I have a 99 RKC with the MMFI, so far no isssues 28K miles. Done tons of reading on the forums about the MMFI potential issues and options. Has anyone gone from MMFI to Delphi FI on the 2002 and newer bikes? What would be easier and which is more cost effective in the long run? Thx.

 

I've seen how they do the carb conversion ( though I don't know if the cruise control can carry over,) and it seems pretty much straight forward. If I was going away from MMFI, that's what I would consider first.

Going to Delphi Injection would be a nightmare, I'm guessing. The wiring harness swap out alone would be tedious and the sensor requirements would probably not match either.

(132,000 on my MMFI bike btw and it still runs great.)

 

Thats amazing to see a bike with that many miles. A friend of mine has a metric touring bike with 177K and still going. BTW, Stiggy, have you done the SE Hydraulic tensioner upgrade on your bike?

 

99-02's have the strong hot forged cranks with the Timken "Lefty" bearing to support it so I went with gear drive cams back in January 2011 at 81,000 miles.

But the hydraulic kit you're referring to is a no brainer IMO for most folks. Easy to install and should last the life of the bike.

I went with gears because I'm riding this one until it blows up. (So far it still runs like it did 100,000 miles ago. ( But I do keep up with replacing parts too, sometimes even before they break! ))

 

I would go with the carb set up. If I end up keeping my rk I'm definitely going that route sooner or later. I've looked into the delphi set up, but I feel it would be more expensive and more of an a** pain.

 

if you've got the service manual for the 99, it's not hard to keep the MM up and running. Just have to tweek it occasionally. If mine gets to where it has to be changed, I think S&S has a change over which also comes with a new ECM that has it's on usb port. or I might just take that money along with a little more and trade up a few years to get away from the MM...... wouldn't change to anything that does away with cruise.......best thing since sliced bread........

 

MM gets a lot of bad press, but I bet the majority of them are running like clocks, not knowing they should be giving trouble! Consider leaving well alone while it is running OK.

Another option to consider is a direct replacement for MM, which S&S and HD both sell. It comes with improved functionality I understand, compared with MM. I'm not sure that upgrading to Delphi is practical.

 

I think the carb route would be the better choice - that or the S&S or HD replacements that have been mentioned.

Honestly, if it ain't broke, don't fix it. I've got a MM on my '96 Ultra with 62,000+ miles and no issues to this point.

 

Hi all,

I had some issues with me 99 RKC w/ efi last summer. Tuned out a wire from my Big Shot fuel modulator had been making intermittent contact and causing a horrible miss because it had been tied off without enough slack to allow for engine vibrations. My local Harley dealer wanted to do a carb install. As it turned out I went to get the top end done this spring at 80,000 miles and I had to get that Hot Forged crank welded plugged and balanced as the rods were shot. Yellowstone Harley in Belgrade (not my local dealer) did the work and after SE 95 kit, 2008 stock heads (ebay takeoffs) the .510 S&S gear drive already in there she is running better than new, 90 hp 106 lbs torque and getting between 38-40 mpg on interstate @ 80 mph to 47 mpg doing lite cruising. Doesn't miss a beat and runs strong. You just need to find someone who knows how to set it up properly. My understanding is you can't get enough fuel to big motors you need to stay fairly mild in a build but setup right they run good.

goldie

 

I hate carbs. Go with S&S or TMax, IF... thats a big if... you have to do so.

There is nothing wrong with the MM system that a bit of maintenance can't keep in check. Biggest issue I can think of is the throttle plate shaft will wear and start leaking air. That makes for crappy idle. MM stuff is NOT junk... they make very high end systems for Ferrari, etc. Our HD unit got a bit hobbled by MOCO themselves.

Some folks now have the Techno Reasearch Direct Link tuning system that allows a tuner to tune MM, using VE tables, etc. Works pretty good, IMHO.