EFI to Carb Conversion 2000 RK

Discussion in 'Engine, Fuel and Exhaust' started by HD RoadKing, Sep 18, 2019.

  1. HD RoadKing

    HD RoadKing New Member

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    I have a Magneti Marelli EFI systen on 2000 RK and it sucks! anyone done this conversion?
    I saw a post on here a while back that was done in 2011 that looked promising but I can't seem to find it anymore.

    Dan
     
  2. dolt

    dolt Senior Member

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    You did not mention if the motor is stock or has been modified which, IMHO, has to be considered in the decision to convert. You say the M&M sucks but what does that mean? IMHO, if the M&M is working and you can find a tuner that knows how to tune the M&M, avoid the cost and expense of converting to carb. On the other hand, if the M&M isn't working, knowledgeable tuner is not available or you just want to make the conversion, then do it.;)

    I have attached a photo documented EFI to carb conversion on a 2005 Softail. The conversion is a bit tedious and time consuming but IMHO worth the cost and effort. JMHO but unless the OP is planning to build a 100HP+ motor, a CV40 would be a suitable carb; plenty available for $50, or therabouts; very easy to modify and tune; lots of jets/needle options, etc.

    I have also attached a list of HD parts others have used to make the conversion. Most are still available but some will have to be found on Ebay. Depending on your approach to the conversion, where parts are purchased, etc., the cost to convert should run between $800-$1000 and, from what I read from guys that have made the conversion it is worth every penny. Some have said that the M&M ECM can be retained but I think it should be replaced.

    One thing I noted in the Two Desperados conversion was leaving all the wires, etc. needed for the EFI on the bike and pushed up under the tank. If I were doing the conversion, I would run those cables down to a connector and remove them from the bike. Also suggest that you Google "Carb to EFI Conversion" and do some research and reading to determine how you are going to make the conversion before you start buying parts.

    Good luck with the project and keep the forum updated on your progress.

    Also suggest that you get the MoCo service manual for your model; the wiring diagrams will come in handy.
     

    Attached Files:

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  3. HD RoadKing

    HD RoadKing New Member

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    Dolt,
    Thanks for the reply. I suppose I should have given more details about the bike and my go forward plan.
    It is internally stock, with K&N air filter and Vance & Hines slip-on's. I have had it tuned twice but that only last's a month or so and then it starts acting up again (erratic idle, back fires, runs rich etc.)
    The motor has 64K original miles on it so I'm planning to pull down the top end this winter. I have a new set of 95" cylinders, pistons and heads to install. The heads are over getting ported and CC'd. I will also be up grading the cam chest with a roller chain conversion kit from Bob Wood. I have yet to decide on cams, that will be done after the CR is determined.
    I'm also trying to decide between a 2-1 exhaust or going with the S&S true duals?
    I did find a complete after market/OEM wiring harness from NAMZ which should help simplify the conversion.
    I could use suggestions on an ignition module though?
    Yes, this is going to set me back a bit but I love this old girl and this is WAY cheaper than a new ride.

    Dan
     
  4. dolt

    dolt Senior Member

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    Understood, sounds like a solid plan. My '02 all bore 107 (recently sold) made 124TQ/110HP running a CV44 carb. I got the tune close and made three pulls on a dyno to dial it in; love a carbed bike. I will likely replace it with an '09-10 FLHX but, unfortunately, not available with a carb and it wouldn't make sense to replace the Delphi EFI with a carb.

    I just don't think a bagger looks right without dual exhaust, so while you might give up a bit of TQ, I would pass on a 2:1 system as well as true duals of any brannd and opt for a 2:1:2 system like the Fuel Moto X pipe; great torque pipe but may give up a couple of HP in peak numbers but we don't ride peak numbers, most of us ride the TQ curve. I ran Rinehart TDs on my the motor reference above but picked up both TQ/HP with the X pipe.

    I believe both Crane and Dynatek and maybe Dayton Twin Tec (not sure) make ignition modules that would work with the conversion; I ran a DTT ignition on my '02 and would think that if you have a complete OEM wiring harness from NAMZ, one of the aftermarket modules made to replace the OEM module on a carbed bike would work; check with NAMZ.

    I would suggest that you take a look at Cyclerama for cam selection. Wes Brown has figured out a cam profile that, in many cases, will generate equal or near equal TQ/HP numbers. I am running the Cyclerama 595 in my 98" FDSTD and that motor is making 115TQ/112HP, not to shabby for a little 98" motor. Those cams like compression, so you need compression releases and patience getting the ignition map matched to the compression.

