Trying to isolate an issue with my new 2002 GS.

Out of about six rides, I've run into problems with the throttle remaining open despite rolling completely off the throttle... usually this has happened coming to a stop, but once it happened at low speed (1st or 2nd gear, I can't recall).

In one case just rocking the handlebar back and forth cleared up the problem and the bike began to idle normally, but twice I had to kill-switch it, whereupon starting it up again it worked fine.

I was originally chalking it up to newbie user error (the same thing happened on a Honda Nighthawk at my MSF class) but a friend now mentioned this is potentially dangerous - and once I stop scooting around the neigborhood and start riding distances at speed I agree it's not where I want it to happen again!

Does this sound like a simple lubrication issue of the throttle cable?  Or should I be looking in other places as well?

Your problem is likely to be one of four things - in the order I would check:

1. Improper freeplay - adjust to spec with the adjuster or adjusters at the throttle (I think pre 2001 bikes had a single throttle cable, my 2001 and later have push-pull throttles with two cables)  while on the side stand, start the bike, turn it all the way to the side that makes it rev highest and adjust until the revs come down.

2. Cable improperly routed - in other words, turning the bars is pulling everything - cable, cable housing etc - if the tank has been off at the same time as the throttle was off it could have been mis-routed.  Could happen when changing handlebars as well.

3. Linkage return spring problem down at the carb

4. Carb is rusted/corroded and needs cleaning & Lube - could be if the bike sat for a long period.

I am thinking it is definitely #1.

I noticed (with the engine off) that adjusting one of the two cables made a huge difference in the throttle action - before it probably required (unbeknownst to me) some subtle pressure from my hand to begin to close, and after a loosening the throttle now snaps back immediately with no effort.

Now it appears I have to follow your advice and watch the revs as I move the bars back and forth.

A follow up question - how do you know when the two cables are properly balanced?  In other words, can one be too loose and the other too tight?

Quote from: tophI am thinking it is definitely #1.

I noticed (with the engine off) that adjusting one of the two cables made a huge difference in the throttle action - before it probably required (unbeknownst to me) some subtle pressure from my hand to begin to close, and after a loosening the throttle now snaps back immediately with no effort.

Now it appears I have to follow your advice and watch the revs as I move the bars back and forth.

A follow up question - how do you know when the two cables are properly balanced?  In other words, can one be too loose and the other too tight?

It is what is refered to as a "push-pull" system.  One cable pulls the throttle open - and that is probably the one that was too tight.  The other actually pulls the other side of the linkage closed.  So long as it does that its OK (note that there is also a spring that pulls the throttle closed - the second cable just makes absolutely sure that you have a positive mechanical way to force it closed in the event something jams.  So, you can look at the bottom end of the cable - at the linkage area and make sure that when the throttle butterfly is in the fully position the correct cable has just reached the point where there is no tension pulling the throttle further in the closed direction.  The other cable - the open cable -should still have a bit of slack no mater what position the handlebars are in.