My bike quit on me three times during my 14 mile commute on a hot afternoon.  It was having "no fuel" symptoms.  The first time, I did a lot of roadside fiddling before I finally suspected vapor lock in my very non-OEM fuel filter.  The filter, due to its weight and not being attached to anything other than hoses, drifted closer to the engine over time.

I popped a hose off the filter (and got hit with a quick blast of gasoline spray -- hmm, there should be no pressure here) and reconnected it, and it ran just fine for another 5 miles.

I am going to relocate the filter and mount it to something more rearword, and I'll report the results.  This might be one reason the stock GS doesn't come with a fuel filter (besides suzuki being cheap bastards).  Usually, you'd have a pressurized system and a vapor return to avoid such a problem, but a gravity fed system won't accommodate that very well.  (My filter has a vapor return, but of course I had to cap it off.)

So I guess this is a word of warning, if my theory is correct, for folks adding a fuel filter.  Keep it cool.

Do you remember from which side you got sprayed from?

From the hose coming from the tank?

Or, the one coming from the carbs?

Or, did it come from the filter, in which case, from which of the above was it connected to?

If the filter is supposed to be vented...

It was hard to tell, since it was already dark, but it seemed to be coming from the filter.  I unhooked the filter-to-carb hose with the filter in my right hand, and most of the gas smell was on my left hand.

As for the filter's vapor return... I ask you what should I hook it up to on a gravity feed fuel system... a snorkel? 

However, if I actually follow through on my stupid "fuel pump on a GS" idea, I could put it to use.

If it came from the filter side when you disconnected the hose connecting the filter to the carbs,  you could have just built up some vacuum pressure in your tank......

The first thing I did was open the tank to see if I had screwed up my odometer measurement, but there was plenty of fuel, and no sucking noise.

So whats the best way of cooling out fueling system?


Run it in that insulating foam used for hot water systems?

From what I've read (about old VW beetles, and airplanes) is that most of the heat near the engine is radiant, so a simple metal deflector should do the trick.  But I figure I'll be fine just mounting the filter farther from the engine, because there's a lot of air flow anyway.

Pressurized fuel systems avoid vapor lock by being pressurized (duh) and keep the fuel always moving, which keeps it cool.