I think it's a vaccum line issue...

[tom203]

But which way is prime? Should the slit be horizontal or vertical?

I vote vertical,but try in both ways- still needs a vac pulse to get going even in prime.

[Steve]

Isn't the vacuum on #3 or is it different on CV carburetors?

It is different. On the VM carbs, it is inded #3. On the BS carbs it is on #2.

Forget blowing nonsense- disconnect fuel line at petcock ,get beer can to catch fuel, suck on vac line connected to petcock- fuel should flow out and stop when you stop sucking.

Just wondering why I might have to go out and buy the first beer I have every bought, just so I can dump it out to check fuel flow.

Yeah just about any container that will withstand gaoline should work.

Get a small screwdriver and try prime setting to encourage fuel flow to assure the bowls are filled.

Keep in mind that the "dreaded '80 petock" works a bit differently than most.

On all the others, you simply turn the petcock lever to the PRIme position and gas flows. On the "dreaded '80 petcock", you have to turn the petcock to PRIme (slot will be vertical) AND apply a 'puff' of vacuum. After that, fuel will flow until the petcock is turned to the RUN position or the supply of gas is exhausted. That means that if you are trying to prime the carbs after the bike sits for a while, you turn the petcock to PRIme, bump the starter so the engine spins a couple turns (to ensure that #2 has done its intake cycle at least once), then turn the key off while the carbs fill.

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[tom203]

Just wondering why I might have to go out and buy the first beer I have every bought, just so I can dump it out to check fuel flow.

.

Buy one? all parking garages have beer cans free for taking-

[Dogma]

If the petcock is original, it probably needs replaced. On the prime setting you shouldn't be able to suck air through it. After the valve opens, there should be no more air flow (on prime). Anything else is a faulty '80 petcock that won't stay open long enough to feed the bike. Also, the faulty part can't be fixed or rebuilt. It's not a cleaning issue, it's the little plastic valve thing you turn with a screwdriver. Maybe some chemist knows how to make it swell up and seal again.

[Guest]

I have an 80 tank on my bike. The little screw slot is not very accurate on the valve. Plan on pulling the fuel line when you have turned the slot back to the horizontal position for vacuum only operation. You may still have to tweak it a little bit to stop the fuel flow. It can look perfectly horizontal and still flow fuel. The only way to be certain it is to check it with the fuel line off so you don't end up with a crank case full of gas.

[Sojourner]

Well I made it home.

The wife dropped me off at work with my battery charger. Took the battery out of the bike, walked into the office, and proceeded to kill time from 8:30 till 10:30 while it charged. Read the above posts, packed up, put the battery back in the bike, turned the selector to prime, and bumped the starter. It didn't even hesitate; fired right up like nobody's business. So I swung the selector off prime and rode it home. Seemed a tad hestitant at times, like it was bogging a bit. Guessing it was lack of fuel flow.

So I'll empty the tank tomorrow and poke around a bit. Beginning to think it's crud more than the petcock, maybe even bad gas? Only time will tell.

[loud et]

Glad you got the bike home , despite the troubles at least its not sitting in the parking garage.
Time to dig into her!
Let us know what you find.

[chedd]

are you sure the vent in the in the tank cap is clear?if not it will create a vacuum in the tank, just a thougt.

[Sojourner]

are you sure the vent in the in the tank cap is clear?if not it will create a vacuum in the tank, just a thougt.

Didn't even know there was one! Where is it and how do I check it?

[Guest]

Most caps (all?) vent through the keyway...

I read the tank had been cleaned & painted too - was the inside of the tank coated by any chance? There's a small hole at the bottom of the filler neck that vents the tank to the neck, sometimes that little hole gets covered over with tank sealant (e.g., POR-15). check to make sure its clear.