Starting new to me kz650 after 2 year sleep

Ok, I know there is much to be done, but I wanted to hear it run. Tank was removed I plumbed it using "test tank".
It kind of started on ester, but I wanted to see if it's going to run on gas.

It would try to "catch" on one cylinder but wouldn't run.

Plugs would foul. #4 stays dry.

Next thing I tried - checked compression today on completely cold engine. Dry numbers on cold:
145 130 135 150 good, but 130 vs 150?

Checked with little oil in spark plug hole:
225 225 205 220
Better, but cyl 3 not consistent?

Any conclusions from those numbers?

Next, I plugged vacuum hole (not supply hole) and it started on choke. What is a function of this vacuum line? Should it be plugged when run without stock petcock? Or maybe it started after oil in cylinders (better compression). But it didn't right away and I thought plugs would be completely done with oil, but plugged vacuum and it started!

It ran with choke but would die when choke removed. Once warmed up it would rev and even run without choke a little but not good.

Checked headers temps with IR termometer. Cyc 1-3 - 300C, Cyl4 - 80c.
Spark was on all cylinders.

My conclusion that it should run once I clean carbs. Sounds right?

First thing I do after buying a 40 year old bike is rebuild the carbs and check the valve adjustment. if the bike has points check and clean/adjust those too, and change the spark plugs. Check the fuel tank for debris and get rid of the old gas if there is any. It's time well spent and will avoid many problems and much head scratching as to what's wrong. Only after all this is done do I bother trying to start the bike.

If it were mine, I would check my pressure gauge. That second set of numbers is really high.

You should definitely clean the carbs. Also check valve clearance with the engine cold.

hardrockminer wrote: If it were mine, I would check my pressure gauge. That second set of numbers is really high.

I was really surprised too. Those are Harbor freight gauges so they might be off. But consistency is there, so even if they off, do those variations bad?

Nessism wrote: First thing I do after buying a 40 year old bike is rebuild the carbs and check the valve adjustment. if the bike has points check and clean/adjust those too, and change the spark plugs. Check the fuel tank for debris and get rid of the old gas if there is any. It's time well spent and will avoid many problems and much head scratching as to what's wrong. Only after all this is done do I bother trying to start the bike.

Still waiting on my factory manual and sandblaster parts to get soda blasting going.
I know carbs need to be done and of course I will do tune up but for now I just wanted to try and see if it runs at all.

Tank will need clean and I still wait for petcock parts, but I bought this "temp tank" and will be using it for now until ready to go. So much more convenient not having tank on a bike.

For valve check, what gaskets need to be replaced? Any other consumables? I even have what I think factory feeler gauge in stock tool set

I also read somewhere about chain tensioner adjustment, is it good idea "while there"?

You got me curious. The only way for me to check gauge is to hook up to my air line in garage. So, I set pressure regulator to 150 and hook up gauge I used for compression test. If anything, it "lies" other way.

Just guessing here but you may have huge carbon buildup in the combustion chambers. That would elevate the pressure. If you have a small camera you could pull a plug and take a peek.

Regarding the valve lash check, you may need to replace your valve cover gasket if you tear it when you take the cover off.

The compression numbers on the second test will be high because you added oil into the cylinder effectively reducing the combustion chamber and raising the ratio. Considering all the compression is above 130 I would give it the ol "Italian tune-up" and see if it has any problems running.

DoctoRot wrote: The compression numbers on the second test will be high because you added oil into the cylinder effectively reducing the combustion chamber and raising the ratio. Considering all the compression is above 130 I would give it the ol "Italian tune-up" and see if it has any problems running.

Exactly! Ed