This is the scenario: Amal 389 (1 5/32 bore) slide 3, (chrome plated), main jet 420, and 25 pilot. This is how the carb is set up. Needle on second from top notch and no air filter, just a small chrome open bell mouth. The carb mixture is spot on. In order to prolong the life of the Amal, I wish to fit an air filter. Does anyone know what changes will be required to the jets and needle, or anything else for that matter? What I want to avoid is a prolonged period of experimentation swapping components and doing plug chops. I assume that the correct values must be available somewhere. The engine is a Super Rocket engine fitted with the late type large inlet valves. As a matter of interest has anyone had their cylinder head overhauled professionally, and if you have what are your opinions about the standard of work carried out? My head has been removed because I was burning oil on the N/S cylinder. What I discovered was that the inlet guide was loose in the head casting. As an aside, here is a useful diagnostic aid (apart from a smoking exhaust that is). I noticed that as the engine warmed up the tappet noise changed from the normal tap, tap, sound to a ringing, ting,ting,ting sound. I should also add, that the engine never smoked when cold, and that it never smoked heavily.
