stage II 103

Discussion in 'Dyna Models' started by ARTHUR, Jul 8, 2009.

  1. ARTHUR

    ARTHUR New Member

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    2008 fatbob with slip-ons ,filter and download. I want to step up to a 103 with race tuner. What do I need to ask my h-d dealer so I know I'm getting the correct combo?
     
  2. ARTHUR

    ARTHUR New Member

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    Hey thanks for the reply. What do you recommend to do the job the best?
     
  3. ironmark

    ironmark Junior Member

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    I have the 103" stage 2 with the 255 cams & stock heads with a custom FI mapp & I am getting 107lbs of tourqe , the bike has plenty of power & I still get good MPG .
     
  4. dolt

    dolt Senior Member Contributor

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    255 is a nice cam for a bagger; think I would opt for another cam for an FX model. The 255, with a good tune and good exhaust is capable of developing 110-115TQ but it will peak around 3800and HP won't be much more than about 85. If you are stuck on SE cams, take a look at the 251; won't come on as early on the bottom end, exhaust sensitive so you need a good 2:1 system. Will make power to the rev limiter.

    If not stuck to SE cams, take a look at the Andrews 54H.

    It is important to select the cam before you start building and build around the cam. The heads flow fairly well and don't need much work but decking a few thousands off for the compression that makes the cam happy could be required. Flat top pistons and heads decked for compresion, IMHO, make for a more docile, well mannered and easier to tune engine.

    Do the homework; ask questions here or other forums and get the build togehter in your head before you pull the trigger; the results will be predictable, it won't cost as much and, hopefully, no "do overs".

    Just occurred to me that with an FX model you could consider the SE204. It gets a little "smallish" in a 103 and your tech will probably scoff at the idea but the 204 is a very underrated cam, IMHO. I ran one in a 95" Deuce one season and it made 104TQ/94HP and surprised several bigger builds. Nice choppy idle and, in spite of what some will tell you, if set up and TUNED right, it will pull to the rev limiter. Not a good choice for a bagger but for an FX, it could work.
     
    Last edited by a moderator: Jul 8, 2009
  5. ARTHUR

    ARTHUR New Member

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    Thanks,

    What 2-1 exhaust will fit the fat bob
     
  6. Jetstream

    Jetstream New Member

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    Hey Ironmark - I'm looking to do the same upgrade on my 2007 FXDC and have been reading that the 255's drop off around 4500 RPM. I like to run my bike up to 6000 RPM occasionally. Do you notice the 255's dropping off - if so what happens? Does it revert to the stock power curve or is there a noticeable decrease in power? Thanks!