carb set up

[scratchin]

ive just fitted dyno jet kit, bike rides fine and feels much better but is very rich on idle, ive set the pilot screws at two and a half turns out as the instuctions states, i know turning them back in a touch will lean the idle, but is there a method of setting the pilot screws also when i took the carbs off the pilot screws where all different are they supposed to all be the same or not any advice appreciated
cheers tony

[greggo]

This is a personal bug bear of mine, and it's how I measure a decent mechanic from a 'just a job' mechanic.

Setting the screws by the manual is lazy, okay for me and you in the home garage with little experience, but from a workshop, unforgiveable I'm paying for your professinalism. The idea is to get all cylinders fueling the same at idle, there is a huge difference in how one set by the manual, and one set per cylinder feels (Due to the infinite variables from mass production). You won't get increased power, but response and smoothness are markedly better.

As to 'how' I've no idea. Thats why I pay. The last mechanic I know who was any good died last year. Poor bastard.

[marty400]

Is this where dyno tuning comes into play?

Ie. the dyno guy has the diagonistic measuring tools, to do this pilot screw adjustment - as part of the juggling act between different sized jets, Needle Profiles, drilling slides etc!


I imagine when the engine is set up in the factiroy- the Pilot screws are adjusted individually per engine - to get it spot on. Thus - if 1st time adjusting the pilot screws,outside the factory, you must make a note of how many turns, before playing around with it!


Perhaps GFrance can advise?


Cheers
Martin

[scratchin]

the local dyno wants £160 for a set up which i dont want to spend just setting the idle circuit , i remember doing one a few years ago but cant remember properly how it was done, something like setting each carb one by one half way between to lean and to rich just cant quite remember it all (also a mate told me the pilot screws should all be the same and im sure they should be set to each carb then any further adjustments should be equal)

[stimpy]

im no tuner...but at a guess.you would proberly run the 2 middle carbs a tad leaner...
stimpy

[CMSMJ1]

im no tuner...but at a guess.you would proberly run the 2 middle carbs a tad leaner...
stimpy

I am on IL4 guru...but wouldn't you run them richer as they will be hotter??

I bow to your NC23 geek status though Stimpy my good man!

[stimpy]

maybe...im unsure how reliable the info was when i heard it...but summin about the mixture richens as the engine temp rises...could explain why we dont use the choke on hot starts..
just a thought
lol CMSMJ...its true...i luv me 23
stimpy

[sa.racing]

What pilot jets are you using? If your using the stock pilots the extra 1/4 turn out on the mixture screws would be for low rpm cruise and high rpm part throttle operation, You may have to live with the rich idle as a compromise or take it to a dyno for best results, Just out of interest what makes you say its idling rich?
Simon

[scratchin]

on idle it smells realy bad of fuel and the plugs end up black and the bike wont start until i clean the plugs again, (pilot jets control the bike on idle as soon as you rev past about 2000 rpm your off the idle circuit)

[greggo]

You still need an ace mechanic to operate the dyno, it's just another diagnostic tool, they still need to know what to do with the information it gives them.

I've seen blokes tune the idle circuit by ear and come up with a better result than Mr Bythebook. Skill and years of practice.

Have you checked if your choke circuit is stuck part way on?