base gasket leak

i have a 94kz1000 police with a 1075 bore and 10.5 compression pistons, APE 410 cams i can't keep the base gasket for speeping i've use a copper ,stock and a rubber/alum. one, still no luck all surface where 100% clean and i use high spot and got about 95%surface contact, I heard that 10.5 compression is to much for stock head studs need some advice don't want to spend good money on studs that a don't need.

i always spray both sides ofgasketswith coppercoat

did that done that

have you retorqued the nuts on the head?

Is your crankcase properly vented? It seems like you are getting a buildup of pressure in your crankcase, rings leaking?, which is forcing oil out the base gasket. I also have a leaking base gasket on my KZ1100. I will be sure to spray copper sealant on both sides of the gasket when installing a new one. It is the only bike I have ever had this problem on. I don't see how a 10.5 compression ratio would have an effect on your crankcase pressure unless you have a ring leak. On the other hand, I have never had to address the aftermarket cylinder studs as an issue either....chris3

Studs for sure. With all the disassembly you've been doing chasing the leak, the stockers are probably stretched past the max tolerances anyway. My 1075/10.5 hasn't leaked a drop with APE studs and nuts.

Is your breather clear? No offense intended, but I've seen some folks cap off the breather without understanding the impact. Ed

if it was the breather i would guess valve cover would be blowing gaskets out pretty hard

I'd say HD Studs. The stock ones were designed to hold to stock specifications. I have the HD studs on my bike but the head gasket is what started leaking. The one piece gasket I guess isn't the best design, maybe for those guys who drag strip their bikes and take them down every season.
I spoke with a few people and they said they used to sell the two pieced head gaskets. This time around I will cut the gaskets so I can use the stock o ring. You may want to consider cutting the gasket to use the rubber oring. Just a thought.

TerryK wrote:

Studs for sure. With all the disassembly you've been doing chasing the leak, the stockers are probably stretched past the max tolerances anyway. My 1075/10.5 hasn't leaked a drop with APE studs and nuts.

hd studs with nuts make a tight 42 ft/lb sandwich.....

Had a chronic leak in my 1000 that just wouldn't go away after original build and then again a year later. Hated having a trickle of oil dropping over the dyno cover onto my boot. I tried to retorque the head nuts and it never felt right as I thought I was going to break a stud or twist it into the cases. Next tear down I checked the stud height and found they varied amongst the same size. I opted to swap out for APE head nuts with properly annealed copper washers which worked great. Another solution was to add another washer (copper and steel) with a smear of gasket sealer between each to stop oil from transferring between them and using stock nuts. Good luck!

as a last resort, make sure the cases and bottom of the block are ture. they can be out of true from the factory.
I agree with making sure u have adaquit venting as well.