1982 XJ750 Maxim Burning Oil

Hi All,

My 1982 XJ750 Maxim seems to be burning about a half quart of oil every 100 miles or so. The spark plug for cylinder #4 seems to be getting oil on it, when I pull it after the 100mi ride it is wet.

Back when I purchased the bike cylinder #4 was a bit rusty and needed a soak with "the juice" to get it moving, so I assume the oil getting into this cylinder is related to that somehow.

I recently did a valve check and re-shimmed them to be within proper spec. Compression test gives about 140psi on all 4 cylinders which i understand to be low but within spec.

Any ideas on why she is burning so much oil?

Thanks!

 

If #4 was a little bit crusty, then my guess would be the rings are stuck.

If it were my engine, I would first try to unstick the rings chemically, like this guy:

Basically, try to get the rings soaking in B12 and free them up.

If that doesn't work, then you'll probably have to do it the old-fashioned way (disassemble and clean).

How many miles are on the bike?

 

Thanks. stuck ring was my thought as well. Already tried the soak with ATF/acetone mixture to no avail. Can't hurt to try this B-12 product before taking it apart.
It has about 27k miles. Had been sitting for a couple years outside when I bought it.

I'm wondering though why would I get 140psi on all 4 cylinders if one of them has a stuck ring. Wouldn't cyl 4 show a reading that is out of spec? Anything else you know of that could be going on to cause that much oil to be burned?

 

My thought process was that the B12 would be better for loosening up the carbon in the rings - whereas the ATF/acetone seems to be more about loosening the rust/corrosion. It may be a combination of rust and carbon making the rings sticky.

 

Well after watching that video I'm sold lol. Gotta give it a try. Thank you for the tip.

 

if its just the oil scraper ring thats stuck, that would be the reason of burning off oil , but still give a decent compression reading

 

That would make a lot of sense