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[kojack]

As most know,  I bought my 2001 serg last year,  with a fully built motor,  hi compression pistons, ported heads, 211 cams, se intake, v&h pro pipe etc.

It came with an old serial PC III that never worked right,  or so I thought,  maybe it did and it was loading up the motor way to much.  I took it off and the bike woke right up.  Started great,  pulls really really great,  runs awesome.  I don't notice any excessive heat from the motor,  get good milage considering what is done to the motor,  and just over all runs STRONG.    I do get some popping on decal.  and had a big backfire for the first time the other day.  the other issue I noticed is some mild surging on constant cruise.  I had my father in laws stock electra glide for an Hr run yesterday and noticed to things.  My bike has about 2 times the HP of his,  and his surges too,  and his is completely stock. 

could my bike have a tune loaded into the stock ECU?

[INDEPENDENT_1]

Sounds lean. Lean can make great power but it can also cause the surging you're describing. It can also seize valves in the guides, bronze your cylinders and other bad stuff. Best bet it get it on a dyno and answer all the question marks.

[kojack]

no dyno close.  have to rely on either fuel moto's pc3 or cobra powerpro.  Im steering towards the latter.  would a plug chop give some what of a picture?

[Twolanerider]

You really need to make the effort to get to a dyno.  Trailer, make it a weekend trip or whatever.  Say this not for any affection for paying dyno operators.  Say this because you don't know what's there.  So you can't know what to load as a map on top.

Power Commander on top of a Marelli ECM is an old and well used option.  It does well for what's needed too.  But the tuning instructions given are, for lack of a better description, additive.  In other words the map in the Power Commander is a set of +/- additions that work on top of the tuning map in the ECM to begin with.

This means that any map you might download, or that Jaimie from Fuel Moto might send you, assumes that your ECM and the ECM in the bike that map was PC3 was developed for are the same.  There map might be, and probably is, built over a map for a stock bike.  You don't know what yours is though.

From your description of the engine it's been worked over.  Perhaps more than once and over the course of many years.  There used to be Race Tuner options (and others) for Marelli bikes.  So your ECM might have been tuned; and it might not have.  You simply don't know (and can't know).  So you can't know if anything you load over the top is working from the same set of instructions or not.  Even if you bought another PC3 or the Cobra device and the bike ran different, seemingly better, you still can't know if it's actually good or really closed to dialed in.

[Twolanerider]

Just actually read your location.  Damn, so getting anywhere isn't an easy option.  In your case I'd hope for a stock ECM (since your bike had Power Commander on it before it's an assumption that isn't too far fetched) then tell Jaimie at Fuel Moto everything I could guess or otherwise figure out about my engine.  The spend the money and hope for the best.  It's not like you really have a ton of options.

[sadunbar]

no dyno close.  have to rely on either fuel moto's pc3 or cobra powerpro.  Im steering towards the latter.  would a plug chop give some what of a picture?

Given the nature of fuels and additives these days, it's increasingly difficult to "read" spark plugs as in the old days.  With plugs not overly effected by fuel additives, light gray is a good result.  The same with your exhaust, gray is good. In very simplistic terms, Gray is good, White is lean, Black (dark gray) is rich.  But as I said, today's fuels and fuel additives can fool you...

[INDEPENDENT_1]

S&S actually manufactures a Magneti Marelli package now that allows you to tune using their pro tune software, a single plenum throttle body and comes with O2 sensors so you can run in closed loop of you wish. PM me if you're interested in one and I'd be happy to set you up with everything including a CVO member discount.

[Twolanerider]

S&S actually manufactures a Magneti Marelli package now that allows you to tune using their pro tune software, a single plenum throttle body and comes with O2 sensors so you can run in closed loop of you wish. PM me if you're interested in one and I'd be happy to set you up with everything including a CVO member discount.

Harley is selling a programmable "service replacement" ECM for the Marelli modules also.  Comes as a blank slate and is programmed much like the S&S modules.  The HD kit is an ECM only though.  Still gives options one never had with the stock ECM.  Is HD # 41000012A. 

The one other option is a retrofit kit from Zippers using the Thundermax module.  It also changes the throttle body to a newer Delphi intake but stays with with the dual pressure and return line setup for fuel lines.  It's a setup that works and does so quite well actually. The Thundermax is by no means "modern tech" but it's still much more capable than the old Marelli box.  It's an interesting upgrade to take an old Marelli bike and load o2 sensors, a more modern intake, lose the old problematic cam position sensor and hang a "smarter" ECM built within the old Marelli form factor.

The S&S kit and the Thundermax kit are neither one cheap packages to buy.  And they are both still very much retrofit kits as they use each company's ECM sandwiched in to the Marelli form factor and kludge together (a bit) the way fuel is fed.  Both work.  No debate there.  Though I've wondered with the continued aging of the Marelli bikes and their consequent declining numbers how much longer such packages will be supported and/or offered built around the Marelli form factor ECMs.

