elpks

Hi Triumph-V8, Thanks for responding. I think your last piece of advice is the route I need to take - without any measured data I'm just guessing. I need to get a wideband sensor plumbed in. Thanks, Phil

Hi, I'm trying to eliminate a lean backfire on my 2.0 litre Pinto engined Westfield. The backfire occurs towards the end of progression at about 2500rpm, just before the main stack tips in. The carbs are 6 progression hole DHLA 45 D with standard lotus spec 10 parts (see below). They currently have 7850.9 idle jet holders and 56 idle jets. I can fix the issue by fitting the 60 idle jets I have, but then it becomes too rich at lower rpm (it starts and runs beautifully from cold). Do I simply move to a richer idle jet holder, say 7850.1, and move back to the 56 idle jets, or is it not as simple as that? Carb Type ....................... DHLA 45D Choke .............................. 37 mm Main Jet ........................... 135 Main Air Corrector Jet ... 150 Main Emulsion Tube ...... 7772-8 Idle Jet ............................. 56 Idle Jet Holder ................. 7850-9 Pump Jet .......................... 45H Power Jet .......................... 70 Any advice greatly appreciated, Thanks, Phil