(TRUE STORY)
I once sold a 1990 Jeep Grand Wagoneer, which I had purchased new. It was a grand old 4WD vehicle in perfect condition with every doo-dad that could be ordered on the vehicle. The engine was wonderful at time of my selling. I owned it for 10 years.
The fellow who purchased my Jeep had brought his mechanic with him to look over the vehicle. As they were loading up the Jeep onto the trailer, they kept mumbling about the "hemi" that they were going to drop into the engine compartment. I asked "Why are you going to pull that wonderful, strong V-8 engine out of the Wagoneer and replace it?!"
"Because it's not a hemi", was the reply. Then they drove away.
(as a sidebar: I have absolutely no admiration for the very old technology and performance of the old hemispherical chambered "hemi" motors)

That is the same mindset of pulling the MM EFI and replacing it with a carb. "Because it's not a carb." They want something other than what they are purchasing.

 

Funny how this thread is all people who have the MM trying to convince themselves that a system Harley ditched for the superior Delphi after a few years isn't junk.
It's fuel delivery is unreliable and problematic when doing performance upgrades. Problems with erratic idle was common and it would default to over rich constantly in my limited experience dealing with it on friends' bikes that eventually converted to carb as part of their performance upgrades.
Be prepared to checked the voltage to the TPS, IAC , and ETS and adjust/replace them periodically and deal with availability issues when they go bad and mechanics who won't touch them.
​It's a mentally challenged EFI system that didn't communicate with its sensors in a reliable manner. Unless you already have one, I would avoid it, be prepared to deal with the issues of a sub par EFI system, or convert to carb.

​​​​​​

 

Please read the post by 60Gunner. He has stated the "convert to carb" position accurately.
Some MM EFI owners have no need or desire to "hot-rod" their bikes. So, they have no need to "convince themselves" of anything.

 

Just going by my experience so far which has been good.Runs like a top.Bike has close to 80 k miles and I put about 3 of those on in a couple months before I got the 2012 Ultra.

 

There you go. Limited experience, couldn't figure it out, so convert to carb. EVO EFI must be junk.

carl

 

80K miles & I love the thing! Posted about a temperature sensor I can't find, but not the end yet. The mechanic looking after my bike doesn't seem to want to think about a carb when that injection system gives up the ghost. What would be so difficult if that's where it goes?

 

Well since my bike came
with the MM EFI and the bike only has 18k on it I would like to have it run in that configuration. The bike hasn't run in quite a few years and as of right now all i have invested is an o ring kit. I am more than mechanically able to figure and fix most things so only trying to get an answer as to what issues thier are with it.
if push comes to shove then yes i can convert but only after i have exhausted all options on the MM EFI.

 

The only thing I had to do with my MM injection over 172,000 miles was a throttle position sensor (which I had 'In stock' as I'd bought a fully equipped manifold off a EBay for eventual parts replacement at 100,000 miles. Seemed like a good idea at the time.) 95" Stage II Screamin' Eagle Road Glide. (Keep the air bleeds in the front of the manifold clean!)

 

What the ECM does with the data and how fast/often it polls the sensors is not basically the same in everything injected. Sensors constantly send data. They're the dumb end.

 

Yeah Ok so some ECM's are faster but they still do the same job.They send out a reference voltage and then read what comes back from the sensors and reacts accordingly.As far as polling the sensors that's a constant ongoing process for any EFI system.