Just bought a 2000 FLHRCI with magnetti marelli fuel injection. Have only put 200 mi. on it. Bought it with 18000 mi.& runs sweet. I've heard many negatives on MM injection, of hard starting & idle issues. I guess the future holds an EFI upgrade for the MM EFI. Any preference on conversion? Thanks

 

Hello and welcome.
Plenty of M & M fuel injected bikes that are over 15 years old and running well.
Consider purchase of a Harley service manual and study the one fuel injection chapter.
The system is rather simple and M & M is /was used in many high priced vehicles.
Some folks have converted to carb for under a grand in new parts but again the unit is workable.
The reality is some techs and mechanics might not be unfamiliar with M & M since they might get 200 or 300 Delphi bikes for every M & M bike...even a bike with a carb is rare for some mechanics.

 

Thanks for your reply. Plan on getting a manual & reading on this site over the long winter here in Maine! Thanks again

 

I went with the S&S VFI system to replace my 2001 MM. You can get the S&S VFI ECM, or the Harley tunable ECM (part number 4000012A) to replace your ECM. This will allow you to custom tune your MM throttle body. Finding one of these ECM's and keeping your throttle body might be your best bet to keep it running right. You might even have one of the Harley tunable ECM's installed on your bike, they were sometimes installed by Harley as a fix for tuning problems. EIther ECM can be tuned with the S&S Pro Tune II software. You can even add an O2 sensor kit for autotune. Once you have one of these ECM's, you can swap out your throttle body for the S&S 52mm or 58mm Single Bore Injection. I run the 52mm on mine with autotune. It took a while for me to get it tuned right, but it runs great now. I'm very happy with my setup.


If you are thinking about an upgrade like this, you'd better hurry. Support for these bikes is disappearing fast, even from the aftermarket companies like S&S. Tuning can also be a problem. S&S has tech's that can help you out over the phone, but you probably won't be able to find anyone outside of S&S that will know how to tune this setup.

 

I did the S&S VFI as well, but went with an HPI throttle body ( 51mm) and had it dyno'd. Have the Auto Tune O2 sensors, but have my head pipes ceramic coated so haven't installed them yet. Runs great. I do have the old MM injection and ECM still, if you should ever have need of some parts.

 

A properly set up MM system can and will run trouble free. The key to this system is a proper "hot/cold idle" set by a knowledgeable tech. This was supposed to be performed as part of regular service intervals, but avoided either because the shop didn't have a tech who could do it or the customer was unwilling to pay for it. If you are set on ditching the system I have priced both efi conversions and carb conversions and the carb will always win out for ease of use and price. In the end you need to decide what is best for your wallet and how much you need or want EFI.

 

thanks for all the information!

 

did you buy just the MM TB or the MMX with delphi injectors ?
been loooking at these , need some advice on HPI MM`s
Thanks ,
JimmyZ

 

Bought the MMX with 1.7 intake runners.

 

so were you happy with the HPI system?
i have a stock TC-88 do you know the runner size I need ?