Hey guys, looking for a few suggestions here.  Recently I've had some throttle stalling issues with a newly purchased gs500.  I found out that the bike runs great on PRI but no on ON or RES.  It seems to stall out when I give it throttle and die while riding, has idle issues, and starting problems.  So I double checked my vacuum line, replaced it, I have vacuum (pulses).  I took apart my petcock and cleaned it out, most likely the problem could be attributed to that diaphram that's mounted on the side of the petcock?  So I came to the conclusion that I needed to replace it, go online to order and there's some nationwide back order on that part that won't be at my door until the middle of September. 

So, my question is what potential issues will I face in the long run/immediately if I ride my bike around in PRI and switch it back to ON when it's off.  I know that I won't have the reserve functionality but will this cause damage to my bike?

Thanks in advance for any advice!

Check for a leak in the vacuum tube going to the petcock. Sounds like it is not opening fully to allow fuel to flow.

Prime and reserve have a smaller orifice in the petcock and can lead to fuel starvation at high speed and upper rpms.

This is way cheaper than a stock replacement.I haven't done it on a 01+ bike.Should be pretty much the same install.
http://gstwins.com/gsboard/index.php?topic=56352.0

Thanks guys, I replaced my fuel petcock and that fixed the issue!