81 xj650 maxim top end rebuild, Anything else I should do with the engine out?

I am rebuilding the top end on my maxim. Do I need to take the engine off? I am assuming yes. Also, is there anything else I should do while I have the engine off/engine apart? I don't plan on doin this again! The reason I am changing the head gaskets is so it stops spitting oil on my nice jeans

 

By "rebuilding" I guess I don't know what exactly you mean other than replacing the head gasket as you mentioned. If you're taking the head off there really isn't any reason not to lap the valves and replace the seals while your at it.

 

you will be able to remove the head with out removing the motor from frame

 

Do you mean head gasket or just valve cover gasket?
The valve cover gasket is usually the source of oil leaks.

 

Yes, you can do it with the engine in the bike. Second on the above to lap the valves and replace the valve seals at a minimum, you're already there. Also, you should de-carbon the head and piston crowns and its a great time to set your valve clearances. To be 100% correct in addition to above the head should be checked for true-ness and the valve guides should be replaced.

 

Since you will hav some down time whil the head is done, consider going all-in and taking care of a couple of soon-to-fail components; the alternator chain guide (thy die from age), and the starter clutch (die from use and may as well be done when the alternator chain guide is replaced). Those aren't must-do's, but may-as-well-d0-them-now things.

 

These are all great helps! By rebuild I mean replace the valve cover seals and most importantly the head seal just above the base. I bought a top end seals kit so I was going to take it apart until I got to the one I needed and put it back together with the new seals. I'll look around for the valve timing info as well, I'm sure it is available somewhere on the forum. This IS my first rodeo so I can use all the advice I can get.

 

Is the head gasket leaking? Are any valves not sealing (when clearances are in spec)? If not,then there really is no reason to replace it, and therefore no reason to remove the head. Rebuilding a head entails replacing valve guid seals, re-gringing valves, replacing valve seats, and truing the head mating surface if needed. Unless you have a mechanical failure there is no need whatsoever to pull the head off.

 

The red is as far as I need to take apart the motor until, The last seal. The blue is where there's oil coming out. Only on the right two cylinders. I don't know about the valves. All i know is there is oil coming off and onto my leg. The bike runs fine ish, but it isn't very usable in the current state.(this is a stock photo btw, )

 

Or you could pop a 700 or 750 engine in to it
Where in Canada are you it's a big place
I have a couple of motors available
650 non yics and an 85 700n yics engine both are non leakers

 

The bike is in Manitoba. I didn't think of putting a new motor in because the one I have runs good.

 

If the oil is showing up only at the areas you colored blue, then it isn't likely coming from the head gasket. Valve cover gasket is the first suspect, followed by the special crush washers that lie under the two rightmost head nuts.

If the oil is only at the red line and below, then it might be the head gasket, or the cam chain tensioner gasket.

 

In your original post you said that the oil is 'spitting' onto your jeans. If it really is spitting out (under pressure) then it must be from the head gasket and it must be a pretty serious leak. If it's weeping out and being blown back on you by the wind then it is more likely the valve cover gasket. From there it runs down the outside of the engine and follows the seam at the base of the head, making it look like a head gasket leak.

 

The valve cover looks very clean on the outside. The oil starts where the carbs enter and the headers leave. You're right though, it is weeping out and blowing back. Also where the rpm meter goes in closer to the top of the block on the front there is quite a bit of oil.

 

The valve covers most often leak from the inner part of the "H" and the oil runs down the water-drain channels so it looks like it's coming from the head gasket.
The Tachometer drive has an oil sal that fails with age, and then it dumps a whole lot of oil out.
Tend to the valve cover gasket and replace the o-ring and oil seal on the tacho drive. Degrease the engine so you can see if that stops the oil problem before you so much as set a socket onto a head nut.


Tach Gear Housing Oil Seal replacement w/pics

Valve cover gasket is covered in here. Keep in mind though that your '81 has a paper valve cover gasket and two rubber half-moon seals. I think installation of that type is also in that thread, but I forget.
AIRHEAD VALVE ADJUSTMENT with Pics
Check valve clearances while you have it off.

Start a conversation with Chacal for parts.

 

Not necessarily. A bad tachometer drive oil seal will spit a hell of a lot of oil, as will a missing chunk from a valve cover gasket, or a half-moon that's cockyed.