4 cylinders, 0 compression, help!!

[SPARKSS]

I concur that the carbs do NOT need to be open to "create" compression. Engines have developed good compression from allowed idle air for decades!

Now to your problem......The one thing I keyed on was that you mentioned that air was puffing out of your carbs during cranking. This suggests either cam timing (which you say you've checked.......just keep this in mind) OR that it's possible the engine is cranking backwards! Check THAT just for badness when you're looking things over!

[Billy Ricks]

Cams may be off by a matter of teeth rather than 180 out. He did say there is evidence the valves hit the pistons. PO may have used the wrong marks on the rotor to drop the cams in.

[Nessism]

Cams may be off by a matter of teeth rather than 180 out. He did say there is evidence the valves hit the pistons. PO may have used the wrong marks on the rotor to drop the cams in.

Easy way to check for bent valves is to check the valve clearances - bent valves will have a large clearance. Been there done that...

[smagnusen]

Update: Success! -at least mostly. After reassembling the motor and adjusting the timing a cold dry crank gave me over 120 pounds on the first cylinder. That felt good. 3 and 4 show the same but number 2 is only at 25 or so pounds.

This brings me to another question. Strangely I could not get the timing tick on the exhaust cam exactly where it should be at tdc. Clymer shows the #1 tick to be exactly pointing to the gasket surface. It clearly wanted to be either above or below it. Any thoughts? I did notice that the clymer manual stated that the tdc mark was to the "left of the T" mark, and on my bike it is to the right. Are these few degrees out enough to effect the valve timing?

[oldschoolorange]

if the engine has kissed the valves there is a good chance one of them is bent, A real quick way to check for a valve seating if you do not have a vacume pump is to tip the head over so the valves are straight up and them pour varsol onto the valves. The varsol will pool and no leaks will be visible if the valves are seating properly

[Nessism]

if the engine has kissed the valves there is a good chance one of them is bent, A real quick way to check for a valve seating if you do not have a vacume pump is to tip the head over so the valves are straight up and them pour varsol onto the valves. The varsol will pool and no leaks will be visible if the valves are seating properly

Easier way is to check valve clearances. A bent valve will not close all the way thus the clearance will be excessive.

[smagnusen]

With the head upside down on a bench I put pool of carb cleaner in each valve area and the valves seemed to hold it pretty well. Valve clearances were nil but I did change the shims down a size on reassembly. Think there was some clearance but will check them again.

[oldschoolorange]

Easier way is to check valve clearances. A bent valve will not close all the way thus the clearance will be excessive.

Ahh that works if the valve is bent however if it is just not seating properly due to a small amount of carbon buildup it could be difficult to detect looking at clearances.