Just the other day I posted a new fuel filter option to the tech section. I've run a few tanks of gas around town, and while the level would fluctuate, I never had any issues. Today at the end of a 180 mile trip I suffered vapor lock twice. Despite having over 1 gal of fuel left, the filter bowl would run dry until I sputtered and died. After waiting for a minute or two, the fuel would flow until it reached the level of the inlet tube inside the filter - about halfway full.  The first time it occurred was during some moderate highway stop and go 2.5 hours into they ride, and the second time was during city riding 30 minutes later - closer to my destination.

What is the best way for me to prevent this? Do I need to find a way to bleed the air out if my fuel filter? This is a problem I'm not very sure of.

As a side note, bike is an 01 with 9,7xx miles,  has a Chinese imitation raptor petcock that has never had flow problems, and the entire set up more than passes the cup per minute flow test.

The filter:

and another issue could be water in the fuel.
it will coat the filter and block flow of gas.

If the fuel tank is clean, and you carefully cut and install clean fuel line that is intended for fuel use - there is really nothing that should get past the stock screens on the petcock.  I have never had trouble with dirt or water in any fuel that I have purchased.....but that doesn't mean you will never have a problem.  (Occasionally someone will post a thread about getting bad fuel).  The carb also has a filter screen located on top of the needle and seat assembly.....so I am not sure how junk would get from the fuel tank - past the petcock and carb screens.

Is the loose fuel screen issue you are having with a Chinese raptor copy?  That might be another reason to spend the extra $ 10 and get a real Yamaha petcock.....I have never heard of the filter screens falling off the stock petcock or the Yamaha part.  Additionally the outlet pipes on the Chinese copies are smaller OD, and the brass nipple is machined instead of being flared tubing - so the ID of the outlet pipe is significantly smaller than the Yamaha Raptor petcock.  The Chinese copy may flow enough fuel when you allow it to flow through an unrestricted fuel line into a cup - but when hooked up to a inline filter or the carb they will "air lock" easier than a petcock with larger tubing.

Debris does collect in the bottom of the carb float bowl - but that doesn't mean that some fuel sloshing couldn't ever wash something up into the pilot jet on occasion.

My belief is that most issues with carbs getting gunked up occurs from being stored with fuel in the float bowl repeatedly....or for long enough periods that the fuel can evaporate and gum things up (result in  concentrated ethanol content in the float bowl.  If you are going to park your bike for a while....shut off the petcock and run the bike until it stops running....or drain the carb if you have a drain screw on the bottom of the float bowl.  This helps prevent the pilot jet from being clogged when the fuel evaporates or decomposes.

I am not trying to force my opinion on anyone.....and when you were posting about the new filter you found, I kept my opinion to myself.  Some folks like to run inline filters, and sometimes they work fine, and as you discovered sometimes they don't work.  The problem comes into play when you start getting air bubbles trapped in small fittings or high spots in the fuel line routing.  The gravity system provides very little pressure to overcome restrictions......for gasoline every 3.08 feet of elevation difference results in 1 psi of pressure......so even with a full tank the fuel system on the Savage is operating on less than 1/2 pound of pressure.  This is not only an issue in a gravity fuel system - I work on water lines and sewage force mains and whenever you have a high spot in the line it is necessary to install an air release valve.  Trapped air in a pipe can cause a horrible restriction to flow - as the air bubble causes the water to flow under the trapped bubble......and sometimes it can prevent any flow from occurring.

I no longer add an inline filter to any gravity fuel system.  If I got crap in the fuel tank, or if the tank is rusty - I take it off and clean it.  I rely on the stock screens to keep junk out of my carb.

     

verslagen1 wrote on 11/25/14 at 16:19:13:


That could be a spot where air is trapped, and fuel cannot flow under or around the bubble.

http://en.wikipedia.org/wiki/Air_lock

filter is wayyyy too big
get a smaller body cone shaped one
been running one for 13 k no probs also its a non paper element
kinda metal lookin gold colored element