I have one if the many carbureted Z1 Classics that came with fuel injection. Shortly after my purchase- seven or eight years ago- my mechanic put a different set of carbs on it and I noticed an occasional spitting back through the carb at number 4 cylinder. It primarily spits when it's under 4k rpm and I assume it to be a vacuum leak.
I recently retired and moved and have time to try to get it running right. I put a good set of VM 28's along with brand new intake boots and assumed the problem solved. NOT! Next was to take the number four injector holder bracket off and reseal and replace it. This seems to have helped some but I'm still getting spitting back through the carbs on number four cylinder.
Next thing to check is a compression check. I'm thinking it might be possible that there's carbon on the exhaust valve that's causing the problem- that's for tomorrow!
Anyway-any of you guys dealt with something like this before and even better- how'd you fix it?
