MKIII popping a lot when revving

Definitely sounds like a lean condition. Unless you are going to ride the bike, I'd defer trying to fine tune the carb in the winter. Wait until you get some warm weather where you can get the engine really warmed up to dial in the carbs. It's the nature of Amal carbs to run lean when cold. If you try to get it to run right cold it will be too rich when warm.

I would say with the old Amals the problems are invariably the pilot jet or needle height. Assuming everything else is to spec the Commando seems fairly tolerant to wear in the carbs. As mentioned air leaks in the exhaust could be a cause but normally on the over run when shutting the throttle.

I've had a few of the popping scenarios. I've had the exhaust leak popping when I released the throttle. I've had a cracked intake manifold from overtightening the bolts popping, and I've had the plugged pilot jet popping on one side too... I'm sure there's a few more I haven't had,... YET.

The exhaust one happens when you're riding along and back off on the throttle... pop, pop, pop. It's pretty distinctive

The cracked intake can be hard to diagnose, I used a can of carb cleaner to spray the outside of the intake manifolds on a nearly invisible crack which made the bike stumble every time I sprayed it. You couldn't see the crack, but when I unbolted the manifold, it fell into 2 pieces.

The plugged pilot jet was simple to remedy because I have 3 guitars...

Fast Eddie said:

A faulty Luca Rita would be bottom of my list of suspects.

I used them for years, road and race, never had one fail.

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I have heard good thing about the Rita too. However a friend's Rita on a 79 T140 did go bad. He was lucky enough it get it fixed-supposed to be very simple.

acotrel said:

There is a difference between a miss and a pop. If it pops as you shut the throttle, it is probably due to an exhaust leak. If it misses as you accelerate, I'd be looking for a faulty electrical connection or perhaps a spark plug with too cold heat range. If you have got the needle and needle jet slightly too lean or correct, you will get a cough as you open the throttle in cold weather, until the engine warms up.

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It is a pop when closing the throttle. Plugs are stock heat range.

The way it was explained to me a few years ago by someone more knowledgable about such things than I: The RITA is an old fashioned and simple system, made with high end components. The modern Boyer is a more modern system, made with cheapo components...

Dyno Dave is the resident expert, but having worked in tech I can tell you that electronic components, most generally, get better and less expensive as they evolve. When I started working at EMC megabytes sold for $3.00/ea. Now-a-days gigabytes, even solid state ones are considerably less and much more reliable.

I have drill bits on order to clean the pilots- go from there. Temps are falling this week so no riding in the near future (month!)

Update-When I cleaned the pilots I found one plugged and one is missing. I will be drilling out the remaining pilot and installing screw in MKII pilot jets.
I checked for air leaks and made sure my exhaust pipes were tight. Should have the jets by the weekend.