Hello, I am new to this forum and have a question about my 73 914. It has a 1.8 with dual 40's. I know the engine is not original but is otherwise stock. My problem is it backfires when blipping the throttle or in between shifts. I have checked and rechecked timing, valves and carb settings. Compression is 125 across all cyls. I have also checked for intake leaks. Could it be an exhaust leak?? I currently have a 009 (I know, I know) but am replacing it as soon as I can get some good advice on which one would be suitable. Any help would be greatly appreciated as I am getting very frustrated. thanks

5: Welcome to the Club. Webber carbs and a 009 are what I run on my sand rails, check the exaust system for leaks. If its poping out the carbs its too lean, out the exaust, its to rich and the unburnt fuel is mixing with air leaking in the system and poping. Do you read spark plugs? They sould be a rich tan.
Joe