what is the recomended air screw setting for 750ss? i had a flick through the haynes manual,wot a wast of time its crap,it tells you a load of crap you dont need to no,i suspect the carbs have a dynojet kit fitted,900ss emulsion tube,thin needle,. 148 main jet and a softer slide spring.
the whole subject of Mikuni 38 pilot jet set-up has always been hard to define. It's probably because you don't get a massive feedback when adjusting them like you normally do on many carb/engine set-ups. Generally could be between half a turn to 4 and a half out. If you have the Dynojet kit fitted particularly if it's a Stage 2 then you could start at around one turn out but impossible to guess particularly if not standard. Good news is (as said) as there are no dramatic changes for even a full turn, you needn't worry about engine not idling at all as a result of being a little out of adjustment to begin with. When I think I am getting close I raise idle a little and run it on one cylinder at a time on a warm/hot engine just to try and exaggerate the changes in idle during adjustment of associated pilot jet.
The Dynojet 'fitting instructions' for a 750 Stage 2 kit (which I suspect yours is because of the 148 jet) is 3.5 turns out on the pilot screw........My 750 has the pilot screws at 4.25 turns out, although 4.5 might be better. The pilot circuit controls the lower rev range running up to about 3000 rpm and the float height / fuel level setting is also part of the pilot circuit.........The higher the fuel level, the less turns out on the pilot screw etc etc. ........however, the 900SS emulsion tube may be the wrong size for the 750, even though there may be a DJ 900ss needle in it; but I doubt if it would affect idle and low rev running. The 750 Stage 2 DJ needle clip position should be 3 notches down.............I'm guessing that you might have to have yours at 2 notches down, otherwise it could be running too rich. The OEM main needles should be the same for the 900 and 750, but the DJ ones are different (according to DJ). You may also find that the pilot screw settings for each carb can be different, by up to one complete turn. AL
One thing I've found out over the last 400 miles is don't assume they should be set the same. One on my 750 is 4.2 turns, the other is 3.2 turns. I was hell bent on them being the same but it was not to be. I assume its because my float height aren't the same or the ware on the carb parts.
thanks for the tips,i had a look through all the old paperwork and it is a stage 2 dynojet kit,i also found a few dyno readouts from when it was fitted.
