first 1/3rd of a new tank of fuel

[TheOzTurkish]

while I'm here.

EVERY time I refill the tank, for the first 1/3rd of the tank the bike seems to run flat, like its laboring and asthmatic, it starts fine, idles fine and generally runs fine.

for example normally when warmed up it will pull all the way through the rev range  BUT after filling the tank when warmed up around 6000 RPM and it feels like its outta breath UNTIL I go through about 1/3rd the tank (normally about 120-150km) and then its back to its normal buzzy self.

I always fill up at the same petrol station and always fill up with 91 octane.

Any thoughts with this??? there are no intake leaks and I've had the fuel lines changed recently but its been doing this since I got the bike.

[adidasguy]

Probably the gas tank vent is dirty and air not getting in. To be sure, run with the gas cap loose. If things OK, then take it off and clean out the vent hole. If you still have problems, then we ned to look elsewhere.

[BockinBboy]

Probably the gas tank vent is dirty and air not getting in. To be sure, run with the gas cap loose. If things OK, then take it off and clean out the vent hole. If you still have problems, then we ned to look elsewhere.

I'll put a +1 on that!

- Bboy

[Chucky]

I had this problem, I put a tank of 98 in it and it cleaned it up, after having done this i always try to put 95 or higher in it, I only put 91 in if the servo has nothing higher (it still feels like crap every time I put 91 in)

In saying this im no mechanic so just give it a go and see what you think.

if in doubt, go flat out

[noworries]

Chucky's spot on...nuffin better than an Italian tune-up to clear the odd prob on the old GS.