Here is a tough one!

you said early on that the plugs were brown, and no oil on the top of the pistons,,, tells me its not from blow by or guides, the plugs would be wet and the pistons would be black.
using/leaking a quart of oil in 120 mile is a hell of alot.
since you have the head off, fill the top of it with kerosene or some other light solvent, and let it sit, you should see if something is leaking real quick.
My thought here is maybe the PO cracked something around the ex, area and that is why its using that much oil and the pistons dont show it.

one more thought, its not over full is it?

Pulled the cyl off at lunch, everything still looks good, no abnormal wear, no ring gaps lined up, will try the kerosene trick.

did you remove the valves?? how do the look like on the valve and valve stem?? can you make a pic??
my z1200 makes 185-195 psi warm engine with hotter cams...

OK dont have the valves out yet but I did the kerosene trick and found out 2 of the emission hole plugs were loose, the other thing I noticed was that the base gasket is tight on the outer rear studs, correct me if I wrong but is this not where the oil gets to the top end?? I took some pics to show every one what I am looking at. So far the loose emission plus the lack of an cam chain galley O ring and the weird base gasket are the only things that jump out at me.
The 5th pic is a comparison of a new base gasket.
take a look:

maybe im crazy but it looks like the o'ring is there for gallery.its a little late to diagnose things now but as long as its apart id check pistons and bores to make sure theyre round,then id drop the rings in bore and check end gaps and work my way up from there.if the motor has a smog motor head 79 or newer is it possible the motor is sucking oil through exhuast ports into emmision sysem when bike warms up and burning it?id also check the valve guides for wear,rocking the valves in guides without springs is easiest way i know to check them.

those pistons look like there pretty clean to have been burning any oil like your talking about i still would be looking for a hole or a crack in that oil gallery on the exhaust side. as far as the head replacement goes all you have to do is install the upper cam chain idler and you can use the same cams and sprockets just follow your instructions and it will be easy. i just did that conversion on my 1393cc drag motor. by the way those pistons look pretty wild for the street.

i figure as long as hes got it thisfar apart cant hurt to measure things.:laugh:

timebomb33 wrote:

those pistons look like there pretty clean to have been burning any oil like your talking about i still would be looking for a hole or a crack in that oil gallery on the exhaust side. as far as the head replacement goes all you have to do is install the upper cam chain idler and you can use the same cams and sprockets just follow your instructions and it will be easy. i just did that conversion on my 1393cc drag motor. by the way those pistons look pretty wild for the street.

I know they are 12:1, thats why I want to go with a J model head, to lower the comp down to around 10:1

I am more convinced now that the oil problem is not in the rings or the valve guides, if it was there would be so much oil on the valves they would almost slide out on thier own.

I am not 100% convinced that those are 12:1 pistons, maybe someone more familiar will correct me, but either way as plummen says, check to bore, do a light hone on the cyls and replace the rings, along with a valve job on the head.
This way when you put it back you know its right

140 psi compression isn't all that great on a bike with 12:1 compression pistons as has been noted. Not sure if the low compression is related to the oil consumption issue but I would buy a digital caliper and some bore gauges. A shop manual will tell you to check the cylinder bore diameter in 3 depth levels and at different angles to determine if the holes are round. I would measure the piston diameter as well and determine if the piston to bore clearance is within spec. Don't take anything for granted as the machine work may have been faulty. It is also possible that the pistons have been rocking and have ovalled the bores. On 79/80 cylinder heads, there is a passageway from the reed valves to down into the exhaust port runner. Some have suggested an oil leak here. It is more likely that someone did some amateur porting and knicked the oil journals which are the areas around the outer cylinder head studs. This would cause excess oil in an area where it gets blown out the exhaust but that is a tad unlikely as it would be a mess when you opened up the engine. Using a quart of oil every fill up, it should be pretty apparent where the oil is coming out... If it is the pipes, they will be greasy with oil. If it is the crank breather you will have a bunch of oil all over the area where the crank vents. If it is a leak, you should see BIG drops and puddles. Could the bike be leaking?

BSKZ650 wrote:

I am more convinced now that the oil problem is not in the rings or the valve guides, if it was there would be so much oil on the valves they would almost slide out on thier own.

I am not 100% convinced that those are 12:1 pistons, maybe someone more familiar will correct me, but either way as plummen says, check to bore, do a light hone on the cyls and replace the rings, along with a valve job on the head.
This way when you put it back you know its right

I called Weisco and gave them the numbers off the tops of the pistons, they said 1075cc, 12:1

OK pulled the lower end out of the frame, pulled the pan off, everything looks fine, so I am going on the assumption that the problem is in the head, the cylenders and pistons all look and measure what they should, so I think if I put another head on it and call it a day, now to find a nice J model head, to lower my compression!!