oil in the carb?

Any ideas: the bike won't start. there's a strong spark and the timing is spot on with a tank of fresh petrol. I took the carbs off which are new amals and found what looks like traces of oil in the right hand (gear box side) carb body?

Cheers

Steve

Wouldn't have come from the breather would it?
That goes into the air filter around that area.

Has the bike been running at all? I would be checking to see if it was sucked out of the air filter via the tank vent (if overfilled), or I would be wondering about what was in the fuel tank (possible oil on right hand side of tank ingested when tap was turned on). If it came from the head...I am not sure what to recommend, it would imply some leakage and that the oil was flowing against the usual direction of vacuum. I would pull the carb and intake off and look at the port to see if there any sign of oil there.

Russ

If not just breather vent oil misting from factory set up, then might be leaky intake valve guide misting backward on intake reversions at valve closure.
Don't forget to try a few set of spark plugs, one just never knows and even if not the issue you will feel useful and cleaver before any real straining of failed solutions starts.

hobot

Thanks Chaps, I've had the bike running briefly but it wasn't as sweet as it should have been. I've looked in the port and although it's not clean there was no oil to speak of. I washed out the tank with fresh petrol before trying to start it so I know that's ok. I'll check the oil level tomorrow. I'll try your suggestions and let you know how I get on. I'm going to kick the cat now. Cheers, Steve

It is probably something simple. I'd suspect fuel. Is it flooding, i.e. are the plugs or ticklers wet ? Does the bike tickle normally ? If you have new Amals, have you checked the float levels ?

If you have the float bowl in your hand and the fuel line hooked up, the top of the float should be at the top of the bowl and the fuel level about 3/8" below the lip.

Greg

The carbs tickle ok, there's no problem there but I haven't looked at the float levels, I'll check those. That's another half an hour with a cut down allen key to get the carbs off. I've had a problem with wet sumping and I've just fitted an anti drain valve from Mick Hemmings so it won't happen again, but is it possible that the oil in the carb came from the wet sumping in some way? Obviously this would have happened prior to fitting the valve. What do you think?

Cheers, Steve

With factory air box and breather from the oil tank it's very common to overfill the tank and have oil fill up the air filter then get sucked into the carbs. Engine will run like crap under load (DAMHIK). Check that your air filter isn't dripping in oil.

If you have a non-stock air filter arrangement then ignore this post.

When both pistons go down case PSI spikes up and can force oil to weep out about anywhere but into carb intakes. Its good idea to install the one way breather vent valves a search here will cover, then have to spray factory nuts with clear coat for rust protection.

Carbs should give best idle with idle-air-pilot screw 1.5 turns out.
Low float mean less gas mean less air needed mean less screw turn out to idle.
Diddle floats to this ideal for best carb base line to tune from or fix what is preventing this approach to idea 1,5 turns.

If oil leak is significant on that side the muffler of plug and piston surface may reveal it by blackness instead of dark to light gray-ness.

A slightly sooty plug end rim is good sign if not also soot the center electrode.
New gas blurs classic plug chop readings. Classic carb tune ends up leaner than tradition with new gas formulas in the tank.