KZ 1100 Won't start... except rarely

In my experience, the symptoms described are not valve clearance related. Usually with valves, the first symptom is that the bike stalls right after a really hot run. It just dies when you come to a stop. 5 seconds later it will start and maybe run rough for a few seconds then will run fine like nothing happened. That's because the valve only stretches past the clearance limit during a hot run, but not enough to affect the running, but if you go to idle quickly, it will stall. Then the valve will quickly shrink back down. A compression test won't show a problem since the motor will cool down way before you can do the test.

The reason I suspect something else is that you had a short run with no problem, even with the engine warm it started. If it was the valves, and they were bad enough, the warm start should have been more difficult than a cold start.

Even though external engine parts seem to overheat at idle on a hot day, the internals heat up more when going at highway speeds.

If your valves are out of speck, though, you definitely need to take care of that first before anything else.

I would suspect a connector under the tank, especially since you've had it off. That connector is notorious.

Yeah, I'm still a bit iffy on exactly how valve wear works and how my valves could be so far out of adjustment on the tight side rather than having increasing clearance. But now that I know they are all (except two) out of spec, I need to finish this job. I'm waiting on the shim replacement tool from Z1, and then I can pull and inspect the shims (one at a time, I know) to see what I'm working with. Then I'll have to wait on those to come in as well before I can put her back together.

I wondered about that under-tank connector between the fuel tank and the instrument cluster. If that is not connected properly, can that cause the bike not to start, though? I'll definitely clean it up and pay special attention to hooking it up. It's in such a fun spot, under the tank. I've had to be creative with firewood to hold the tank up while i work.

Look inside the headlight housing too as many connectors there can get corrosion. I use a very good brand of cleaner/preservative made by Caig Labs in San Diego.

The website is www.deoxit.com and it can be purchased at Radio Shack stores in the U.S. and I'd imagine at most electronic supply stores elsewhere.

I had some issues a while back, the bike would cut off but would refire, it then got to the point of having to turn the key on and off,, the wires on back of the key switch came loose, replaced the key switch to solve it.

sure does sound like a loose connection problem,and those are the most fun to chase down

Okay, as the information keeps coming in, I'm assembling a better picture in my mind of what's going on. But I may have just made the problem far worse.

Short version: got the Motion Pro tool, which takes some learning, but I got all eight shims out and recorded their sizes, one at a time.

Problem: On my third one, which happened to be cylinder #1, exhaust, I got the shim partway out when the wedge tool slipped, trapping the shim between the bucket and the cam lobe. I managed to use the pry tool to gain enough clearance to get the wedge back in place and slip the shim back into the bucket.

To rotate the crankshaft with a wrench, you have to reach over the bike, since the #1 cylinder is on the far left. I started turning the crank to go around 270 degrees to get back into position to remove the shim, but as I looked over at the valve I saw that the shim had slipped back out of the bucket and once again was trapped. The cam lobe was just about horizontal at this point. I managed to back off the crank just far enough to release the shim, and eventually got it out without further mishap.

My question: is it likely that I bent the valve in this operation?

Additional evidence: A couple of replies suggested that my problem might be electrical rather than having anything to do with the valve clearances, so I decided to test that theory. After I got the shim sizes recorded so I could order thinner ones, I cleaned and checked all the connectors and wiring, especially under the tank. Then I put everything back together carefully.

Wouldn't you know, the bike fired up (and this morning even more readily) --- but only on three cylinders. The cylinder that's not firing is... #1. I think it's getting spark, from the fact that the plug is slightly warm. So, is the exhaust valve bent, or is there something else I could have done that's causing this problem?

I added an exhaust valve to my Z1 order for the new shims, but of course that will mean yet another learning experience: tearing the motor down to get at the valves. Suggestions / thoughts most welcome. RB

If it's bent, then a compression test will let you know right away. I'd try that first.

rbdancer, I scanned thru this topic, and did not see where you reported back on ohming out the pickup coils.
Also , it is important and easy to determine if it is getting spark, and if it is not, then there is no need to worry about the valve clearances at this point.
If it is getting spark, then spray some carb cleaner, or starting fluid into the carb intakes, and see if it runs.
On my bike, it has to be at idle, or very close to start. If I hold my throttle open , it will not start.
To check for spark, use a spare spark plug resting on the engine, or hold a screwdriver GENTLY stuck into the plug wire, and hold the screwdriver about a 1/4" from the engine while cranking it.

Yep, I forgot to mention that I did check the pickup coils and they are right in the center of their range. Also, I am getting a spark at the plug, so electricals are now working properly.

This bike likes to start with full choke and no throttle, then gentle application of throttle while cranking. Go figure. Now it's starting great --- except for that cylinder #1.

Now I'm off to look up compression testing.

Rbdancer, shadetree that I am, sometimes my methods get straight to the problem. It is sometimes possible for mechanics to overload the goal with expertise.
If you want to check your valves, cyl leakage, etc, get a blowgun that has a rubber tip that will seal to the spark plug holes. Regulate the air pressure to it to a safe 30-50 psi( pick a pressure out of a hookers hat if you want. I just would avoid high pressures)
Remove the alternator cover on the left side. On my bike it is half a dozen 5 mm allen bolts. Apply pressure to each cyl while slowly turning the crankshaft and listen carefully for air leakage. At some point , every cyl should get very quiet, and they should all sound the same when it is their turn for both valves to be closed. I would remove the air filter to make it easier to hear air escaping past the intake valves. For the exhaust, you can just listen to the exhaust pipe.
For an even quicker test, have an assistant push the bike while it is in a higher gear to rotate the motor, instead of having to pull the alternator cover.
Report back here, corporal, and there will be lots of Monday morning QBs like myself to walk you thru the next step......David

if you do this test, remove the oil filler cap so you can listen and feel air escaping past the piston rings.

Yes check you compression, do you know how to do a leak down test? Put the cylinder to be tested at TDC firing position and supply compressed air to the plug hole and listen to where it escapes. You can buy a cheap 1 at Harbor Freight Tools.
Also have you ever sync those carbs? There are many posts about how to do it and how to make a cheap sync tool < $6.
Make sure that compression is even, no vacuum leaks and carbs are clean, ignition is good, and set the carb balance so each cylinder is running the same vacuum, "Sync"

Procedure on the right...Maybe will give you some additional insight....