Very heavy smoke from exhaust of Yamaha Virago 250ccobviously smells of burnt oil.doesnt seem to have any rattle or loss of power just belches out blue smoke.

hi
White smoke is burning engine oil.
mostly when Engine oil is changed or topped up
little oil get dropped and when engine heats up. it burns the oil.
but once oil is burnt then no more smoke is there.

unless you have a leak
thanks

white smoke fuel blue black white smoke oil over fill oil will cause it getting to much fuel will cause it check carberator check oil

Black smoke is a sign that the engine is running rich. It is getting too much fuel or not enough air. Try running some injector cleaner through the gas tank after you check the air filter.

white were? the exhaust tip, or other spot, long pipe, name spot?
white, is steam or OIL.
oil smells like burnt oil and takes for ever to dispate
steam is water, and smells , sweet due to 50% glycol inside.
and goes away fast.
but all Gas engines make water at all the time running as a by product of combustion and for sure on cold days, some times full time cold
due to climate effects.
does your neighbors car smoke at same time, (look)
bingo , dew point.

all gas engine smoke cold started, (steam)

so first find out what it is,
take the dip stick out of a hot engine. stalled, drip it on the exhaust
see that smoke ,smell it? that is burning oil
now you know what you have, steam or oil. smoke.

is it heavy white smoke? generally means you are burning antifreeze. Do a compression check of all cylinders and inspect spark plugs for any signs of engine malfunction, let me know what you find

sounds like you have a broken piston ring

Sorry but this has happened to me before, you might have a blown head gasket. that is where oil and or water are getting in to the piston cylinder and causing the white smoke cause the oil and water is being burnt or boiled.take it to a shop unless you have all the right tools and knowledge to do this job. i cost me like $1500 labor and parts.

engine probly has some worn hardware or hoses--chec oil for any foaming to eliminate bad gaskets--valve guides or rings cud hav minor wear causin some burnt oil smell thru leakin exhaust

Repair the exhaust, and all the power is back.

bad injector stuck rings with carbon build up ty doing a top engine clean to free up rings, also check PCV valve to see if it is defective when you remove it and shake it it should rattle if not it's plugged. Black smoke is indicative of over fueling or burning oil. Is the oil black? Also burnt valves could do this, is it using oil? if not let me know so we check more items seems to me they had an issue with the PCV VALVE OR HOSE OR BOTH.