Here is a tough one!

I decided after now using a quart of oil per fill up, (every 120 miles or so) I should figure out where it is coming from. So I yanked off the head of my 79 kz 1000 tonight and found...
NOTHING! the bores are spotless, the pistons are clean the plugs perfectly light brown, no odd deposits of any sort. but running down the road it looked as though I was spraying for west nile! the bike had 140psi in all 4 cyls, the only odd thing I found was there was no O ring where the timing chain galley is, just some hi temp black rtv. so can I assume the valve guides are that shot?? Strangely enough the bike only smoked when hot, and did not have any blow by out the breather and did not smoke while decelerating. I have been around engines all my life and this one has got me stumped!!

What I did find out is the P.O. lied to my about the work that had "been done"
he said it was a 1150cc
when I said do you mean 1105? he says yes and it had bug cams and port work done, the reality is it's a 1075cc but has 12:1 comp>>> hence why it wont run on pump gas!!! Stock cams and some port work that looked like my 3yo daughter did!
So what now? need to lower compression and find out where the oil is comming from
any ideas out there???

look in your exhaust ports where this guy did his port work and check to see that he didn't punch thru the oil gallery on the exhaust side .is there oil in the pipe because thats probably were it will be coming from. this happened to a friend of mine that i had done some head work for he decided to go to bigger cams and when he looked at my port work he figured if some is good lot's is better . so he got in there and hogged out a bunch more and just barely nicked the the oil passage we cleaned it up good with brake cleaner then j-b welded then let it sit over night and it was good as new then we welded it up come winter . as far as i know he is still running that head on his dragbike. .

Yes, the pipe is wet, but the exhaust side of the head does not look like there has been any work done in there.
I think I'm just going to look for a J head and leave the rest alone, according to what I have found using a J head will get me down to around 10:1 which is where I need to be to run pump gas.

I am sure you know that a J motor uses a hyvo cam chain. You need to buy an idler assembly that will fit the J head that uses the bicycle cam chain. APE sells them as well as a jig for drilling the J head to install the new idler assembly I think.

If the combustion chamber looks clean, consider a leak from one or more of the exhaust valve stems straight into the exhaust. That would account for the excessive smoke/oil fog.

Could be caused by an excessive exhaust valve stem or valve guide gap or just needs a new rubber valve guide seal and spring.

Best of success.

wiredgeorge wrote:

I am sure you know that a J motor uses a hyvo cam chain. You need to buy an idler assembly that will fit the J head that uses the bicycle cam chain. APE sells them as well as a jig for drilling the J head to install the new idler assembly I think.

Yes I did know that , but one question is because of the chain differences, can you use the j head cams with kz gears or can you put kz cams/gears in a j head??

From what I read, it doesn't smoke at startup?

Later, Doug

here is the info off of apes site.
www.aperaceparts.com/tech/techkz1000.html
hth

Correct, no smoke untill warm, running down the road at speed, which in my eyes rules out guides???

zombiescustoms wrote:

Correct, no smoke untill warm, running down the road at speed, which in my eyes rules out guides???

I would think. But the other thing that came to mind is you only have 140psi with 12:1 compression? With stock cams you won't have a lot of overlap so the cams won't affect compression that much. I'm guessing rings even though the bores look fine. Maybe they lost tension from too much heat? Can you do a leak down? That might tell you something.

Later, Doug

little late for a leak down, head is off, I will be pulling off the cyl tonight. And you would think with weak rings= blowby from breather, which there is none. What would you think the PSI should be with 12:1??

zombiescustoms wrote:

What would you think the PSI should be with 12:1??

Well atmospheric pressure is 14.7psi so 14.7psi x 12= 176.4psi. That should be your theroetical pressure. So if you measure 140psi you have a 20% loss of compression somewhere. Granted this is all ideal but gives you a general idea.

Later, Doug