Jetting suggestions for 44 IDFs

[alex d]

engine is a 1914, engle w120 on 1.1rockers,  8,5:1 cr, ported 044s with 40x35,5 valves, 1.5 heater boxes and then a 1 5/8 merged header (don't ask), big beef manifolds and a stock mechanical fuel pump (30€ brazilian special)
right now the carbs have in them the following:

36mm vents
50 pump
60 idles
150 mains
200 airs
F11 e-tubes
floats set at 11mm

and it's very rich, smells of gas and puffs black smoke, so...any suggestion?

[Jim Ratto]

move idle down to 55
move main down to 140 or 145

[rick m]

Alex,

I have almost the same engine but a smaller cam. Go down on your idles to 50's or no bigger than 55's.   You do not need that big of an idle jet. Reduce the idle jet and try going up on the main to a 155.  Mine runs smooth as a singer sewing machine with this combo with 32 degrees total advance.

Rick M

[rick m]

Alex,

I have a correction on my post. I pulled my jets today to clean them out and the mains on my motor are 145s with 200 airs. The idle jets are 55s.  Just wanted to clarify my post for you.

Rick M

[Dougy Dee]

Your jetting looks good. What's your fuel pressure?

[rick m]

Hey Doug...Fuel pressure seems to work best at 2-2.5 lbs on the 44 IDFs. I get a clean burn...(slightly rich and a little dark brown on the plug read). I prefer a slightly lighter read but the motor runs cool, works well through the whole rpm range and drives very smooth.

Rick M

[alex d]

Your jetting looks good. What's your fuel pressure?

well, finally got time to check fuel pressure...and surprise, it's at 0,8 bar! (that's 11 psi for you non-metric guys), I checked and the fuel pump pushrod protrudes nearly 15mm instead of 13, so it's time to stack gaskets!