dru86 wrote:You have to get the main jet size right before the needle jet. The needle jet throttles the main main jet until the slide has lifted all the way up. Changes to either of these two should not change the "choke" as it runs off a different circuit and since the slide is all the way down the needle jet is effectively blocking the main jet.
That's what I thought.... slight overlap between the circuits, but not enough to be easily noticeable.
But then, I've spent some time playing with different sizes (150 to 158), and it would seem main jet alone does have a noticeable effect on the enrichener (regular idle is unaffected).
I also suspect the improvement after 20mm isn't by design, just some unintended air passage opening up due to extremely low fuel level...
Makes no sense, but it would explain why you don't have a problem and I do, despite having correct jetting.
I've left it with the smallest jets I have (152 inner/150 outer, which needed 16.5mm floats and 1.5 on needles)... if I see improvement tomorrow morning, I know I gotta look for some 138-140s...
Have you had a look at something like the innovate wideband kits? These start from under $200 for the basic dial gauge with the sensor. You can spend abit more and get something like the LM1/LM2 which allow you to do data logging and have the option for other inputs (eg rpm, temps, boost, etc). I use the LM1 for my bike and car tuning.
I've looked around for a bit, but I'm still basically clueless as to what's out there. Need to do more research first.
Ideally, I'd find a cheapo sensor, figure out a way to mount it inside the pipe without cutting/welding, then program some standard MCU kit to do data collection/interfacing. Now, the *smart* thing to do would be to get it "good enough", sell, and buy an EFI bike...
