Just fitted the wideband afr today and tried setting the carb and this is where I am: 700 rpm engine hot with the afr reading 14.7 when I blip the throttle it falls to 13.5 but, then as revs increase the afr goes up to around 15.5. is this okay what should it read at various revs, this is of course as you see with out an air filter fitted with the choke fully open and the engine hot. I am currently renovating a standard oil bath one and fitting a plenum chamber like @mikedjames did but, its not quite ready yet.
As I understand it 14.7 is the number to aim for under all driving conditions .. obviously this will increase when accelerating but should drop back around cruising speed .. I'd also say it needs to be close to 14.7 at idle with no choke .... This is my understanding and how mine is but may well not be 100%
The 14.7 AFR target is for the idle setting. This is actually quite a 'hot' mixture and if you maintained it when the engine is delivering full power, things may melt. If you fit larger jets than optimum then you can compensate for the lack of preheated air - and if you drive gently you may not see a problem either. If you floor it the flat spot becomes unpleasant, as it goes lean because the air flow collapses as the second throttle opens fast, then it goes extra-rich as the acellerator pump spray jet cuts in, then it settles down again. When you accelerate, or you are going up hill on a motorway, it should drop to about 12.5:1-13:1 to ensure you are able to get power without overheating - having a bit too much fuel means cooling by evaporation as well.. Cruising on a motorway, it will climb to 16:1-17:1 which is OK because the power output is lower at the same RPM and if you lift off completely going down hill, it will go to 20:1 .
