reserve never flow problem

[mason79]

i noticed what ever i do with the fuel lines below, i can't seem to get the reserve on either left stock vacuum petcock nor my right manual petcock to feed gas while at the reserve level.

they are t'd to a filter and t'd to off of that to feed the carb in's.

my experiment was to run it all the way down to reserve and like a normal situation flip that bitch and behold gas, but...no such luck, i coasted to a dead still and had to pour the gallon can into the tank just to get started and i had a scare cause it just cranked,

and i was on the shoulder of an uphill facing freeway with no out, a pickup truck pulled over and guy walked up to me, i hit the button again after, i primed the left petcock,and it fired, ran flawlessly with gas. thanked the man and rode off like an xs should and did.

why did the manual petcock not feed gas, help! this is my third replumb in all confirgurations and not to access reserve, is not good.

[81xsproject]

Maybe the screen towers came off and aren't there to stop the "ON" flow until all the gas is gone?

[mason79]

huh?

the mike's xs petcock has long and short snorkels to capture gas at differnet level, taller for yada yada.

yeah one cheap screen fell off of that, , i don't think it matters.

the stock petcock(vacuum) has screens intact.

[79XS11F]

If there's still gas in the tank but no flow on reserve then perhaps the lower fuel supply section or of the screens is plugged. Does "prime" work?
Rob

[oseaghdha]

Check for flow on reserve when the tank is full.
Then you can at least find out if the passages are blocked.
If that works, maybe there is a problem with the level control.

[mason79]

i don't know what you mean by level control, but i went ahead and cleaned out the cap vent, that is a new revelation to me, it appears upplugged but, thank you this site for the old thread.

and it flow on prime and the manual flow on reserve, i'll check the flow of the vacuum one later, thanks again.

[mason79]

thanks guys it was the cap vent, i didn't see any obstructions, i guess there was some and low fuel level couldn't overcome the vacuum in the tank.