I recently acquired a 2006 FXSTS (pic below), where the previous to the previous owner (i.e., two owners ago) did a Stage IV to the stock Twin Cam 88. The most recent previous owner didn't know what was involved, and neither do I. An indy shop did the work, and neither of us know which one. The bike appears to have all HD or Screaming Eagle parts, so the Stage IV was mostly likely done with HD/SE parts as well.
So, what would have been typically included in the Stage IV? Yes, I know a Stage IV is a new air cleaner, jugs/pistons, cam, heads and exhaust, but which ones? I'm thinking it went from 88' to 95' as it has SE heads with compression releases, but I don't have a clue on the cam. The bike is actually quite slow until the RPMs really get up there, and then the thing pulls hard, so if there is a choice between a "torque cam" and a "horsepower cam" then it definitely has the horsepower cam (although I generally prefer low-end torque over high-revving horsepower...).
Any thoughts (or link) on what parts/part numbers a typical Stage IV in a TC88 would include? I can't seem to find anything online for an engine this old. Also, what would the shop have tuned this 2006 with (SE tuner or just re-flash stock?). No tuner came with the bike.
I'm looking to make some changes to the motor and it would be nice to know what's currently in it.
Most likely it has the good ported and polished SE heads, 257 cam and 95” jugs. This was a very popular combo on softails of that era. I have a buddy with a 2004 Fatboy with this exact combo. Nothing at all wrong with it and it is a strong runner. If I am correct, and it is tuned properly, it should be producing over 100 hp. I will see if I can find the catalog description and post it here.
I bought an HD Stage III kit, and installed it in my 2003 Heritage in October 2003, just 4 months after I bought it new...
The big bore kits came with the SE203 cams. I later pondered adding SE heads, but I remember reading that the SE203 cams didn't work real well with the SE heads of that era. I believe "stratplexi's" guess of SE 257 is a good one. I also know that some used the SE211 cams with SE heads, but I don't know for sure which ones came in the 88" STage IV kit.
My kit, and all the HD Stage kits needed the purchase of a separate, Harley download cartridge for the tune. They had them for the various stage kits they sold. The one for my kit (#32860-02B) was pretty good. I had it for years and my bike ran really well...
However, around 2013ish I bought a PowerVision tuner for my bagger. I also bought a license for my '03 Heritage (I still own the '03 Heritage). Neither FuelMoto nor DynoJet had a tune specifically for my set-up, so I sent a copy of the tune to DynoJet and they "tweaked" it... Not sure exactly what they did, but it really woke the bike up...!
It would be hard to tell if you have the HD download tune or a dyno tune. Each HD download tune had a Cal-ID number that was basically the part number. The CAL-ID will show in the ECM. I forget how the OEM tunes were numbered, so if you had it dyno tuned and the dyno operator started with HD Stage IV download tune... I suspect you wouldn't be able to tell the difference by reading the ECM.
Ok, closest I could find in my old P&A catelog is Stage IV for a carb bike. It was basically the same config for an EFI bike but the heads may have had a different p/n...cant recall. I can research further if you need the p/n for the heads. At that time, these were the best heads offered by Harley. They also had 2 more radical cams...a 258 and a 260. But the 257 was highly regarded for street use as it came on a little earlier even though it was a HP cam it has a nice torque curve with the right pipes. You can see my scribbles on the prices...that was from 2004 as I was considering this build at the time...lol. I ended up doing something a little cheaper on my 2003 Night Train (95” stock heads reworked and decked, 211 cams). My build ran good but going by memory I think it had around 90 HP. My buddy has the Stage IV EFI build that you have and his bike will keep up with my CVO (Stage IV 117 build). My CVO has 108 HP and we are real close when running them off.
unless something is wrong with it, i would just have someone do a dyno run to see where you are at in terms of the A/F mix and the HP/Tq. Numbers. That would confirm a lot of what we think. And if the run looks good, your all set.
Thanks, guys. This is exactly the type of information I was looking for - you all are awesome! All of this leads me to believe that there is something not optimal about the current tune. There is no way this engine is putting out even close to the numbers in that chart above. Heck, even my ol' 1200 sportster had more torque than this thing does off the line. I previously had a 2006 Dyna TC88 with a Stage I and it had tons of torque compared to this Stage IV. It must be a real bad tune. Guess I'll be looking for a dyno tuner in the LA area.
06-16-2021, 03:52 PM
What's in a Stage IV for a TC88?
