'79 not firing

[alehman]

So I've had my '79 for about two months now and I've learned a huge amount. I've settled my electrical issues and have spark in all four cylinders, cleaned and rebuilt the carbs, but still have some issues I was hoping you guys could help me out with.

Mostly, it's not firing. When I finally got the battery charged and turned it over, rusty smoke came out of the exhaust, followed shortly by white smoke, and then I got a backfire or two. Not starting though. Now when I try to start it, I don't even get a backfire. Also, the rust is probably from junk stuck in the exhaust, not from the cylinders. After rebuilding the carbs, everything went together fine except I forgot default settings--- What should the default settings for the pilot screws and idle screw be? I don't know if that would affect starting.

I have some strange issues. When I first tried to fire, I didn't have the carb boots fully tightened, and at one point I heard a loud pop and saw that the carbs had been dislodged from said boots, with a little white smoke rising up. I'm guessing there shouldn't be pressure on the carbs, so I'm trying to figure that out. Is it possible for my valve timing to be off?

Another curious thing about the carbs is that the drain valves are decently leaky, and the #1 carb bowl fills up and doesn't stop filling, because it shoots fuel out the overflow channel after a little bit. I've checked the floats, they're all fine, I've installed new needle valves in all the bowls, and I've seated them all with a q-tip and carb cleaner. No dice still.

I know there are basic tune-ups I need to perform on the engine, which I haven't done yet (valve clearances, cam chain tensioning, checking spark timing). Would any of those significantly affect starting the bike, and are there any other things I should do? Sorry to be so long-winded, but you guys are my best bet for these issues.

[seestheday]

By default settings, do you mean the air/fuel mixture screws?

The default setting should be around 2.5-3.5 turns out for each of the 4 screws.
See here: http://honda-cb750-s.456789.n3.nabble.com/DOHC-carb-cleaning-procedure-td867809.html

That said, if you have a non stock muffler, jets or pods, you'll have to play with the air/fuel screws to get them right.

Did you bench sync the carbs?  It should still fire if they're off, but it'll run very rough.

Are you getting gas to the cylinders?  If you pull your plugs after you try to get it to start do they come out wet and smelling of gas?

Have you tried to start it with starter fluid?

[TOOLS1]

It sounds like, your timing is off. Either ignition, or valve, or both. As, for the carbs. Are your floats bad? Put them in a container of gas, and see if they float. Also one more thing, are they in right side up? I have seen them installed upside down.
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[alehman]

ah, I might have the air/fuel screws a little too off. I had them at 2 turns out. Carbs are not yet synced. I am pretty sure fuel delivery is good. I've pulled out plugs numerous times and they were frequently wet with gas. I'll double check on that. I have not tried starter fluid either.

[alehman]

also, TOOLS, I did test the floats, but I tested them in water. I'll try again with gas. I'm positive, however, that they're installed right side up because I caught myself installing one upside down and made sure that I didn't muck up the others. How do I adjust valve timing?

[TOOLS1]

That, you are going to have to look, for in the manual. You can download it, for free from the homepage here. Just look in the manual section.
TOOLS