Hey.  I just got my license (took and passed the MSF Course last week,) and finally started driving my GS on the road.  The bike was idling kind of inconsistently, and when i came to a stop and/or let off the throttle, the bike wouldn't return to idle speed right away.  Well, I just realized I had my petcock set on PRI while I was driving the last two days. 

My question is (and I searched for it and couldn't find it): would the petcock being set to PRI cause, or be related to, the inconsistent idle and slow return to idle speed?  I know it's not good to drive with the petcock set to prime, and I have since corrected my mistake. 

I will test my theory tomorrow after I get home from work, but in the mean time I would love to hear your opinions.

Thanks.

Prime just lets the fuel flow without a vacuum signal from the engine, it shouldn't affect anything if your carb floats are working correctly.

-Jessie

Quote from: tialloydragon on April 10, 2010, 07:21:37 PM
Hey.  I just got my license (took and passed the MSF Course last week,) and finally started driving my GS on the road.  The bike was idling kind of inconsistently, and when i came to a stop and/or let off the throttle, the bike wouldn't return to idle speed right away.  Well, I just realized I had my petcock set on PRI while I was driving the last two days. 

My question is (and I searched for it and couldn't find it): would the petcock being set to PRI cause, or be related to, the inconsistent idle and slow return to idle speed?  I know it's not good to drive with the petcock set to prime, and I have since corrected my mistake. 

I will test my theory tomorrow after I get home from work, but in the mean time I would love to hear your opinions.

Thanks.

running on prime might lean it out a little at highway speeds as it doesn't flow as much, but you'll notice if it does. commuting ( <70 or so) shouldn't hurt at all... but you'll lose reserve completely, which is not fun.

sounds like you need to adjust your idle up a little. once the bike is completely warm (IE, after a 20-30 minute ride)  turn the thumb screw UNDER the carbs one way or the other until your tachometer registers around 1200 rpm. make sure your choke is completely OFF and this is a good setting.

if you're still hovering/floating at idle, completely warmed up, then there is likely a vacuum leak, partially clogged idler jet, or your valves need adjusting.

there is a thread specifically for this.