cam timing "correct" but intake opening early

Hey all.

Bike and engine, 1981 Kz650 csr
Dyna-s ignition and dyna 3ohm coils

Last time the bike was running was after a rebuild where I forgot an o-ring and ran the top end out of oil.
That problem is solved and oil is getting to the cams
Now I have a new cams and head from a supposed running 1982 kz650 off ebay.

Problem: I have a cam timing issue, I am getting blow by through the all the carbs right before top dead center. (cylinder 4 is the strongest and decreases from there). When i describe this to you i will describe what is going on in cylinder 4, right side of the bike. As I turn over the crank by hand the cam starts to depress the bucket for #4 intake before it reaches the T mark on the top dead center, I would say it reaches it a little before the F mark. This is causing blow by. It's like I need to turn the cams counter clockwise at least 1 tooth.

I have checked my valve shims and my timing makes are level at the TDC mark and 45 pins between and 46 over.
pictures show my timing at TDC.

I have checked my valve seats by taking off the head and having the upside down head hold lacquer thinner without leaks through the valves.

So do I need slotted cams sprockets to make up for this or is something else wrong?

Do you have a Kawasaki Service Manual? Your exhaust cam appears to be in the wrong position compared to the picture in my manual, but my manual is for the 1980 KZ650. Ed

I'm not 100% sure since both cams are not in the same photo, but 650ed may be correct.

jarlef z650 . pdf is in the Files section.

1981 KZ650-CSR. Timing advancer set to the T mark then valve cover removed.


Then crankshaft turned a little, taking up the slack in the cam chain.

Something's definitely wrong since the exhaust valve should still be open as the intake valve opens. So there should be no cylinder pressure as the intake opens, when turning by hand. The exhaust has been open a while at that time.

The intake is supposed to be open just before TDC, by the way.

Like Ed said, your exhaust cam is in the wrong position. The 4 lobe should be pointing left and slightly more down in your photo. Either you have the wrong mark, or you are using the wrong mounting holes in the sprocket. Since Martin's photo shows the exhaust bolt using the hex outline, it's more likely you are using the wrong mark.

look at pic 1 camchain indented, and pic 2 under tension. Was the tensioner fitted?

look at the camchain 'fit' to the sprocket in 2. .. and trying to look closely at the sprocket teeth... something looks wrong there.

Also has the head been skimmed much? this affects cam timing quite a lot.

Adjusted the exhaust cam from the "IN" mark to the "Z6EX" mark and the bike started right up.
I thought I had checked the cams when before i put them in but must have only checked the intake cam, the exhaust cam sprocket was on different than the new cam. So instead of timing it to the "IN" mark the way I timed it before, i had to time it to the "Z6EX" mark. This makes since now because the exhaust stoke was compressing and when the intake would open it would release this pressure.

Very happy right now, been struggling with this for months. Thanks for the help everyone