I have an oil leak and backfire on left cylinder

[socxs]

I have an oil leak and backfire on left cylinder that I need some ideas on what might be wrong. I had no issues prior to an incident where I lost my carb drain plug on my right carb. rode for a few blocks until the bike died and all the fuel drained out. I didn't know I lost the drain plug until I stopped I was testing the bike after rejetting to 40 and 135 jets. The bike is a 1980 XS650G with BS34 carbs w/ pod filters. Pamco Ignition (Timing is good) and green monster coil. I had an issue with the coil where the spark was jumping because the boot cam off but I fixed that. Any ideas on what might be causing the oil leak would be great. I am being told that I may have bent the piston rings.

thanks ahead,
joe

 

[gggGary]

Where is the oil "leaking" from?

Do you have healthy blue spark on both leads?
Just a reminder the high powered coils HATE not having a place to send the spark. Disconnected spark plug often = toasted coil.
Running on one cylinder for a few blocks shouldn't have done any engine damage.
More info, pictures?

 

[5twins]

Must be bent piston rings, happens all the time, lol.

 

[socxs]

I don't know where the leak is because I am running and I am getting blue smoke out of my exhaust. I was just hoping someone may have some insight into whether a problem in the piston could be causing the problem or if it would be something that happened in the head..

 

[5twins]

I've never heard of bent piston rings but I have heard of broken ones. When you run out of fuel completely like you did, the engine goes very lean for a while before it quits completely. I suppose it's possible you did some damage internally, especially if this happened at a higher speed, say like 55 or 60. The fact that you're blowing blue smoke now seems to indicate you've hurt something. Your only recourse may be to tear it down and find out what.

 

[socxs]

OK so a tear down is in order. I meant collapsed rings I just couldn't think of the word when I was writing the post. I have no place to tear the motor down and no money to do it right now either. But thanks for the info 5twins.

 

[gggGary]

What is your oil level? Does the oil smell like gas? Are you still using the vacuum petcock? Did you change the float valve O-rings? If it was my engine I would be doing a bit more snooping before I decided to do a tear down. What's the history of the bike? Miles on the engine? Has this been a regular runner or is it just "back from the dead"? valves set, cam chain adjusted? Do a compression test? What do the plugs look like?

Oil burning, not generally called a leak. often comes in around the rings or down the valve stems. A valve seal tear has happened before.

 

[XSLeo]

Oil can get into the combustion chamber from a leaky head gasket too. If the headgasket leaks between the cam chain tunnel and the combustion chamber. On the intake stroke draws oil through the bad head gasket. Then on compression tyhe oil seals the leak enough to run fine just burn the oil thatb gets pulled in.
I agree with gggGary, do a few tests before tearing it down.
Compression test, leak down test are both diagnostic tols.
Leo

 

[socxs]

Ok full history is that I have only owned the bike for less than 2 years and for the first 9 months the bike was not running. I had no issues before except for the ignition system not working. All the valves were set right but I haven't gone back in to see if they need re-adjustment. I have not done a compression test but my left cylinder spark plug looks like it came out of a two stroke motor and is black. I don't have any pictures but I will try to upload some later. I need to get the stuff to do a compression test but for now I am planning on going through all the steps you guys are talking about. On the issue of how long the bike has been running since it came back from the dead is only 6 months. I don't know the mileage on the engine and it was running good before this issue.