Cold start OK but after while motor stalls Hilfe

[ErwinC]

Hello all please help me
My xf650 starts OK when motor is cold but after a few minutes stops.
I noticed some smoke just before stopping, problably from the tube that comes from the carburators and Just hangs down (not connected to anything )
When motor is warm the engine stalls and can not be started untill a few hours of rest.
I allready exchanged the carburators for a secondhand set. Same result.
Tonight i noticed that the oil level raised from just above "full"to completly full (glass was totally covered )
Oil is Brand New.
Maybe the fuel is entering the engine compartment but i really do not know why and how.

Greatings Erwin

Answering in German is OK, in can read but writing not so good

[AoS]

I'm not so sure about the starting problem, I'd check all the usual suspects first, air filter, spark plugs, valve clearance. But maybe somebody has got a better and more direct solution.

Can you tell which smoking hose you mean? Actually, none of them should emit any smoke, and most on the carbs should be connected to something. If I remember correctly, then there's only one open hose, it is fairly large and points rearwards to the airbox. That's the pressurization for the carbs, it mustn't smoke.
There two more hoses which lead to the ground, but those aren't connected to the carbs. One is the spillover from the air filter, the other from the filler cap. The former is usually plugged, and both mustn't smoke as well.

But to the issue of the rising oil level: Just smell for fuel. A little smell is okay, but diluted oil smells distinctly of fresh, unburnt fuel. If it smells, don't start the engine. If it doesn't, the level may have risen because of oil running back from the cooler or because the bike wasn't standing on level ground.

Dirk

[ErwinC]

Thank you for jour reply Dirk,

I started the engine without airfilter to be sure that this was not the problem.
Spark plug i didn't checked yet. Are there any signes where i should look at?
Spark gap, color etc?
The sparks itself looks healthy.

Valve clearance was last checked less than 1000km. Should i check again you think?

Which hose was not clear the smoke could also have been an oil stain which was smoking.
There is a hose that is called "air vent hose".

Oil smells very little of fuel.

[AoS]

A little smell should be fine, but I'd keep an eye on that.

To the other matter: I'd check the valve clearance again. The valves don't seal if the engine is hot and the gap on the exhaust side is too narrow. That might be the case.

Dirk

[FJD]

the reason is for sure: leaking gaskets at the flaot valve seats (these are O-rings).
Had the same with mine, new O-rings helped, old ones were har and brittle

[derPeter]

I never noticed a hose dangling from the carbs on my XF650...
r u sure this hose should'nt be attached to something "carburatory" ?