Exhaust popping while bike was running and found oil coming from air filter housing

You seem to have missed the air filter.

The problem is the the air breathers inside the rocker covers. Sad to say,but nearly all of them do this. One solution is to take off the air filter cover. There should be two bolts..(one on each side of the inside of the housing) that SHOULD have hoses hooked to them. If they do not have the hoses hooked to them,then that is your problem. See,these bolts are hollow,and have a nipple on the ends of them. These allow the top end to "breathe",a crankcase pressure relief if you will.Anyway,..these nipples are SUPPOSED to have a small hose on each of them,that re-direct the oil/crankcase pressure, into the carb/throttle body,which eliminates the oil running into your air filter housing.Check to make sure they are in fact there,and let me know what you find.

Regrettably, this is a common problem. You're engine is what we call a "Head Breather" meaning that the crankcase pressure is vented from the heads. And, as per EPA regulations, this vented pressure is directed into the air cleaner to be run through the engine. As the air is coming out of the engine, it brings with it small droplets of oil. These droplets of oil are caught in the air filter and coalesce into larger drops. The drops are then blown out of the air filter cover by the air passing by it as a result of the bike going down the road.

You can reduce this by keeping your air filter housing cleaned regularily. Or, you purchase a kit that will reroute the vented air from the crankcase. The air is vented into the air filter housing through the two large diameter bolts to the front and rear of the air filter. These bolts are hollow.

Good Luck
Steve

Only if the air filter has become oil fouled . More than likely this would keep the bike from running too. If you have too much oil be sure to do the sniff test (on the oil fill hole) just in case a carburetor float stuck and filled the engine with gas. This might also cause poor running. If you have oil in your gas be sure to change the oil , check the air filter, and always turn off the gas when you are not riding. If everything is normal , then you probably need to change the exhaust o-rings in the head and the exhaust seal from the head pipe to muffler. By sealing the exhaust system you should eliminate the popping and backfiring from deceleration.

When the carburetors over flow enough to fill the exhaust, It is possible that the gas also went into the cylinder and flowed past the rings and into the crankcase. With the engine overly full of gas and oil you could easily pop a seal or blow out a gasket. Check your oil level. If it is too full , change the oil, it will not lubricate properly with all the gas in it. Check that your shaft seal has not popped out. Check the air filter, the breather may have blown oil and gas all over it when you started the bike. Empty your pollution tubes behind the motor( they will drain the air box). Get in the habit of turning your fuel petcock off when not riding. This gas flooding happens randomly in certain models but can happen to any one.

the grey smoke is more than likely the air filter being blocked by the oil, it also sounds like unburnt fuel, check your choke ect to see if its seating properly, give the air filter a clean, then see if any more grey smoke appears (it'll start again when oil clogs it again). also check the exhaust system for a blockage e.g. worn/old gasket ect. change the oil check the colour make sure no gaskets have gone. also put the exact amount in as stated in owners manual (too much oil=too much pressure and can seep through oil ring on piston and leak into air box and make your bike run rubbish. hope this helps, it might not but worth a try.

They could be related - but what you need to do is first clean out the oil that has collected in the air filter housing - and replace the air filter. Then, clean the oil from the engine - Simple Green and an old tooth brush works great for this. Wash the engine and surrounding areas with soap and water.
Now, with things cleaned off, you'll be able to tell where the oil is coming from after a short test ride. It could be that the oil you saw near the head gasket was actually running from the air box. Hopefully, a new air filter will cure the problems you had with low power and poor throttle response.

Sounds like the carb has not been cleaned properly, gas overflow like that could be caused from a worn seat/needle. Did you put after market exhaust on it?

Oil in the air filter could mean tht the piston rings are weak thus throwing oil from the breather to the airfilter via the breather pipe.
Some filters do require a little oil like thK & N ones maybe in your bike it was over filled if at all.
You can run the engine with out the air fliter and see if theres smoke coming out of the breather pipe, if it does thn you will have to replace the piston rings or more over rebore the block and replace the piston kit.

Hope this helps !


Knight.YamahaSeca XJ750A 1981)