Major cam timing screw up

So I am working on a 79 KZ650. Everything was going great. Got a fresh hone, valve seals, valve grind, new gaskets, all the good stuff.

I went to start it up for the first time and I got nothing. Everything sounded like it was spinning good. But not even a sputter. Checked the compression and got 0. nada. Ziltch. Double checked the cam timing and noticed it was on the 2.3 mark and NOT the 1.4 mark. So I retimed the cams, double checked the valve clearance for good measure and put it back together. This time it will start up but it runs poorly. it won't stay idling and it backfires. Sometimes out of the exhaust and sometimes out of the carbs. I bent valves didn't I? I had read somewhere that this was not an interference motor. But I am starting to think I screwed the pooch on this one.

Looks like you have to pull the head again. A bend valve(s) is possible.
After a correct cam timing you have to turn the engine by hand slowly to feel any resistance by valve / piston collision.
One turn with the starter motor and all your work is scrap metal if the timing don´t match.
Removing the spark plugs and look into the cylinder #1 to verify that the piston don´t hit the valve when turning the engine.

Michael

Bent valves should show up with approx double the valve clearance that you had before and very low to 0 on compression.

Valve clearance all checked out after I retimed everything. I checked #4 compression real quick on a stone cold motor and got 120 after a few short cranks I am about to leave the office. I am going to check compression on all 4 and do a poor mans leak down with just some air compression and my ears. We will see.......

Check the piston dome valve pockets for punch marks by the valves disk through the spark plug hole.

KZB2 650 wrote: Bent valves should show up with approx double the valve clearance that you had before and very low to 0 on compression.

I would be obvious. When I did that I could see light under the cams. If it happened now would be the time for a three angle valve grind, valves, etc. That's what I did in 87. This time around all I had to do was new valves lap them and seals.
Steve

Something is not right.

Compression is 90 90 90 90 on a stone cold motor. Quick and dirty leak down test went well on 1 3 and 4. But get this. When I fill 2 will compressed air it comes out of the spark plug hole for 1. That's super not good. What on earth could be causing that?


Edit: just redid the compression test with a few drops of oil and got 130 across the board.

Edit 2: if I put the 2-3 timing mark on "f" instead of "t" then #2 does great on the cheapo leak down test.

If my logic is right the leak down test air on #2 ( light bend ex valve ) flows back over exhaust system through the open #1 exhaust valve back into #1 combustion camber.
I could be wrong but nothing else should effect this,,except a blown head gasket.

The valve clearances will tell the story if the valves are bent. No way to bend a valve and have the clearance same as before.

If you initially set the timing on the 2-3 marks this puts the timing 180 degrees out and the pistons nowhere near the valves so you have no chance of bending any valve.

Yeah, I don't think anything is bent. I did all of my valve clearance adjustments while it was set at the 2-3 mark and I only turned it by hand while making the adjustments. I never felt anything. Would I even be able to bend a valve by hand? I had the valve seats reground so the clearances were SUPER tight. But I got some smaller shims that put it right in spec.

Did you fully break down the carbs, remove all the parts, and soak all the metal parts in carb dip? Replace all the various O-rings? Verify all jets are the factory parts (unless your bike is modified)?