exhaust valve positioning

mcoker · Apr 13, 2003

I'm re-building the top-end on my '88 kdx 200 for the first time, and I pulled the cylinder exhaust valves out and cleaned them. They were caked with carbon, but I got them clean... and as per my Clymer manual, I'm putting them back in. However, the manual says that there are markings on the cylinder that should line up with punches on the exhaust valves when I put them back in. I see the punches on the valves, but I don't see any markings on the cylinder to line them up with. I read online that I should put them back in so that they're "closed" but, having never done this before, I dont know what that means. Can anyone provide some insight?

MX175 · Apr 14, 2003

I don't think you need to align any marks on the cylinder. Just put the marks on the valves toward the front. Because the valves are back away from the cylinder wall, it is hard to see when they are closed without a mirror. The left one can been seen from the exhaust header, but you can't eyeball the right one without a mirror. It is worth it just for the peace of mind that they are in the proper position.

hasBen · Apr 14, 2003

mcoker I ran into a similar problem when I rebuilt the topend on our '86 KDX200. The information in the Clymer manual I have contains an error. So do the directions in the factory manual. Here is how I got them in correctly. I put the valves into the correct holes which is determined by the grooves on the valves themselves. I then put the operating rod in place and installed the plate on the side of the cylinder, of course you put the seal holder on first. Put the e clip on the operating rod, collar and the outside e clip. Now here is where I found the manuals to be in error. Instead of pushing the operating rod in PULL IT ALL THE WAY OUT to the open postion. You then lift your valves slightly and turn them until the punch mark points forward. There is a small ridge on the edge of the cylinder in front of each valve , they look like sprue marks in the casting. If you can not see the marks just point your punch marks forward and you will have it right. If you shine a small flashlight into the exhaust port you should be able to see liht in the cylinder through the small exhaust "eyebrow ports" When you push the rod in the ports will close. Hope this helps. Ben

mcoker · Apr 14, 2003

Thanks guys, I will try this. Just to make sure I've got it right, when you say point the punch marks "forward", you mean like, away from the cylinder wall?

MX175 · Apr 14, 2003

hasBen, if you are correct, I just reset my valves wrong! And that is the way it was when I got the bike. Please provide clarification.

At low rpms, "I think" the KIPS valves should be closed and so exhaust cannot go from the cylinder through the "eyebrow ports" to the exhaust pipe. The port on the right is closed off and the port on the left is open to the resonator on the left side of the cylinder. The actuating rod is positioned to the left.

At high rpms, the actuating arm is moved to the right which opens the eyebrow ports to the exhaust pipe. Is this correct?

hasBen · Apr 15, 2003

mcoker Yes, away from the cylinder wall is correct. MX175 your explanation is 100% spot on. That is how everything should function. I am curious, did you set yours up using the information in the manual? The manuals say the punch marks should line up with the marks on the cylinder when the operating rod is pushed all the way in(closed). If I put the valves that way in our bike they were WAY out of whack. I finally set them using common sense and a little theory and all was good. Once I had the valves operating as you described I looked to see where the punch marks were. With the operating rod pushed in the punch marks did not line up with the cylinder marks. I pulled the operating rod all the way OUT and noticed the punch marks were lined up perfectly with the marks on the cylinder. I assumed the manuals were in error but now I wonder if the punch marks on my valves are mis-located. Please let me know if your punch marks lined up with the cylinder marks when the operating rod is in or out. Thanks, Ben

MX175 · Apr 15, 2003

I only have punch marks on the valves, nothing on the cylinder. When the actuating rod is toward the left (low rpm), the punch mark on the valve is forward. Thanks for getting back.

hasBen · Apr 16, 2003

mcoker
I hope I did not confuse matters for you. Listen to MX175's advice. If things still look out of whack check to see if your valves are punch marked incorrectly like mine were.
MX175
Thanks for clearing that up for me. It seems I owe the Clymer and Kawasaki manual people an apology, they got it right. I will mention the mis-marked valves to the new owner of our '86 KDX200. I will be listing many new spare parts we have in the classifieds section in the next couple of days. I will also list the rear wheel and rear disc brake system I had worked out for my son as he found the original drum brake left something to be desired when he raced the bike in hare scrambles and motocross last year. Likewise the DG exhaust system. As for the marks on the cylinder... both our original cylinder and our new spare have slight raised "lips or ledges" cast into the cylinder body that run verticaly up from the top cylinder fin to the machined top deck of the cylinder. They are located in the center of the hole for the valves on the forward face of the cylinder casting. Thanks again for the info Mark.
Ben

mcoker · Apr 16, 2003

Just for peace of mind, I took a flashlight and shined it into the exhaust header in the cylinder... and when the rod that connects to the exhaust valves (the long one with 2 sets of teeth) is pushed in, I could see light in both of the "eyebrows" in the cylinder. And when the rod is pulled out, it closes and I can't see any light shining through the "eyebrows". Is this the correct positioning for the exhaust valves?

mcoker · Apr 16, 2003

What I described above is different from this diagram I found online

<a href="http://www.geocities.com/a57ngel/moto/kips3.html">Click here to see the diagram</a>

In the diagram, the punch mark on the left valve is pointing forward and the right valve is pointing left. The way I did it was with both valves facing forward. Which is correct? Or are they both wrong?

mcoker · Apr 16, 2003

After re-reading you guys' posts, I arranged the valves so that...
When the rod is pushed in, the valves close the "eyebrow" ports to the exhaust header, but the resonator-side is open so that exhaust from that eyebrow port goes to the resonator.
When the rod is pulled out, the resonator-side eyebrow port is closed to the resonator and open to the exhaust header on both sides. So I can shine a flashlight into the exhaust header when the rod is pulled out, and I can see light in both eyebrow ports from inside the cylinder.
Is that how it should be?

MX175 · Apr 17, 2003

mcoker,
That is the way mine is set up. The eyebrow ports are only open to the exhaust pipe at high rpm (KIPS rod moved to the right).

exhaust valve positioning

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