Recently bought a GK76a GSX-R 400, but it's only running on the 2 right hand cylinders? I'm guessing carbs as the coils do one cyl each? Will be getting a better look at the weekend(comp check etc) but if anyone has any suggestions otherwise?

1 coil does cylinder 1 and 4, the other coil does cylinders 2 and 3. You might wanna make sure they go to the right cylinders. Check for spark on each. Apart from that clean out the carbs and make sure they are ok. Then you should be running on all 4.