1980 KZ1300 - Hen's Teeth Do Exist

[robin1731]

[quote="Lucien Harpress"]snip..........
I'm going to check compression this week. quote]

That will tell part of the story. A leakdown will tell you more. Still sounds like it could be a valve not sealing.

[Lucien Harpress]

Yeah, it's something I should've done a long time ago. Benefits of working on 4 bikes at once instead of one at a time....

And, of course it HAD to be one of the inner cylinders. Where you can't get the plugs out without taking the gas tank off...

[Barney T Weasel]

Carbs are dead easy on these.

[Lucien Harpress]

Whelp, got the compression tester home. I'm taking it easy for a bit (started running again, and APPARENTLY I'm extremely out of shape. Who knew?) while the battery charges. I should get some numbers here by the end of the day. Stay tuned.....

EDIT: Tried popping in the compression tester to get me some numbers. The good news? UNlike my Goldwings, it actually has the correct size adapter for the spark plug hole. The bad news? I'm not sure how to change them, and I don't feel like breaking one of my dad's tools finding out. So, we wait until he gets home.

However, I did do the old "finger in the spark plug hole" trick, and all cylinders (including the problem one) have some kind of compression. No telling if it's low or not, though.....

I did notice that when I pulled plug 3, it looked like it was covered in oil. I noticed that side smokes really bad when I started it up before, and it looks like oil smoke. Could be crud-soaked gas too, but I'm not sure... anyway, more info when I can actually get the tester working.

[Lucien Harpress]

Finally got the compression test done. The results are... not really surprising.

Cylinder 1: 125
Cylinder 2: 150
Cylinder 3: 100
Cylinder 4: 150
Cylinder 5: 125
Cylinder 6: 150

So yeah. Low compression on cylinder 3 looks like my problem. On the plus side, I did squirt a bit of oil into the bore to check the rings, and nothing changed, so (knock on wood) rings should be fine.

Next up is a leak-down test. I'll have to check O-riley's, see if they have a rubber tip for my air compressor, but I'm fairly certain it's valve-related. I'm just hoping that a setting is off.

The oil smoke out that side of the exhaust still concerns me. As I said before, when I pulled the plug it was coated in either gas or oil. I'm having nightmare visions of worn valve guides, and how much money it would take to fix that..... Still. [deep breath] Simple things first.

[robin1731]

The good news if it is a valve guide. They used the same guide on 178 different models. So getting them will be easy. But if you change guides you have to get a valve job done. The machine shop is where the money is spent. Removing and installing guides. Reaming guides to fit. Cut the seats. Grind the valves. Then new seals and put it all back together. Easy if you have the tools for it.

[Terry in Australia]

If the plug is oily and the compression is down, I'm guessing it's a burned exhaust valve. Pretty common on DOHC engines of the era. Cheers, Terry.

[Lucien Harpress]

Should the head have to come off, the worst part (apart from screwing EVERYTHING up like I did on my Gold wing) will be finding gaskets for it. Aftermarket kits are available, but after my GL1000 debacle I'm a bit gun shy of using anything other than OEM.

On the plus side, I should be able to check all the cam chain tensioner stuff while I'm in there. Apparently that whole mechanism is a weak part of the design. We shall see.

[robin1731]

I use Vesrah gaskets on all of my KZ builds that are not race engines. No problems at all.

[Lucien Harpress]

Tough to say what's out there. There's an entire engine gasket set for under $150, but it's made by Emgo, which makes me VERY leery. The other option was a " Vesrah equivalent". Still... eh.

My other option is to just try to piece together what I need as close to OEM as possible. Already have a valve cover gasket coming, Vesrah valve seals are easy to find, and I can wait until someone is selling another OEM head gasket. Not sure what I'm going to need when I comes to the radiator, but I think the top connector comes straight off the head.... Again, tough to say without a leak-down test and with no clue about valve clearances.

[robin1731]

snip......... with no clue about valve clearances.

I guess I figured you had checked the valve clearance. This should have ben one of the first things. Just like any new to you bike this old. The good thing, again, is that bikes uses the same shims that a 900/1000 does. If you don't have access to shims I can help you out there. But you'll need to be sure what size's you'll need. Shims are not cheap.

[Lucien Harpress]

Yeah, nothing's been off this bike except the gas tank and carburetors. I've got a valve cover gasket coming. I figure I'll wait for that to show up before I pull the cover. Gives me time to read up on the manual to figure the right way to check these things. I've got the basic idea, but it's all about the specifics. It's also got a table that shows what shim to use to correct each valve clearance discrepancy, so I should be pretty good there. It's my first time dealing with this type of valve setup, so this should be fun.

[robin1731]

If you do need to change valves you'll need a valve removal tool to make it easier. They be found on ebay or at Z1. The manual probably shows a pic of it. The table works but you have to know what size shim the valve has now. They are marked when new but depending on how they were installed the numbers may be worn off.

And remember, it is better to have the lash a little on the loose side rather than too tight. If book calls for .004" then .005" is ok. The shims are in .002" increments.

[Terry in Australia]

Do KZ1300's have "Shim under bucket" arrangements, or the older "Shim over bucket" setup? Cheers, Terry.

[Lucien Harpress]

Shim over bucket. Thank God.