IDA vents

[davvide]

Hi guys,

another question... 

which vents can I try to start in my IDA?
now I have 37mm vents... (they're correct?)

engine is 90,5x76mm
heads  044 magnum ported with 42x37,5 valve
cam w125

tnx!!!

[67worshipper]

id try the 37s davvide.

[Jim Ratto]

I agree. The 37mm should provide good power to 6700-6800, and good, crisp response off idle, if jetted carefully.
I suggest for your engine:

60F10 idle fuel
110 size idle air/jet holder (you'll have to make these from a 060 or solder up a 120)
150 main
F2 emulsion tube
175 air corrector

be certain float travel/height is set as per Weber specs (you can find them in the Haynes manual or factory Weber book) before anything. A lot of guys chase their tails with jets when float height is the real problem. If your floats have the tab (aside from tab that contacts needle valve) cut it off. It will limit downtravel and keep needle valve from filling bowl.

[davvide]

tomorrow I check the jets...and then I post here

for now, thank you!

[davvide]

now I have:

50F10 idle fuel
120 idle air jet
F7 emulsion tube
135 main
200 air correct

[67worshipper]

whats your cause for concern davvide?

[davvide]

nothing...
I wasn't sure that those vents were good for my engine

[Jim Ratto]

now I have:

50F10 idle fuel
120 idle air jet
F7 emulsion tube
135 main
200 air correct

Bump idle to 60 first, then run car around and see how it comes off idle. Your best idle should occur with mixture screw about 3/4 turn from seated.