cam chain lunch

Well, looks like I didn't dodge the bullet after all, though maybe it hit a lung instead of the heart. Two of the exhaust valves (at least) are hosed (#1 and #3 cylinder valves are stuck down). There is also a little damage where the bolts chewed away at the head, but that's in a spot that shouldn't affect anything. What are the chances I can pull the head and just replace the bent valves? Guess it's time to research valve repair.

Here's the damage from the other side. The #1 and #3 valves are bent, but otherwise everything looks OK, as far as I can tell. I don't see any obvious piston damage (not really sure what to look for). So the question is, would it be easier and/or cheaper to fix these two valves or should I just find another head? This is way deeper into my bike than I've ever gone. At least it's a learning experience.

I'd try to replace the bent valves, assuming the corresponding piston crowns aren't badly damaged.

This is time to get a manual, the UK Haynes manuals are good.

To remove the valves, get a rubber sucker tool used for grinding in valves (you will need this later) and remove the lifter bucket. Then a G clamp and some metal pipe with a slot cut in, compress the springs and use a magnetic screwdriver tip or similar to remove the two tiny collets. Loosen G clamp and you can remove the valve.

Look for valve guide damage, if a good valve slided up and down then that is probably ok.

I'd remove all the valves and grind them in, replace valve guide oil seals along with the head gasket.

The cost of the gaskets and valves you could probably get another kz550 GPz550 ZR550 motor, but then you are taking a risk on that too unless you can hear it running.

I can send you a couple of valves free, but i'm in UK and i know there is some members here closer to home who could probably help you out.

Stick with it, the first time i did this job as a teenager it felt like rebuilding a Lancaster bomber, when you have done it a few times it is more like a clockwork mouse.

Your post just made my day. Thanks very much for the advice, encouragement and offer. Two new valves alone would be $100, which is indeed less than a whole used head in good shape on Ebay! I might do both - get the head and try the valve repair just for the experience (and it would be fun to have an extra head to modify).

I have good valves I can send you. Lap them in and you should be good.

baldy110 wrote: I have good valves I can send you. Lap them in and you should be good.

I can see why you've got almost 200 thank you's on this forum. Thanks very much. Man, this whole experience has been so much better with the support of this group.

I've been reading about valves and think I'll give it a shot rather than buying another head.

I'll send you a PM.

Cheers,
Mark

While at it, pull the oil pan to inspect, and remove all ingested metal fragments. :whistle:

daveo wrote: While at it, pull the oil pan to inspect, and remove all ingested metal fragments. :whistle:

I was wondering about that. I was just going to run the bike for a few minutes (assuming it gets to that point) and then change the oil and filter. I figured the filter should catch misc shavings. Think checking the pan would catch more than the filter would? It would just mean a bit of extra work and an extra oil change (since I'd still want to run the bike a bit and then change the oil and filter, but would have to drain the oil before that to remove the pan).

I would really follow Daveo's suggestion.....if you run the motor for any length of time (even a few seconds) and there are some loose metal fragments (very high likelihood) then you will most probably be re-rebuilding.......no fun but at least you will know what to do :silly:

For peace-of-mind, I'd spend the time and minimal expense. You may be surprised to find other things hiding in there. Besides, there is no better reason to do it, especially when the exhaust is off, and nothing is in the way.
I'm curious of another thing. Were you able to remove the head without disturbing the cylinder base gasket? If there is a trick to it, I haven't figured it out. Not having to pull the jugs would sure save a lot of time, and screwing around.

Tyrell Corp wrote: ...Then a G clamp and some metal pipe with a slot cut in, compress the springs and use a magnetic screwdriver tip or similar to remove the two tiny collets. Loosen G clamp and you can remove the valve....

Some examples --








Another version --




PVC --




Good Fortune!

Thanks Patton. Those are pretty ingenious.

OK, I'll drop the oil pan. Maybe there's some buried treasure in there (in the form of future damage I can prevent). The fact that the cam sprocket bolts were likely not tightened properly makes me wonder what other treats the previous owner's shoddy maintenance will produce.

I don't have any tricks to avoid disturbing the base gasket - first time I've taken off the head in any event. I was planning to replace that gasket and one upshot of this whole fiasco is I finally get to take care of a small oil leak that's been there since I got the bike. I don't really have a clue how to take off the cylinder block and put it back on properly. I've read a few threads but it's still fuzzy and I can't find any good videos about it. Maybe I'll start another thread about that, or feel free to direct me to any good resources if you know of them.