Hi everyone,

I've owned my 107 FXBB for just over a year and have felt like it's been lacking power since I bought it. This was confirmed last year when I rode another bike that was a stock 107 FXBB which pulled much more than mine running a stage 1.

With this in mind, I decided to go all in over winter and installed the following as I'd ridden a friend's bike with the same upgrades which saw some great power gains:

S&S 128 big bore kit
Feuling 405 HP+ cam
Feuling 6.1g/s injectors
Screamin Eagle 64mm TB
Changed intake to the new SE heavy breather
(Running V&H short shots & an FP3 tuner)

After completing the above work and having a tune sent across from V&H the bike still feels as though it's being held back. V&H have been brilliant with their contact and trying different maps but nothing seems to be working. The power gain is marginally noticeable and nothing like the 124ci streetbob I'd ridden last year.

The only thing that comes to mind is a problem with the tune, or a historical bad tune prior to me owning the bike which is somehow restricting power. Some other threads have called out speed limiters or rev limiters, but the bike doesn't seem to be strangled by these.

I'm looking to take the bike to dynojet and see if anything can be done away from the FP3 or a full ecu re-flash, but as an example the previous 124ci I'd ridden would pull circa 80mph in 2nd whereas mine will struggle to hit 60mph.

Any advice or guidance would be hugely appreciated before I spend the cash on the dyno.

Many thanks

 

Personally I wouldn't put duals on a big bore build, that tends to shift the power curve to the right.

Welcome to HD Forums.

 

This and getting the bike to a dyno is important.

 

Did you install the latest H-D oil pump with your build? Do yourself a favor and get a proper dyno tune.

 

My call is dump the FP3 and get it dyno tuned then report back and let us know how much happier you are.

 

This, and also the Short Shots are a bad choice if you want to make power.

 

This is why.

 

Ditto on what we one else said. Get rid of the short shots and fp3

 

Nothing wrong with a good set of staggered dual. Short shots ain't one of them.

 

Thanks for the suggestions and responses. However, I struggle to see how a set of pipes can make the bike feel massively restricted versus a 2-1 system? I'll take a look at a new set down the line.

Is anyone aware of any form of ecu restriction? Or would you out this down to a poor previous tune that won't come off when I'm loading a new one? (Note the speed restriction in 2nd gear etc.)