Vapor Lock?!

So I go to start my 84 yesterday, and she strains to start. I mess with the choke, give her throttle off the choke and she dies. Normally if I even get my finger close to the start button she cranks over, so this one is frustrating me. I started thinking of the carbs, maybe gunked up, flooded, etc. Just for S&Gs I open the tank and let some fresh air in; try to start her again and she runs just fine. Is this a normal hickup for these bikes? I know the tank is vented...

 

Had you been riding it? It shouldn't (or won't) vapor lock just sitting there.

 

If your float valve needles are not sealing, the gas will leak into the combustion chamber, causing hard starts. Smell your oil. If it smells like gas, replace the oil and your float valve needles.

Also check to make sure your petcock is turning off successfully. Even with a fuel pump, the gas can leak through and keep pouring gas into your carbs.

 

I'm not sure this is the same problem but I had something very similar happening to me last week. I took off my carbs for experimenting with needle settings and after putting them back I tried starting the engine and experienced exactly what you described. It struggled to start but did start eventually after I give it max choke. It died immediately after I tried opening the throttle. Letting the engine to warm up didn't help. By touching the engine block it felt like one of the cylinders was not running (it felt notably colder than the others). I decided that I did not assemble something correctly and proceeded taking the gas tank and air filter off. After I did that I decided to try starting the engine again. This time it worked just fine! I reassembled everything and it still worked! My best guess of what have happened is that one of the floats got stuck after carbs were sitting on the shelf without gas in them. After a while it became unstuck and everything went to normal.

 

I had a night hawk that the fuel cap was not venting and the bike would quit running after a few miles. Id open the tank to check gas and close it back up. Restarted and I was off for a few more miles. I was stumped but when I went to take the tank off to chage it for another I found the issue. I was draining it out of the petcock when it stopped flowing after a minute. I thought "I know I had more gas then that in there. I popped open the cap and fuel started running out again.. Thats when the light bulb went off and I realize my gas cap was plugged and not venting...... just a thought.

 

Sounds reasonable. Yes, I had been riding it, within the last 48 hours. Before this bike I had a Vulcan and it would make the sound occasionally when you opened the cap, but not this Honda. As for the petcock, does everyone turn their's off when they are done riding. I've seen it go both ways, is there something I should know with this model?