jetting advice. start point

so allen and i were playing with a cobra last night, trying to get it up with some shots in the dark.

got a poor idle with the idle screw all the way in and idle air circuit pretty lean.

75 jet, harder to get the idle to hold with a 68. kicks over, not much power.

dollorto 21 race. 75 main, 45 idle, 7 needle, stock diffuser(not sure needle setting)

metra65 puch 1speed previously ported for a polini (matches well i hear) proma gp.

its a similar set up to mine but i have a non ported 2 speed, so we started in that jet range. cant seem to get a good go out of it

which way should we jump looking for it to hold

Re: jetting advice. start point

lower the idle jet, try a 40

Re: jetting advice. start point

david the main jet has little to do with idle i'd up the idle to a 50 just to be safe tho.

Re: jetting advice. start point

i've never ran anything bigger than a 45 idle on the metra fact i think i was running a 42...

Re: jetting advice. start point

yeah yeah. true true.. i was half tuning it with allen, i dont think either of us was paying much attention.

and now i am just tweaked out on coffee at work.... sigh. i want to build!

Re: jetting advice. start point

air/screw mixture will also affect the idle....turn it all the way in then back it out 1turn. this is just a starting point adjust as needed after

Re: jetting advice. start point

🇮🇹💦 Of the Loin /

bring your idle jet down?

on a 19mm gilardoni ive got a 60 and its so rich it dies at idle

Re: jetting advice. start point

check that the float is adjusted right, too.

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