Valve adjustment question...

I was measuring my valve clearances last night on my 1977 KZ1000, and the results puzzled me. I bought this bike over the spring, and have put about 2500 miles on it since then. Everyone has told me to check & adjust the valves if necessary every 4-5 thousand miles. I am guessing that they weren't adjusted anytime soon before I bought the bike because the previous owner did not seem to be real dilligent on maintanence. I checked the clearances and none were less than .08 mm, most were right at .10 mm, and two of the exhaust valves were actually just a touch over .10.
I don't understand how that could be and I'm wondering if I'm doing something wrong. I checked them all by lining up the marks on the cam sprockets with the top of the head, so that the top of the cam lobes faced either up or on an angle AWAY from the valve itself. Then I'd rotate the crank a full turn and measure the other pair. Is this correct, or is there a better way?

Sounds like you are following the correct procedure for checking. How much do you know about the PO? Is he the original owner? If not then how long did he have the bike? A lot of stuff can happen in 33 years. I doubt that those are the original shims since some are a little over the original high spec of 0.1mm. I believe that the spec was later revised to 0.05 - 0.15 mm. I would just be happy and run it as is. Are you experiencing any problems?

Agreed. Sounds like everything is fine.

.05 - .15 mm is good.

Are you pressing the feeler guage flat against the shim first, then trying to slide it between? If so, then I'd say you're good to go. Button up and ride

GL.

I don't really know too much about the previous owner, except that everything other maintanence item on the bike was not maintained very well. I went after the valves because I've been fouling up plugs. The carbs were just redone, jetted up one size, I run a MAC 4-1, Dyna coils, ignition and wires. The bike runs great with clean plugs, idles nicely when warm. I use the choke extremely sparingly, and don't do a lot of idling. But the plugs are so sooty after the last 1000 miles I put on, that it started to run pretty crappy. I'm thinking that I should be going after my electrical system to make sure I'm getting enough voltage?

Did you recently fuel up at an different location than normal? Or is the 1000 mi plug fouling consistent? I think that it would be worth your time to check the voltage at the coils.

it is consistently sooting up plugs. not really any signs of oil either. I just dont see how it could be running so rich with only one size up jets and running a 4-1...thats whats making me think my spark isnt hot enough. what is the voltage at the coils supposed to be?

It should be 14-14.5v at 4000rpm. If its less then I would check the battery. If the two are different, then inspect the wiring for corroded connectors, cut insulation, frayed wires, loose connections. If they are the same but lower than the 14v then I would suspect the charging system is at fault.

A basic spark quality check is by visual inspection of spark on plug tips while spinning over the engine with plugs removed and their bases held grounded against the engine head.

Look for fat blue sparks.

Would also assure fuel levels inside float bowls are correct (especially not too high) by performing the clear tube test.

Too high fuel level can cause overly rich mixture even with otherwise perfect carbs, perfect compression and valve clearances, and perfect properly timed spark.

Good Fortune!

Could also experiment by leaning the carb pilot circuits, say 1/2 turn on each adjuster screw.

Stock carb has bottom-located pilot mixture adjusting screw on engine side of carb. The screw turns in clockwise to get leaner mixture. And would turn out counter-clockwise to get richer mixture.

Where carb has side-located pilot air adjuster screw on airbox side of carb, turn in clockwise to go richer (allows less air) and turn counter-clockwise to go leaner (allows more air).

Good Fortune!

[Click on image to enlarge view.]

if you went one step richer, from what,, possible someone had already done that and you just went farter? what size did you install?

For reference, stock VM26SS Mikuni carbs have 107.5R main jets and 17.5 pilot jets (per FSM).

Good Fortune!

BSKZ650 wrote:

if you went one step richer, from what,, possible someone had already done that and you just went farter? what size did you install?

This is a very good point. I assumed that you knew that the jetting was correct. Silly me. It could also be worth a look in those float bowls to see what size jets are really in there if you don't already know. I think that MAC advertises that you don't need to re-jet for their 4 into 1. It is possible that you are just a little rich on those jets.