Had idle set at about 1500. Did what you have suggested by turning idle back but it only drops the revs a bit, no where near enough. Its a mystery. Gonna have one more go tonight but if i don't get anywhere il set them up on bench as i have been doing and leave it at that pretty pigged off tbh. What i don't understand is i can balance the front two and the back are pretty spot on but its balancing backs to the front, just throws everything a mile out.

Doesn`t take much leaning on the screw driver too hard to upset the carbs , try a blip on the accelerator after every turn of the screw driver just to settle the carb down, see how that goes

If its running out of fuel during balancing the revs will rise. (It starts running lean) You will go round in circles trying to set up carbs without a decent fuel supply. Sucking on the vacuum pipe then bending it over will probably not work, you might just be running the carbs dry as you work. Get a proper temporary tank to supply the carbs, £20 off eblag.

Damien420 wrote:Had idle set at about 1500. Did what you have suggested by turning idle back but it only drops the revs a bit, no where near enough. Its a mystery. Gonna have one more go tonight but if i don't get anywhere il set them up on bench as i have been doing and leave it at that pretty pigged off tbh. What i don't understand is i can balance the front two and the back are pretty spot on but its balancing backs to the front, just throws everything a mile out.

you dont balance backs to front.

you balance all 3 carbs to the one that is fixed withtou the adjuster screw.

perhaps you ahve a vaccum leak or the adjustr screws are in too much if the idle wont come down.. backing out the idle adjuster too much should stall the bike.. if it doesnt your balance screws are in too much and holding butterflies open.

Success
Thanks guys for all the advice, i took it all on board including a proper temporary tank and with a fresh start it was balanced in about 10mins. Think it must have been the fuel supply as thats all i really changed.
Onto the next issue

After reading some posts on here i decided to change the pilot screws to 1 1/4 turns out as thats supposed to be correct. Its an 89 import but it now runs a bit lumpy like it has a miss fire. Should i change it back?
Whats everyone's opinions?

Well, if it was running fine before you changed the pilot settings, then change them back...or did you do this along with some other changes? What do you have the idle set to?

No changes just cleaned and new seals. Pilot screws only thing i changd, idle set to about 1200-1300

Damien420 wrote:Success
Thanks guys for all the advice, i took it all on board including a proper temporary tank and with a fresh start it was balanced in about 10mins. Think it must have been the fuel supply as thats all i really changed.
Onto the next issue

After reading some posts on here i decided to change the pilot screws to 1 1/4 turns out as thats supposed to be correct. Its an 89 import but it now runs a bit lumpy like it has a miss fire. Should i change it back?
Whats everyone's opinions?

What is your frame number? only the earliest of early nc30s has 1 1/4 setting.. some of the later 1989s follow the later carbs at 2 full turns out.

did you put a dot on a screwdriver to count the turns properly? i.e. not half a turn.

At work at mo so dont have frame no to hand. Put a yellow dot on handle end so deffo got full turns. Going to put it back to 2 turns out and see what happens.

Was hopeing to get it running nice for weekend as iv never had the full easter wkend off but someones just said its due bad weather Typical!

If that is the only thing you changed and now it's running like a turd, change it back and see if it cures it.