HELP WITH GSF400 MISFIRING / NOT STARTING

[MRBLUESKY]

i am having a nightmare with this bike GSF 400 , major problems with getting it started,seamed to be a fuel problem or a vacuum issue be start with as it would start if i blew fuel down the pipe.

question , should the fuel filter be full all the time ? mine fills up to about 25% capacity and tops up from there.

work done

I have changed the plugs and even fitted a new carb rack.

i dont think i have done something silly like mixing up the plugs but its got to be considered now as im running out of ideas


can anyone offer a novice some assistance with this please as ive no more hair left to pull out

[Red01]

If it runs if you blow fuel downline, might be a tank venting issue.  
Try starting it with the gas cap open.  
If all goes well with the cap open, you can start tracking down where the vent line has gone bad.

[PitterB4]

Is the petcock working?  They're notorious on the B4.  Or is it something as simple as clogged screens on the petcock?  Blocked in-line filter?  Vacuum is a good thought too.  Is the vacuum line from the #1 boot secure?  Mine went bad and I had to seal it with some sort of goop (don't remember what I used at this point).  Last, are you sure you have all the hoses to the petcock on the right ports?  Just some other thoughts....

[slavia631]

I know you said you think your plugs are not mixed up, but make sure.  I accidentally did this once after replacing the plugs, and had a hell of a time with the bike.  It would flood and would not start apart from bump-starting, and even then it would barely run.  After going ballistic for a couple hours, I came to find out later that I had just crossed two plugs.  Check the manual to verify the correct order.