Major Oil Leak on a 1983 XJ-750 K.... Help desperatly needed

My bike is an 83 XJ-750 k, it had sat for around a year before I bought it. After I had cleaned the carbs and rode the kinks out of it, I noticed a small pool of oil on the top of the Crankcase below what I believe is the stator and the left side of the engine. It was originally a small leak, and gradually corrected itself over time and miles.

Today I started My bike and let it warm up before I took off, and there was a HUGE puddle of oil there, and no more oil left in the sight glass. It drips oil on the floor below it.

The general concensus is that it may be coming from the crankcase gasket, however I one time noticed oil dripping from the bottom screw of the stator/generator. No one is 100% sure where it is coming from

Please any info is helpful

 

Your rotor shaft seal is probably shot. Pull the rotor and verify the oil leak before you proceed further. You will need a new rotor shaft seal, the seal carrier O-ring and a rotor removal tool or a M16 x 1.XX thread (someone help me remember this spec please) bolt. Replacement is a very straight forward process and easily done in an hour.

 

Or it's overfilled and oil is coming out the airbox drain. If you start an XJ and then shut it off right away or within a couple minutes there WILL NOT be any oil showing in the sight glass and it will take a good 5-7 minutes before the (cold) oil will drain back down and fill the bottom up again. Don't assume you're not seeing oil in this situation because it all got pumped out.

What "crankcase gasket" was General Concensus referring to?

I would not jump to any conclusions it's an OLD BIKE. Pull the alternator cover (it's a good idea to at least LOOK at your brushes) and see if the bottom of the housing is full of oil. Look in the airbox. If it IS the stator seal, it's an easy fix like Robert said.

You're lucky if your '83 sat for only a year. Mine sat once for 7-10 years, then got halfass resurrected and then sat for 4 more years. Inside luckily, but it still took its toll.

Have you checked the date codes on your tires to be sure you're not riding around on ancient rubber?

Did you have a look at your rear brake shoes yet? VERY IMPORTANT you do so soon: http://xjbikes.com/Forums/viewtopic/t=15874.html

 

first of all what is and where is the rotor shaft seal, this seems like a logical explanation

No, the oil was definatly gone, I know that your supposed to let the oil come back down, due to the vaccum.

it hasnt been over filled either, as I just recently changed the oil, and refilled according to the shop manual specs.

I put new oil in it, and cleaned the whole engine. I then allowed it to idle for 15+ minuets to see if I could spot a leak anywhere, there was nothing. Then I took it for a short ride, to stress the engine some, checked again, and there was still no leak.... wierd.

The gasket that I think is the problem is the crankcase cover gasket, which I am now more confident that that is the problem, as the degreaser revealed a great deal of yellowing on the case where there has been a leak before.

I had to change the float bowl gaskets when I baught it, because they were dried out and extreamly brittle... the same could easily be wrong with this one...

any thoughts?

Thanks

 

Take the Cover off the Alternator.
The Round Cover to the left of the Starter.
3 Cap Bolts (Allen) hold it on.

Examine the Inside of the Cover and the bottom of the Alternator Windings.

Let us know if the area is Oily or dry.

 

it is dry

 

That sort of rules out the rotor shaft seal.

Is the bike on the sidestand or center stand when you're seeing no oil in the glass?

And which "crankcase cover" gasket do you keep referring to? Yamaha calls them all "crankcase covers."

 

Good! What about under the Bike? Is there an Oil Stain? Pool?

Anything requiring the notification of the Environmental Protection Agency?

 

the crankcase cover that Is troubling me is the one on the left, under the stator. I'll have to remove the shift lever to get it off. Im fairly sure that is where the leak is from, but I wont be positive till tomarrow. Im going to take it out on a ride to put it under some stress. I replaced the missing oil with castrol 20w-50 oil.... it doesn't so readily leak now, with thicker oil.

When I cleaned the engine, I discoverd some significant oil yellowing on the case, tipping me that maybe their has been oil leaking from this area before (There has been small pool of oil under the bike, starting today)...

The guy that i bought the bike from was pretty lazy. Rather than fix the bike, he parked it and bought a brand new kawasaki 1100 of some sort. he never did any work to the bike, I am convinced he never even changed the oil, it was DARK black when I changed it, and the oil I just put in it is already extreamly dark black in the sight glass. I am going to run some seafoam through the oil before I change it again. I have already ordered the crankcase gasket, whether or not this is my problem, this will help in some fashion.

 

I really apreciate all of your interest, I love my XJ and hopefully I can become a productive member of this community.

 

If you pull that Cover and replace the Gasket ... do the Shifter Shaft Seal too.
Just for good measure.

Be careful putting it back on.
The Pigtail for the Ignition Pickup Coils runs under a little Cover at the Top Left of that Cover.
Be sure the Pigtail is NOT being pinched when you Bolt-on the Cover.

 

good deal. What is the likelyhood of the oil pushing its way up like that, seems like a pretty easy accomplishment. Would I be wrong?