carb? valves? What?

[claybear]

So I just did a ring job on my 1980 xs over the weekend, it had a blown piston in one cylinder so I had to replace that. After getting it all back together it didn't run right, went through the carbs, (which still friggin leak). It has the old vaccum petcock, (which also leaks). She's pissing out the carb on the left,(into the airbox). So obviously there's still work to be done there. But she fires, cold, 1st kick! However, I'm having troubles, she blows white smoke when I'm revving. Only out of the left, (same cylinder I had to replace the piston in, same one that has the pissing carb). So what my question is, will the carb be the problem that's causing it to smoke? Or do you guys think it's something more serious, like a screwed up stagger on my rings, bad valve guide or seal, etc.
Also the pin that holds the floats in is stuck in there good, any ideas on how to get them out without just beating the shit outa them? Would a sticking float cause all of these problems?
I know that I have to fix the t fitting in between the carbs since I don't think that's sealing, but I know the floats must be stuck on that carb at least since the airbox is wet.

 

[remmy1101]

more then likely the sticking float is the cause of all the problems your describing. I use a small punch and tap it with a pair of pliers to get those pins out.
I would clean the pin with sand paper really well and also try to clean the inside of the hole on the float that it goes in to with a small pipe cleaner if you have one. you have to make sure these float move freely and i mean test it with your finger with the carbs sitting upright hitting the float over and over again to make sure it does not hang up.
I bet if you do this and adjust the float height correctly all your problems will disappear.

 

[yamaman]

why did the piston burn up in the first place? Make sure your ATU is working properly!

 

[claybear]

I honestly have no clue why the piston blew up. It had pretty much the whole top missing when I tore it down. How do I check the ATU to know if it's working properly? It's the stock non adjustable ignition, and the book doesn't give much detail on that. I was thinking that it was carb issues that made her go, the jet on the top of the carbs, (air mixture I think I read somewhere) was turned all the way in, while the other cylinder was turned all the way out. I set them both at about 3.5 turns now.

 

[5twins]

You don't have an ATU if you've still got the stock electronic ignition. Your advance is controlled electronically.

 

[yamaman]

Sorry, just re read the 1st post & see you said it's a '80, so no ATU.

 

[jay760]

Have you checked the inlet manifolds to see if they're leeking? quite often the cause of a holed piston.

 

[claybear]

I actually think it's from the line that runs to the gas tank from the manifold, I now when I ran it the other day it was smoking from there. I tried plugging it to see if that helped with the smoking problem but it didn't. I'm gonna try going through the carbs this weekend though, and hopefully that will help some. I did pull the plug and look at it, doesn't look like it's oil fouled, it's still dry, but it is sooty.

 

[rockdr]

sounds like need to get the carbs under control for sure. Gas washing the oil off tight pistons, too hot making white smoke. Fix the carbs.