There is one other way to go at it if one is inclined.  It's a bit more work, but not really that much.  Take a little time and watch eBay for a main harness, an engine harness, fuel pump harness and an interconnect harness for a newer bike.  2004-2006 for examples.  All but the Road Glide interconnect harnesses come up regularly and can be had pretty cheaply.  Also keep an eye out for a 2002 and up battery tray, Delphi throttle body, 2002-2007 fuel pump and sending unit assy, an 05 or 06 ECM and a set of gauges for a bike from 2004-2013.

Those are all the big parts to make the old Marelli bike in every way a newer Delphi bike on to which any of the modern tuning packages could be used.  Besides those big parts you need an 18mm plug for the return line hole in the gas tank, a different fuel coupler for the other hole in the tank and the 02 and newer fuel line to go from that fuel coupler to the Delphi throttle body.

If you're willing to be patient and spend a little time catching parts you can do all that for half the cost of the $2000-2500 that are often priced for the Thundermax or S&S kits.  And you end up with a more seamless conversion (no retrofitting, a straight up conversion) when you're done.

[INDEPENDENT_1]

The module that Harley sells is attained through S&S and comes with S&S Pro Tune software. As for Thundermax, they no longer make ECU's for M&M bikes and recently shipped the last ones they had out to other customers in the same boat. I'm an EFI guy and I am currently tuning an M&M bike with the original SERT and prefer EFI flash tuners 99% of the time, however, it's not uncommon and usually much more painless when the M&M's start acting up to put a carb on it and call it a day.

[kojack]

Yeah,  its more than a weekend trip plus LOTS of costs because of the ferry runs.  Then im not even sure if Halifax has a competent dyno tuner there.  That's why I said its not an option.  Even if I swap to the newer system,  im still in the same boat.  It would be easier for me to run a mikuni carb on it...but I would loose my Cruise then.  I am still going to probably go with a fuel moto system after what I have been reading.  Cheap,  and if it runs better than it does now,  im in mega bonus land.  because like I said,  I get a little surge every now and then,  and a bit of popping on decel.  Getting on it,  it pulls HARD.  So,  In the way its running,  its really good.  The PCIII that I took off would not let me tune,  and the bike ran like crap with it on there,  sputtering, popping and not idling or anything.  took it off and the bike woke right up.

[INDEPENDENT_1]

I believe Bobby Wood can set up the CV carbs to run cruise control if that's one of your bigger concerns. At least he can with the bikes that were previously equipped with Delphi EFI. A little more primitive way would be to use the thumb screw that holds the throttle grip.

[Twolanerider]

Yeah,  its more than a weekend trip plus LOTS of costs because of the ferry runs.  Then im not even sure if Halifax has a competent dyno tuner there.  That's why I said its not an option.  Even if I swap to the newer system,  im still in the same boat.  It would be easier for me to run a mikuni carb on it...but I would loose my Cruise then.  I am still going to probably go with a fuel moto system after what I have been reading.  Cheap,  and if it runs better than it does now,  im in mega bonus land.  because like I said,  I get a little surge every now and then,  and a bit of popping on decel.  Getting on it,  it pulls HARD.  So,  In the way its running,  its really good.  The PCIII that I took off would not let me tune,  and the bike ran like crap with it on there,  sputtering, popping and not idling or anything.  took it off and the bike woke right up.

If you're also considering a carb conversion don't let losing the cruise control run you off.  Because you don't have to lose the cruise.

Carb conversion is a relatively painless and less expensive swap than doing a lot of EFI upgrading.  Plus no need to chase EFI tuning once done.  Don't get me wrong, I prefer EFI to carb'd bikes.  But any one of use who has been at this while for awhile knows carb'd bikes can and do run just fine.  I used to carry a separate "altitude" carb in a saddlebag for trips over the mountains.  But aside from the well known and historically constant quirks we all know that a carb'd bike can be just fine.  In your particular set of circumstances it might be a very viable consideration.

Rivera makes a kit that allows connecting cruise control to HSR 42/45/48 Mikuni carbs.  I've not bought one for several years but remember the last time I did the little kit was about $65.  The part number I've got saved is 3042-0004.


Ok, just checked that part number on Amazon and ebay.  Still readily available; but twice as much as what it cost me last time I needed one.  End result, however, is you can still use cruise control with a Mikuni carb if that's the conversion you're considering.

[johnsachs]

Stop pulling your hair out.......Switch to a Mikuni, and call it a day. We won't live with MM bikes here. 
John

[kojack]

Im not really pulling my hair out.  IT is working great.  besides the popping on decel,  and the surge every now and then.  I am going to try the fuel moto unit,  if im not satisfied with that,  then yes,  I am switching to a mikuni cruise controlled carb.

[kojack]

Just looked at my plugs,  greyish tan color and one spark plug has more build up on it compared to the other one.