole to the float chamber. Like you, I do not vent the crankcase into the air-box.

best regards, Iain

[kenny]

Similar to a x/flow screamer I buit a while back. That breathed away from filters ie. crankcase to rocker cover---out of cover to catch tank.

Yep loads of sticky oily mist around trumpets which I'm convinced was petrol.

Kenny

[mini64]

i took the venturi out and added a little sealent to where the secondary venturi gets the fuel from - this seems to have fixed things.

[elan_fan]

Bit of stand off probably, have you got wild cams and plenty of revs

regards
Mark