Hi all, first time posting.  I bought a 2001 s40 about a month ago.  It had approximately 2,500 miles on it.  Thanks to these forums, I made saddle bag supports and moved my rear turn signals to the license plate all with stuff I found at Home Depot.  Saved myself about $100, so thanks for that!  (want to see pictures?)  The previous owner said that it had sat in the garage for the past year.  It was idling high and running rich.  I took it to a dealer with certified Suzuki mechanics and had them give it a good once over and give it a tune up.  Everything's stock from what I can tell.

Here's what they did: Changed oil and filter, changed spark plug, replaced float gasket, replaced needle valve assembly, replaced pilot jet, replaced needle o ring (from parts invoice).  Their notes narrative say "Cleaned carb replaced float valve, properly set float height.  Set drive belt tension, tire pressures, etc.  Attempted to tune out backfire.  Some backfire on decel is common with this model.  Bike has had carb work done before."

So when I got it back, I was excited that it ran like a whole different machine!  Then after riding it for a few weeks, I've started to become rather discouraged.

It seems to be running out of gas too soon.  For example, today at work I had to put it on reserve to get it started.  I went to the nearest gas station to fill up, and she only took 1.55 gallons.  That means there was 1.25 left in the tank.  Reserve is supposed to be .6 gallons, right?

It hates to start up in the morning.  I'm talking May in San Diego mornings, like 60 deg F, maybe 55 at the lowest.  The "choke" does nothing for me.  In fact, if the bike is running and then I pull the knob (even the slightest bit), it kills the engine.  So, without the choke, it'll start up, but then stall after 30-60 seconds.  I have to stand there holding the throttle open a bit for several minutes before I can let go or it just stalls again.  Some times I just jump on and ride, restarting it at stop signs along the way to the highway.  Seems nice and warm by the time I get there.  I marked the idle adjustment screw so I knew where the mechanic had it set.  Then I turned it up about 3/8 of a turn.  That was great in the afternoon when it was warmer out.  Next morning, 55 degrees, the whole stalling routine again.

Today leaving work in reserve, after filling up and switching back to "FUEL" from "RES" it stalled on me before I left the gas station parking lot.

I've read about the Raptor petcock and the white spacer mod.  I'm a mechanic (I work on H-60 helicopters for the Navy) but have never done carburetor work or motorcycle work.

Open to any and all suggestions!  Thanks in advance - Cass

Ok, I did the leg work for you.  

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1251932429/1

There is no fuel pump so if you have 1.5 gallons left, it should run. The petcock is probably the culprit.

Do you know what size jets the dealer installed?

That's the stock size.

If it were mine, I'd leave the dealer alone and read threads on this site pertaining to the inner workings of this carb. It's a very simple carb. If you can work on a helicopter, you can open up this carb. Clean everything thoroughly and make sure your jets are at least stock and the dealer didn't install huge jets or something. It will at least be a base you can start from.

I have a brand new S40.  Some of the issues I found were...

1  Belt way too tight

2  When I did the valve clearance check the spark plug was finger tight. Valve clearance was good.

3  The bike, at times, seemed to run out of power other times it had lots.  I put a Raptor petcock on and seems to run fine all the time.

I suspect your petcock is faulty.  My bike only has 2400 miles.

Thanks everyone, looks like as I anticipated, I'll be going with a Raptor petcock.  I'll make sure to get the real deal and not a knock-off.  Now here's another question: should I drive the cage until I get the petcock swapped?  I'm ordering it tonight, but I don't want to do any damage. Oh, and when I put the line into the gas can and switch to PRIME, is that going to drain the whole tank out?  Don't want to try using too small of a vessel...

Prime will drain the entire tank.

You can't hurt the bike by running it with a faulty petcock. It just may not run. You decide.