I have a 1978 motto guzzi robin. Seems all original, less then 300 miles. I just got it running. New plug, cleaned carb and new carb gaskets, cleaned tank. It idles well on choke, even rides with very little power. Idles decent off choke after warmed up but bogs and dies with anything over 1/4 throttle. Iv sprayed around and the the carb and there is some air leak at the slit between carb clamp and body of carb. It has a plastic spacer/shim (which is now stuck in the carb). But I tried with an o ring and shim and just the shim. I can't seem to get it to seal. Any tips on getting it to seal? I'll probably have to break the shim to get it out of the carb.