'82 GS850GL Fuel issue

[Rubic]

As I said I have an 1982 GS850GL. Bought it in 2010, then it sat in '11 and '12, took it to a shop early this year and had them do carb work, replace the rubber, they also worked on the brake master cylinder and cleaned out the tank. Bike runs as good as ever EXCEPT when I get to half a tank, It just dies. Acts like there is no fuel in it, except I can visually see and hear it. Tried turning the petcock to reserve and even tried prime, no bueno.
If I refill it back up, works again just fine again.

So long story short, is it an easy-ish fix for someone with only basic tools? Or should I go back to that bike shop (or perhaps a different one...) and tell them to fix it?

Rubic

[Agemax]

check the breather hole in the fuel filler cap is free and not clogged. next time it cuts out at half tank, remove the cap and see if the bike will start up again.

[tom203]

Also pull petcock and check to make sure the filter ain't gunked up.

[eil]

Or should I go back to that bike shop (or perhaps a different one...) and tell them to fix it?

It doesn't sound like a carb issue, so that's probably barking up the wrong tree.

The standard advice around here is not to take your bike to _any_ shop. To the inexperienced, it's hard to identify a good mechanic. And equally hard to identify a bad one until they've already done some damage. Once you know enough to spot a good or bad mechanic, you won't need one!

These machines are fairly easy to work on with only a modest set of tools. And since you're here, you now have free and nearly instant access to hundreds of years of collective motorcycle repair experience!

And, depending where you are, there's a good chance that someone local can stop by and assist you for only the cost of a beer or three.