TOPIC:

I have checked the archives and they really don't address the specific questions I have. Perhaps someone can assisted me...

I have a technical question on the head on a Kz1000A1. The motor has 23,000 miles on it and has low compression (112-125) in all cylinders. I purchased a number of supplies to do a minor upper end refresh on the aforementioned bike. The further I get into the bike, the more problematic it becomes. While removing and checking the valves and valve guides for wear and fit, all were fine except the last one (ain’t that always the case). It was an exhaust valve that, although I could spin it in the guide, I had to forcibly tap out of the guide. When I tried to refit it (thinking maybe a bit of something had caused it to stick), I had to tap it w/hammer to refit it. I then noticed that the guide itself was fairly well scored internally. The valve stem proper is entirely blackened (all the other valves have a small blackened area midway on the stem).

1.Could it be that the valve guide had never been honed and that is all I need to do?

2.Do I need to replace the valve (see above description)?

3.Do I need to replace the valve guide (see #1)?

4.If I have to replace the valve guide, how do I pound it out? I am aware of the special tools but the KHI manual says pound it out and reinstall from the top of the head. Won’t this destroy the clip that holds it in place and bugger up the head?

5. If I replace the valve guide, I must do a three/angle valve seat cut, correct? Can I just lap the tar (coarse followed by fine valve compound) out of the old seat to fit the new valve, if required?

In this situation, doing the minimum necessary is the best coarse. First is to hone the guide using a 7mm hone... just a clean up to see if scratches will come out. If they don't or you end up with a sloppy fit, you will need to replace the guide. If you need to replace, consult a couple more manuals to see what general procedures are recommended. You are more likely to do damage if you do it cold I think.

If the hone works, then clean the valve. If it cleans, that is good... just install the valve and perhaps a light lapping on all the valves.

If the valve doesn't clean, replace it. If replaced, you will need to check the stem length and possibly grind the valve. For a new valve, first try lapping it and then check the seating with machinists' dye. I find using machinists' dye more informative than filling the combustion chamber with the fluid of your choice and checking for long term leakage. If lapping does the trick, it means you are about good to go. If it doesn't, the seat will need to be touched up with the final stone (of the three stones) to reclaim the surface angle. At this point, you will need to measure the stem length.

If you are interested in all new valves, I seem to recall the Dennis Kirk outlet store had bunches of them on eBay not too long ago that didn't sell. You might want to call their outlet store as they had enough on sale for quite a few "sets" of both intake and exhaust, as memory serves and the auction price was reasonable.

what you are describing is a gauled valve, cause is 1 lack of oil to the valve guide ( most of the time on the start up ) 2 is the guide was not sized right to start with.
You can polish offthe gauld marks on the valve , but most of the time the stem is damaged and will not be round, next is the guide, it will have some metal gaulded to the inside of the guide, as george says you can hone it to fit but make sure all of the metal is removed.
If this was my head I would replace both the guide and the valve, then you know it will be right

Take one of the other exhaust valves and see how it fits in that guide. If it fits and moved good, then the problem is the valve.
As is is such a procedure to change a guide, I would not do it unless absolutly necessary.

Honing a used valve guide is usually not a good idea. If it is not already worn oversize, that is what you will be doing with the hone.

Just get a new valve and fit it.

Jay