I recently did some homemade mods to my ride and it seems to run just fine other then i did i lose a bit of low end torque i believe.. First I modified the original AC to accept a generic full circle K&N style AC. 2nd i modified a 2010 2-1 RG stock exhaust to fit my 07 FB..I removed the cat, installed bungs for the correct 02 sensor location, a few heavy duty brackets for mounting everything and had the bomber muffler gutted by American Customs Exhaust(site sponsor).

As i understand fuel injection in cagers, and i've been working with them for 30 yrs now, and they've came a looooong way, they have a long term and short term fuel trim to compensate for a small variables in climate, driving conditions etc.. if the short term fuel trim is repeatedly exceeded the limits, the long term fuel trim adjusts up or down accordingly. if the LTFT cannot maintain a base for the STFT to make minor fuel adjustments it should set a code and turn the CEL on.. which neithe rhas happend to me yet. granted i've only put on about 400 miles since the exhaust conversion but like i said it seems to run ok.

Now since i have only increased the air filter size and not the actual throttle bore or intake size, i don't see how the engine can get anymore air in then the stock cleaner.. I know the exhaust is allowing for a higher volume flow and i may install a "mild baffle" just to increase the back pressure some to regain some of my lost torque.

The engine seems to run fine, no surging, no hesitating, no decel popping or high gear lug pinging.. I really don't want to spend the money on a tune program if its not 100% needed.


I guess my question for you folks is, does the factory ECM use STFT and LTFT like cager cars and i am i thinking right or wrong here ? I see from the tyhe stickied thread that they do have LAMBDA so that leads me to believe it has the fuel trim parameters.

I do wish that bikes had the OBDII connector like cager rides, that way i could scan the system and see whats going on..

 

I have an Arlen Ness Big Billet Sucker (Stage II) A/C set up and now installed a Patriot defender 2:1 full system (no cats in headpipes) on my FatBoy. I was anticipating needing a full blown tuner. Now I'm not so sure. The bike is running quite cool, perhaps due to the lack of 2 cats in the pipes. The bike has a variable valve in the exhaust and I have it set to about 70% of full open, which is significantly louder than stock, but not as loud as the V & H straight shots with the quiet baffles installed (!)

The bike pulls like a locomotive from idle...no psychological volume/power thing going on by any means. It has great power throughout the range without the previous "hitting the wall" at moderately high revs. (Though I don't really tach this bike out at all.) The bike is easily able to be one gear higher than normal at all times, and I find myself starting out in second most times, providing that there is no grade. Also, though I try to avoid it from so much conditioning against it, this bike pulls like a rocket from 50 mph in 6th. Even worse is that without realizing it, I once rolled the throttle on while cruising at 40, thinking I was in 5th. There is no decel popping, no flat spots, nothing at all amiss. I will recheck the plugs soon, but so far, so good. Maybe it was the cats, who knows. It seems as though the ECM has totally adjusted to these changes. One more thing...the engine is a bone stock 96B.

 

my 07 is bone stock also. I'm gonna pull the plugs and check tomorrow after another ride to work. I wasn't thinking at the time and i didn't check the plugs before the exhaust change. the muffler looks on the black side inside, maybe some slight graying up in the frt.. hard to tell with a 3' muffler.. lol I'll check them tomorrow and then again at the end of the week. anything questionable and i'll screw a new set of plugs in and see what happens.

like you i don't have any problems on hard pull and seems to have plenty or midrange and upper rpm torque.


I can understand needing to spend the bucks on a tuner package if you're swappin cams or doing a full 103 or higher upgrade, not so sure i'm seeing the need to buy one now.

I was looking at those Patriot pipes and it seems to be a good simple concept and relatively cheap for a HD to boot. If i hadn't of found the right pipes for the right price i would have probably went with those myself.


PS... need to correct a figure in my OP.. its only been 200 miles since the exhaust change over.