Does any one have any ideas as to what would cause the smoky grey/white deposits in the barrels of my Rochester AA on a 1950 Rocket 88? I stripped the carb down because, once it gets warm, it’s hesitating at anything over 40mph.

 

I don't see any abnormal wear on the carburetor in the pic. You can see where the throttle plates have slightly worn the carburetor bores moving over years and years. I'd be more concerned about the throttle shaft bushings than that wear though.

 

I am going to guess the deposits are from the additives in the petrol you use across the pond. I would think a dab of SimiChrome would remove the deposits.

Now would be a good time to check throttle shaft looseness.