We had that exact issue Barry. We had our ICT's fitted to a type 1 motor and the right hand carb was horrendous and backfire, spat, basically wouldn't run for love nor money except for tickover. We eventually traced the issue back to the carb not sitting right down on the inlet manifold because it trapped one edge of the carb onto the tinware (Empi inlet manifolds made wider than stock manifolds) - I know ours was a different motor all together but it may be worth investigating.
I bought some of those 6mm wooden spacers, I made sure the carbs were sat properly when I fitted them cos I had the problem you had with my previous carbs
Get your carbs nice and warm. Disconnect the linkage. Hopefully it'll idle ok. Tweak each mixture screw in a bit at a time - let it settle - until that side stumbles (not getting enough fuel). Back it out a bit. Do the other side. Connect your linkage, tweak the linkage connectors until you get a nice idle and both sides are sucking more or less the same. Take it for a blast, whip a plug on each side out and see what colour they are.
Mr Haynes, Mr Haynes it has been on here for ages, I don't know anything about it, What exactly is dogging?
Sometimes a backfire problem that seams to be a carb problem is actually an ignition problem. I had this once with a customers van . Same carbs you have. It turned out he had the wrong type of coil fitted , which wasn't compatible with points and a condenser.
I would say it’s the carbs because before I took the carbs off to change the needle valves and set the floats correctly it wasn’t backfiring through the carbs but was backfiring through the exhaust,
Possible it's ignition timing, but I'd say your backfiring is too lean mixture. As I mentioned, I got some pretty impressive flames out of my Dells when i was backing off the idle mixtures. Quite destructive, so best avoided. Exhaust: big, senior citizen-killing backfires likely poor ignition: unburnt mixture builds up, then eventually gets ignited and explodes in the exhaust. Snapping and popping on the overrun likely a hole in the exhaust (less back pressure) or a very free-flowing exhaust/hotter cam. My van snaps and pops a bit on the overrun - not sure I can (or want to - sounds quite cool) get rid of it. Sure others will chip in.
Well if it was ok before you worked on the carbs then it must be something you have done to the carbs. Have you taken off the manifolds and used the old gaskets. start it up and spray some easy start around the carb. If the revs rise you have an air leak. spray some down the carb throat too listen for an improvement. If it does there is fuel starvation on the left or right carb.