    Keep us posted on your progress.
     
  5. Harley Cruiser

    Harley Cruiser Member

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    Don you sure know how to make HP and torque, the all bore is the build that I wish I had done with my bottom end build a couple of years ago, for the low end torque, what makes the 88 to 107, a 4 1/8 bore?
    Yea, I'm still a carb guy, my 01 fat took nine months to order and come in, a EFI bike came in before it came in and the dealer was trying to talk me into it, I passed.

     
    Last edited: Sep 20, 2019
  6. dolt

    dolt Senior Member

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    Yes; 4.125"x4.00" is commonly referred to as "all bore" because all the displacement increase comes from the increase in bore diameter; very "torquey" motor. I was quite happy with that motor but when you go to the trouble to split the cases for the case bore, particularly if having the crank addressed, i.e., T/B/W, why not stroke? It just makes sense to stroke the motor as well to 117" or 124". As much as I liked that motor, I would not split 88" cases again and stop af 107". The additional cost is marginal but the increase in performance is a step change.

    High TQ/HP are the result of heads, cams and exhaust playing well together but, as you know, those are peak numbers. A good tuner is necessary to pull it all together to get peak performance at partial throttle where we ride. Most are afraid of higher compression but should not be. The 98" motor referenced in my last post is set up at 11.2 static with CCP at 212psi. The all bore 107" motor was set up at 10.4 static with CCP at 197psi; I ran 87 octane at the compression level and made the TQ/HP number previously posted. Gotta get the right parts but the tune is where it's at.;)

    Smart to pass on the '01 EFI bike; you would be stuck with that MM system and carb conversions were a little more complicated then.
     
  7. Harley Cruiser

    Harley Cruiser Member

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    Well my bottom end rebuild was about 50k ago so not going to split the cases anytime soon. I am tempted in the S&S 100 for the next top end, I ride a lot of dirt/sand roads and lucky to get 100k out of a top end. I like my torque just off idle since I ride a lot of fire trails and need to be able to climb a hill at 1200-1500 rpm in first, second gear. I am wondering how the extra compression would do for the torque at that rpm. I know most people would call that lugging but any faster would put you in a ditch, off a cliff. I'm running a Andrews 21 cam now and like the performance, especially low end, If I go to the 100 I might think about the 26 but my main concern is the 10.5 compression and how that would do lugging it as I often have to do. Do you think it would be a problem, love the idea of the 87 octane. To run that did you have to adjust your timing?
     
  8. dolt

    dolt Senior Member

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    I don't know your definition of a "hill" but climbing a hill at 1200-1500 rpms in second gear would be hard on the crank; first gear not so much. Increase CCP and the crank gets loaded a bit more in that situation bit at the same time is generating more torque. Having said that, the '99-'02 lower units were as close to being bullet proof as possible with the Timken left side bearing and a hot forged crank. Furthermore, if you have been climbing those hills with the current configuration with no issues, a compression bump should be manageable.

    The Daytona Twin Tec ignition module adjusts timing with dials; one for initial advance and one for slope, the rate of advance. I played with the dials until I got "no ping" results and then we put the bike on the dyno, mainly to dial in fuel but the DTT ignition will also allow "universal" changes, i.e., say you want to increase/decrease timing by 2% across the rpm range, you can do that. We made a couple of those adjustments and saw that advancing timing had little affect on HP/TQ at partial throttle. The DTT also allows manual adjustments to timing at specific rpms by 200 rpm increments so we tweaked those a bit to develop the map that I ran. All this was done on 87 octane fuel. I did run 93 octane in the hottest summer months; it gets pretty dang hot in south Texas from July through September and I didn't want to take a chance so I don't know if 87 octane would have been OK in those months or not. I was doing the tuning in late October, early November.

    In general, forget about static CR, look at CCP to make decisions on compression. If you keep CCP between 185-190psi and run a programmable ignition module, you should be able to run 87 octane without issues until ambient temps start to rise above 95*. The OEM ignition module timing is advanced and sometimes, too advanced for a Stage I motor with cams and more than stock compression.
     
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  9. wannaride

    wannaride Active Member

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    On craigslist in colorado springs there has been a Screaming Eagle carb conversion on there for 500.00 in the box.

    Toby