People only say that about MMFI because they never took the time to make it work and can't "fix" it.

 

Agreed.

 

I have 84,000 on mine and it runs good after I followed the instructions and clean and made adjustments. I also added a wide band a/f gauge....
The local Harley shop want even attempt to work on the MM fuel injection.

 

RLH, I don't ever recall seeing any gauge of that nature before. Pardon my non knowledge of such an item but, what does it monitor and why?

 

Ran the 4 5/8 crank, headwork, cam, cut the center divider out of the plenom, red injectors, PC3, Wego tuning system. Modded plenom allowed cross talk for a Evo idle and actually opened up the air flow to the engine by before and after AFR readings, the only problems was the MM fuel system was at the edge of fuel delivery at estimated 95-100 hp, only mod left was the higher fuel pressure regulator that would of cured this but started seeing the light at the end of the tunnel.
The MM AFR's stayed consistant, idle qualities were good, performance just didn't seem where it should be and yes wide open throttle was at 13.2 AFR which is optimal pulled the plug on being stubborn and installed a modded CV, Ultima ignition and waalaaa! the engine ran like it should have, the idle went to more of a 'leave this one alone" sound.
The MM can be solid and repairable against what most say but when things go wrong it becomes a balancing act to replace because you can quickly exceed the amount of carb replacement. Some aftermarket EFI's systems out for MM but at what costs is EFI that important to say "I have EFI" I make my living as a foreman overseeing EFI repairs daily and will point blank say A carb on a Evo is clearly a better choice for performance and the direction when things go wrong.

 

It monitors air fuel ratio, so as not to run too lean or too rich.
Adjustments are then made with my power commander III.....

 

Thanks for the video! Got both cold and hot idles straightened out! Trying to decipher those instructions from the service manual was like trying to figure out Chinese arithmetic. There is still a little bit of a hesitation under 2K, but only if you stab the throttle. It isn't really common for me to do that, hard on the bottom end.

 

Spoke too soon...... Cold Idle needs a little bit of tweaking, and the damn return fuel line is leaking again. I changed the o-ring last night before I started on the throttle body, and it stayed perfectly dry. Started it this morning and I bet there was 1/2 cup of gas on the ground within a few minutes. Now to teflon tape the fitting (see if it holds), then replace the line....... The check valve was not leaking last night when I had the line off, so that would mean the line is bad, right? I am ordering a set of braided goodridge lines today. Those lines are about 20 years old, and I'll just replace them while I'm in there. Should be here by Thursday.