My No-Fuel Mystery

[Dr. Frankenstein]

Okay, so - I'm working on another CA77 - my 1962 -(not the one I'm having the acceleration problem with, that's a '64)...

With this one, I tore the engine Completely down - opened it up, emptied it out and rebuilt it with a new gasket set; new seals; I had the valve seats and valves professionally redone; it/they pulled about 150 lbs pressure when my tech guy tested them at the shop...

I rebuilt the engine; rebuilt the switch (See "Switch Dissection' in here) ...put it all back together again , and here's what's happening:

In a nutshell, I have no fuel getting to the carb. The carb is Thoroughly clean - manually and with an ultrasonic cleaner...the floats are at 26.5 mm from the carb mounting gasket; the jets are 35-Slow, 120 Main, and 20 for the needle seat. Passages are clear.


The bike cranks Great; I have a nice fat spark on both plugs; but it just will not suck fuel. I can put my hand over the intake and it sucks it in, but I tried shooting starting fluid into the carb - nothing. And Interestingly, I don't seem to smell it on the plugs when I take them out - but the valves are opening - I see them!

I tried taking the carb OFF and shooting starting fluid directly into the engine. Nothing. Again, I HAVE spark!

I adjusted the valves - again - to 0.10. Nothing.

The timing is, or appears to be, right on...points gap set to .35mm...

The battery is fully charged. I adjusted the valve clearance Again - nothing.

I tightened down the head bolts a bit more; nothing.

I thought it might be a weak/flattened carb o-ring - didn't have another, so I made a gasket to put between the carb body and the bakelite piece - and Yes, I cut out the cut-out part. Nothing.

I'm now pulling 80/85 lbs in each cylinder - low, I know. *I think I have a compression problem, but WHERE?? The head tested at just about 150lbs! So WHERE am I losing compression? New top-end gaskets, new low-end gaskets, new seals, professionally done valves and valve seats...


As Washington said at Valley Forge: "WTF"??

[Geoff Hastings]

If it's not firing even with fuel or easy start directly into the inlet and you have a healthy spark then the valve timing must be well out. I'd do another compression test just to make sure the valves have not come into contact with the Pistons. If it's still ok then I'd recheck the valve timing, if it's not ok then you might have bent a valve.