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Thread: Slipon #628-78055 & Open End Cap Questions

  1. #1
    FOG Guest

    Default Slipon #628-78055 & Open End Cap Questions

    I bought a 2002 FLHTPI that came with the 628-78055 slipons and true dual headpipes. The previous owner installed 16 disks with the closed end cap and some small washers between some of the disks to mimic more disks. Both pipes were black and the bike seemed to smell rich although the plugs looked ok. The engine is the 88" with S&S 510 gear drive cams and a dealer flash for the ECM and a Screamin Eagle air cleaner. I wanted a little louder so I got the open end caps and installed 12 disks per side. I love the sound now. Its loud if I twist it but I can ride beside the law in traffic with no attention.

    Am I in the ball park for the disk/open endcap ratio?

    Will the ratio affect the idle speed if incorrect?

    I did not ride the bike before installing the open endcaps but now when I get back from a ride the bike idles at about 1100-1200 rpm and takes a long time to settle down. On a carb bike this is a sign of lean fuel mixture.

    I will pull the new plugs tomorrow and see what they look like.

    Any ideas or am I chasing more than one problem?? Thanks

  2. #2
    Join Date
    Jul 2007
    Posts
    443

    Default

    Your in the right ball park with the discs.
    Pull the plugs and see what they look like, also check for air leaks, that is more likely if it wasn't doing it before?

  3. #3
    FOG Guest

    Default

    The new plugs I put in look lean. They have about 2 tanks of gas on them. The ones that were in the bike when I got it were rusty brown. I took out 4 disks per side so now its 8+ open caps. I did not ride the bike before I changed things out so I cant say if the idle was an issue.


    I see that the open end caps are more for performance flow than exhaust note so am I wasting my time trying to make this work or is it simply open caps=6 disks??


    It idles @1050-1100 rpm on the tach now so I will see after tomorrows ride how it behaves. If it still does it I will check for air leaks with wd 40 and post back. Thats the only thing I dont like about fuel injection is that you cant tweak it like a carb.

    Are you the same jwells from the TDPRI forum??

    Thanks

  4. #4
    Join Date
    Jul 2007
    Posts
    443

    Default

    Anytime you open it up more or restrict it you are going to effect the sound-weather by adding discs, or an open cap.
    The open cap is equivelant to about 8-9 discs in flow rate. If it's a little on the lean side, taking some out will help.
    Keep us posted.

  5. #5
    FOG Guest

    Default

    I have put it back to the way it was for now> 19 disks and closed end caps. Very well behaved and quite smooth and responsive BUT i have named it chuff chuff. It sounds like a Police bike ha ha.. I have ordered a PCIII USB from http://fuelmotousa.com/power_commander.htm. They are going to map it for the engine setup I have as well as the 12 disk open cap combination. I talked to the engine builder who did the cams and gear drive and was told that the cams are Headquarters Hurricane .500" lift not the S&S 510 like i thought.

    The mufflers sound so good with 12 disks and open end caps that I asked them to map for that. I guess if I get tired of the sound I can turn it down and get the map adjusted. Fuel Moto offers excellent support with that so I dont have to dork with the settings at all.. The slipons are so versitile that it gives you the option to do that without changing mufflers. I love em.

    The Stage 1 flash is not enough for even pipes and air cleaner I have found out.

    I will update as it happens
    Last edited by FOG; 07-27-2009 at 06:11 PM. Reason: Editing, adding

  6. #6

    Default

    Quote Originally Posted by FOG View Post
    I bought a 2002 FLHTPI that came with the 628-78055 slipons and true dual headpipes. The previous owner installed 16 disks with the closed end cap and some small washers between some of the disks to mimic more disks. Both pipes were black and the bike seemed to smell rich although the plugs looked ok. The engine is the 88" with S&S 510 gear drive cams and a dealer flash for the ECM and a Screamin Eagle air cleaner. I wanted a little louder so I got the open end caps and installed 12 disks per side. I love the sound now. Its loud if I twist it but I can ride beside the law in traffic with no attention.

    Am I in the ball park for the disk/open endcap ratio?

    Will the ratio affect the idle speed if incorrect?

    I did not ride the bike before installing the open endcaps but now when I get back from a ride the bike idles at about 1100-1200 rpm and takes a long time to settle down. On a carb bike this is a sign of lean fuel mixture.

    I will pull the new plugs tomorrow and see what they look like.
    Any ideas or am I chasing more than one problem?? Thanks
    I would suggest takiing off a couple of discs on each side? Are you still using the washers? If so take them out also. This should richen you up and get rid of the settle down situation.

  7. #7
    FOG Guest

    Default

    Quote Originally Posted by hugger View Post
    I would suggest takiing off a couple of discs on each side? Are you still using the washers? If so take them out also. This should richen you up and get rid of the settle down situation.
    Quote Originally Posted by FOG View Post
    I have put it back to the way it was for now> 19 disks and closed end caps. Very well behaved and quite smooth and responsive BUT i have named it chuff chuff. It sounds like a Police bike ha ha.. I have ordered a PCIII USB from http://fuelmotousa.com/power_commander.htm. They are going to map it for the engine setup I have as well as the 12 disk open cap combination. I talked to the engine builder who did the cams and gear drive and was told that the cams are Headquarters Hurricane .500" lift not the S&S 510 like i thought.

    The mufflers sound so good with 12 disks and open end caps that I asked them to map for that. I guess if I get tired of the sound I can turn it down and get the map adjusted. Fuel Moto offers excellent support with that so I dont have to dork with the settings at all.. The slipons are so versitile that it gives you the option to do that without changing mufflers. I love em.

    The Stage 1 flash is not enough for even pipes and air cleaner I have found out.

    I will update as it happens
    The idle has returned to normal and it runs fine. I did take off a few disks with the open caps but it did not make much difference so I will wait until the Power Commander shows up. Cheers

  8. #8
    Join Date
    Jul 2007
    Posts
    443

    Default

    Good to hear, keep us posted

  9. #9
    FOG Guest

    Default Update

    I put on the PCIII USB from FuelMoto and although it pulled really well I had a few issues like a missfire@2100 rpm at light cruise as well as a exhaust backfire when I twisted the throttle off idle. I emailed FuelMoto with all of my specs and they sent me a revised map. I loaded that in and went for a cruise a whole different bike now. It pulls like a train and purrs like a kitten. No more high idle issue just a smooth steady nice sounding thump. This revised map really made a difference and I could tell as soon as it started. The pipes are loud when I want but I can still putt around without drawing attention.

    Thats with 12 disks and open caps I very happy camper.

    Cheers, FOG

  10. #10
    Join Date
    Jul 2007
    Posts
    443

    Default

    Very good to hear. Jamie at Fuel Moto is a good guy and know his stuff quite well.

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