poor idle problems ...more help needed

[royster81]

aggghh the problems continue ....

so the bike idles low (around 1k) and almost hunts for somewhere to sit (flicking up and down 1k to 1.6k) and when you give it a bit of choke it sits nicely at whatever you want then when warm it still hunts for somewhere to sit and around 1.6k

or

if i adjust the idle screw so it idles better (or stronger and it stops hunting ) when it's warm it idles at 3k

i have balanced the carbs using rick olivers method which i'm fairly happy with and they are seated properly ,no leaks, but this is doing my fcuking head in,the castrol bike idles so well compared to this and gareths bike is the same

i have changed plugs,reset the carb balance,could it be something as simple as the A/F screw needing set somemore or the carbs being balanced by an idiot and needing set right
the bike rides ok everywhere else but at idle.....

please help as i'm begining to pull my greyhairs out

[wullvfr]

idle should be adjusted when its warm........so let it warm up then set idle to what it should be,if its a nc30 then 1,300rpm give or take a hundred rpm.

[wullvfr]

also if it idles erratically and doesnt idle smoothly then the valve clearances may be out. :D :D

[royster81]

idle should be adjusted when its warm........so let it warm up then set idle to what it should be,if its a nc30 then 1,300rpm give or take a hundred rpm.

it won't run at that speed....

[Cammo]

Are you sure the idle screws are all set properly?

2.25 turn out is the usual figure mentioned, but I've seen some standard-ish bikes not like that setting at all.

[royster81]

Are you sure the idle screws are all set properly?
2.25 turn out is the usual figure mentioned, but I've seen some standard-ish bikes not like that setting at all.

thats what i'm going to check today buddy,it's one thing i can honestly say i did once and have forgotten what it was set at but the carbs are coming out again (8th time in a week i think) and i'm dropping the jet sizes again and messing about with the A/F screws to ,as you say 2.25/2.5 turns

[CMSMJ1]

Is this your bike with open carbs?

[royster81]

Is this your bike with open carbs?

no matey ,i set the balance on those carbs the same way i did these carbs and the open ones are fine but these ones are funked up...both set using the same method,i dunno

but i'm just back from the garage,fingercrossed the idle is now sorted out ,the A/F screws where set at 2 turns out ,so hopefully this will be the reason behind the poor running at idle
jets changed also but hopefully no more bangs coming down the revs

i have a lot of hope for today

[royster81]

got the balancing right (i think) but the jets where wrong and it ran like a bag'o'shite so big out they came,i'm getting good at this,carbs in/out and sorted in around an hour,with a break for a brew of course

[MexicanGringo]

When you put the carbs back in be sure to tighten the hosecalmps round the rubber seats, intake air leaks completely fk a/f mixture (and obviously youv reinserted the intake screws from balancing).. Are all the basics taken care of, new air filter, cleaned plugs & plug gap(0.6-0.7mm)my nc30 was completely bogging with fast fouling plugs, diaphram letting fuel to carbs? float heights(make sure the little spring loaded pins in the float valves arent sticking) Make sure the bystarter(choke) lever returns properly when warm, this linkage tends to become sticky when the petrol is evaporated from the carbs.. If the idle is varying the a/f is varying too,or maybe your 'butterfly' valves are loose from wear. Was this hunting a problem from the start or only when jets were changed? What jet size are they?theres a lot of theory/bullsht regarding jet changes when installing a new exhaust, the factory sizes are such for a reason. There is a proper technique to setting a/f at idle requiring a tachometer with 50rpm sensitivity, you then change to screw settings and look for an increase or decrease in rpm to indicate lean/rich mixture