TOPIC:

Hey ya'll,

New to the site and the motorcycle world in general. Found this site and it has been incredibly resourceful and overall kick ass looking at all the KZ's and what everybody does to them. I just bought my first bike and she's an '81 kz1000 j...a big'n. Bought it from a friend for $1,000 about 5 months ago and i'm in love. It was well taken care of and had 9k original miles...barely even touched. I have already put over 2k on it myself in 5 months.

The bike sat for about 3 years before i bought it and right away I did a new battery, oil change, spark plugs and superbike bars with new cables. About 2 months ago I noticed it had been burning oil. after about 1000 miles of the oil change it had burned a whole quart worth. There were no noticeable leaks anywhere, didn't drip at all anywhere or anytime i parked it. I didn't notice any smoke coming out the pipes and there was no residue on the inside of the pipes. all 4 Spark plugs were dry and looked tan, not black. I eventually noticed there was a leak on the left side of my head gasket. It only leaked at high rpm's when i was riding and was definitely not enough to be a quart worth. I re torqued the head and the leak went away and i seemed to get a little better compression. Then when I rode with my neighbor he rode behind me and was really paying attention and noticed blue smoke comes out of the pipes at high rpm's and it definitely smells like oil. He is much more knowledgable than I am and has ridden many many bikes so I let him ride mine and he noticed it doesn't seem to have full compression or power right away at lower rpm's.

So its definitely burning oil and he thinks its the valve seats or oil rings? So I think i plan on doing a full top end rebuild if that is the case. Right now im running 10w40, and im going to do another oil change and put in 15w40 to see if that does anything before i tear into it. I just want to hear input from you guys. What do you think could be causing it to burn oil? Ive been recording and watching it and it burns about a quart every 500 miles. I have never pulled a motor apart by myself, but I am more than capable of doing it. How hard/simple is doing the top end? can i do it with the motor on the frame still, and what are all the parts / gaskets I will need? Any input you guys have is greatly greatly appreciated. Ive just been putting oil in as need be, but I would like this thing to run properly, even though she is running pretty damn good and fast as all hell still. Thank you in advance for the help guys

Beautiful bike!
They do demand attention...

I believe it is important to positively identify the source of a problem before trying to fix a problem. I suggest you run a leak-down test and run a compression test. The leak-down test should help you identify where you may be leaking compression (keep in mind it could be valves, rings, etc.). This should help you positively identify If the rings / cylinder walls are damaged and the source of the problem. The compression test should help you identify how much compression you are losing, but it won't show where the leakage is other than which cylinder(s) is leaking. Be sure to run the compression test with the engine at normal operating temperature; throttle wide open; a fully charged battery; and all spark plugs removed. Ed

Are you 100% sure your checking the oil correctly? I have seen people fill the oil to the upper mark with the bike on it's side stand.

Thanks for the help Ed! I will do a compression and leak down test to further find the source of the leak. I agree I would rather know exactly what the problem is before I open her up.

And yes Baldy, I have been checking the oil with it on the center stand and in my garage which is for sure level. I also put it up most of the time when I park just so I can monitor it better. Thats a good point to make though cause at first i didnt even think about it having to be level until me neighbor pointed it out to me!

Make sure you adjust the valves before spending time with a compression and/or a leak down test, otherwise you could be wasting your time if the valves are hanging open. Or just tear it down and measure everything. With only 10k on the engine the pistons and cylinders should be fine unless they are scored up for some reason. The valves should come out as a matter of course for cleaning and new valve stem seals so that should take care of that.

If you do the work make sure to only use OEM Kawasaki gaskets and rings. Aftermarket is a crapshoot and not worth the risk.

If you're not fouling plugs, I'd run it until it does. Valve guide seals are hard due to their age but you still have miles to go before a top end job. Do the compression test to be sure.
Steve

High oil consumption was common on the KZ1000J. A quart every 1000 should be considered normal, but a quart every 500 is pushing it. Probably needs rings and valve seals. They had a lot of problems with those early 1000s and 1100s burning oil. I had two top end rebuilds in 24,000 miles on a 1982 GPZ1100 when it was new back in the day.
Nice bike there, my dad had one and it ran really great. Wish I still had that one as well as the GPZ1100.

Thank you guys for all the help so far!

So i went ahead and put a heavier weight oil in it as it was suggested to me by a few people. I went from 10w40 to 15w40. Right after i changed the oil I started the bike and got it nice and warm to test the compression (as per the service manual). I tested the compression once from left to right, then did all 4 again right after that. I also waited for the bike to get completely cold and tested again. The "usable range" as per the service manual is between 121-188psi, and less than 14 psi difference between any 2 cylinders. These are the measurements i got after all 3 tests.

Warm 1: 125 135 115 121
Warm 2: 120 130 118 120
Cold: 125 122 120 130


I also am going to carefully watch the oil level and measure miles and amount of oil to figure out exactly how much oil I am burning. If you guys have any clue on what these numbers mean or any other suggestions, that would be super helpful. With me being a noob and all, going strictly off the numbers in the manual I would think my compressions seems fine. Im still getting a puff of smoke at high rpm's but am just going to keep riding it and monitoring carefully. Again thanks for the help so far and I really hope nothing major is going on cause I cant afford to not ride for a couple days to work on it

I knew I needed to change my valve seals, springs and valves. I bought each item including gaskets piece by piece. I also got some smaller shims in case I needed them. When I had everything I needed, I pulled the head and had it beck on the road in two days. I still have a ring issue and when I get a piston, I will put my 10.25/1 Wiseco's back in. I have new rings for them.
Not really the way to do it, but money isn't flowing like it did when I was working full time.
Steve