engine fires but will not run for more than a second or 2

[hoppy57]

GS550 1978,engine turns over fine and fires but just dies as soon as starter is released,has boyer ignition and bell mouth filters,has been sitting for the last couple of years,put new petrol in,always ran rich when it does start,assumed down to the bell mouths,any help appreciated.

[sharpy]

Have you pulled the carbs apart and cleaned them real good? Whats the compression like?

[steve murdoch]

Carb cleaning tutorial can be found here.

http://members.dslextreme.com/users/bikecliff/

Velocity stacks and a straight pipe will require major rejetting.