last owner overfilled oil......help!

Just traded my Honda CM450A for a 1981 XJ750 Seca. Was looking the bike over before I took it for a spin and the oil level window was black. Figured it may be slightly overfilled so I gently rode it to a buddy's place. When I got there the bike was dripping oil out of the bottom of the airbox!!!! We siphoned 1.2 litres of oil out of it to get it showing the right level! He works mostly on cars, but his advice was to take out the plugs and clean them well, install a new air filter (gonna need to learn how to do that), change the oil, and run a can of Seafoam through it to clean the engine and carbs, and take the bike out for a spirited run for a few hours. He also said to hop online and ask what to do in a forum.

What is the best way to remedy the situation?

How do I remove/install a new air filter?

 

Welcome!!

Sounds to me your buddy is on the right path. Just make sure the oil doesn't smell like gas. If it does the petcock could be failing or maybe its not on the vacum only setting.

Also, if the site window is black I'm assuming oil is black I'd change oil and oil filter.

I'm not sure about your particular model of bike but the xj650 maxim has a vacum operated petcock which are noted for failing and allowing gas to flood carbs and then into the engine and the oil then gets blown from crankcase vent into the airbox.

If I remember right the air filter is before the vent tube so if you have a new filter already on the bike you might be ok. If its like the xj it should be under the seat with four screws holding the top of the airbox on.

If it is a leaking petcock then a cheap fix is to get a briggs and stratton fuel shutoff for a lawn mower and splice it in between the petcock and carbs and just shut it off when you shut the bike off. Or you could rebuild the petcock theres a thread on here about rebuilding petcock. The rebuild kit can be obtained by sending a pm to Chacal the resident Vendor for xj4ever.com parts. He's got every part for xj's and he's an excellent guy to deal with.

Believe me people on here are more than willing to help. You've come to the right place. Someone will come a long soon who will know more about your particular bike.

 

Your air filter swap will be easy. Buy a new one and lift your seat. Remove the 3 screws on the plastic lid, below your fuse panel. 2 of the screws are easily seen and the other is near the tank. Gently place the lid panel aside and remove the air filter from the airbox. Inspect and clean airbox, install new filter and replace lid panel using the 3 screws.

I'd suggest working in a well lit area and having a flashlight - the inside of your black airbox is a very dark place. Take your time. Your bike may snort a bit as the exess oil works itself out, but after 15 minutes, no snorting and smooth whinning.

 

Thank you very much for the input. Going to start the clean up process tonight and will post results.

 

I wouldn't bother with the SeaFoam.

 

All of the above, And you might as well get yourself some new plugs, they're worth it.

 

Engine is sounding much better now. Thank you all for your input!