Cylinder head resurface, cam timing?

Thanks for the comments, nads.

I checked the ignition advancer, as near as I can tell its real close to TDC when it indicates.

In case I was using the wrong pin to start counting the 28 pins, I moved the intake cam forward 1 link. There didn't seem to be any binding or resitance so I put it back together. My compression jumped to 145 PSI on all cylinders. When I started it up though it sounded like a bunch of little hammers inside the engine (oops). I checked all the valve clearances again, couldn't find anything to explain the noise so put the intake cam back 1 link. I again checked all the valve clearances and nothing changed from before so I don't think I bent anything. It doesn't sound like a bucket of bolts now but the compression is back where it was (115 to 125). Hopefully no harm done.

I have spent a lot of time looking at the different cams, sprockets and top cam chain roller. It all looks the same.

Clearly the cam timing is off somewhere.

I have now stripped the tightening bolt on the cam chain tensioner however, so I may be out of action until I can get that fixed. In the meantime I believe I will get the degreeing wheel and adjustable cam sprockets.

Thanks and have a good Sunday!

Maybe I'm doing this wrong. I got a cam degreeing wheel and installed on the ignition advance bolt. First I checked actual TDC and set the TDC mark of the degreeing wheel and installed a pointer. I have rotated the engine through a number of cycles with a dial gauge on the #1 valve bucket (first intake and then exhaust)to indicate where the valve is opening and closing.

According to some other information on the forum the cam specs for the KZ900 are:
Intake Open 30 BTDC
Intake Close 70 ABDC
Exhaust Open 70 BBDC
Exhaust Close 30 ATDC

Okay so I got:
Intake Open 45 BTDC
Intake Close 85 BBDC
Exhaust Open 85 BBDC
Exhaust Close 55 ATDC.

So the valves are opening 15 degrees early and closing 25 degrees late????? What have I got screwed up?

Any thoughts?

Thanks much everyone.

I feel like the cam timing is off. Can you take a pic of the cams? Set timing at "T" 1/4 and take close up pic (with lighting) at exhaust cam and at intake cam. So we can see the marks on exhaust cam at head. If you moved the intake cam ahead 1 pin and got better compression, that makes me think that you had both cams 1 pin late. As the piston comes up with exhaust open the exhaust is being forced out, At tdc the exhaust valve closes and the intake opens to allow the new fuel in. Possibly when you moved the intake cam ahead 1 pin it allowed the closing exhaust valves to touch the opening intake valves, hence the clatter. The first pin is above the line on the exhaust cam sprocket that lines up flush with top of the head where the gasket would be. Always keep 28 pin spread between cams...TFH

Post edited by: tfh903, at: 2006/01/08 18:44

I've been trying to figure out how to post multiple pics but I guess it's beyond me at the moment. Anyway here is the advancer.

Okay that didn't work.

Exhaust cam sprocket.

Intake cam sprocket.

After checking into the proper method for cam degreeing I wasn't taking into account valve lash or lift. Without changing the valve lash and using .040 lift I now get:
Intake Open 6 BTDC
Intake Close 48 ABDC
Exhaust Open 45 BBDC
Exhaust Close 11 ATDC

Still chewing on what this means.

Have a good week.

That looks good. The first pin is the one above the cam sprocket bolt head, start count there. The 28th pin should be about at the 11:30 almost 12:00 position with upper roller bolted down acording to the pics in my book. I don't think the 28 pin should be where that dot is in the your pic on the intake cam sprocket. I'll double check on my bike (have to pull the cover off anyway to check my valve clearance)... Back in a while...TFH

I have another picture that shows the "28" mark.

Your cams look correct.. checked mine and they are the same, would post pics but they look just like yours..
Did you check the timing advance pin at the crank? Now I'm stumped!! Is there any slack between the exhaust cam and the crank? TFH

If you look at the picture I posted in the following thread it may make things a little clearer for you.

kzrider.com/component/option,com_joomlab...ew/id,14694/catid,2/

It's a really good illustration of cam timing and what you are actually measuring. It is for a 750, but the principle is the same.
.

Post edited by: steell, at: 2006/01/08 23:58