Remote gas tank - what to do with vacuum hose?

[robsGS850]

I'm tweaking my carbs so I've rigged my tank to be off the bike, petcock set to prime to feed the beast thru a long fuel line... noticed a lot of sucking sounds and even weird blue sparking coming from the carb's vacuum line (i'm using see-thru tubing), is this normal?

Do I plug the vacuum line with something to simulate the way it's normally hooked up?

Also as a side note... is the vacuum suction supposed to be constant when revved or kinda thump-thump-thump?

thanks all

[donimo]

I would say blue sparks are very alarming, don't know where the hech that would be coming from???

Plug vacuum line would be my vote, or else it is a massive vacuum leak.

It should pulse a bit at idle, but less and less with more revs

[rcp]

Yes, plug the vacuum lines (but not the vent lines). Golf tees work. So will an appropriate sized bolt it you've got no golf tees handy.

- Richard

[Big T]

Yes, plug the vacuum lines (but not the vent lines). Golf tees work. So will an appropriate sized bolt it you've got no golf tees handy.

- Richard

Or a 5mm allen wrench

Where are these sparks coming from/going to? Fuel line is a nonconductor

[robsGS850]

re: sparks. sorry guess i was a little sloppy with my word choice, it's more like a puff of blue flame I can see popping up inside the vacuum line every now and then. Detonation from the cylinder somehow making its way back up the vacuum line, maybe? I'm totally guessing. Hopefully it goes away when I plug the vacuum line.

[skidMarkNZ]

Yes, plug the vacuum lines (but not the vent lines). Golf tees work. So will an appropriate sized bolt it you've got no golf tees handy.

- Richard

Damn canadians making no sense with your golf lingo.

[Gyi2os]

! i'm having the same problem on my GS550. Oddly i'm excited that somebody else is too. Here i thought my tank was going to explode... But i also get the flame with the tank hooked up. (also using clear line) -side note, i'm 99% positive my petcock is up the creek w/o a paddle. That may explain why i also get it with it connected to the tank. Let me know if you guys think this is 'normal' and would go away after properly fixing the petcock. Any more details on Why this happens and things too look for would be helpful (carb related?/Valves?)

[pdqford]

noticed a lot of sucking sounds and even weird blue sparking coming from the carb's vacuum line (i'm using see-thru tubing), is this normal?

Is it popping/backfiring out the carbs? Maybe a tight intake valve is allowing some combustion to back up into the intake. With the throttle valves closed, it may be taking the next easiest route - through the vacuum line.

[Gyi2os]

Is it popping/backfiring out the carbs? Maybe a tight intake valve is allowing some combustion to back up into the intake. With the throttle valves closed, it may be taking the next easiest route - through the vacuum line.

I am. Little puffs of smoke back through the air box. I too thought about the Valves, but don't have the 'balls' to rip into those quite yet. One thing at a time for me. First is figuring out my wiring harness.