Fellas, my 2005 Fatboy has the 103 SE stroker engine, but the original owner had fitted a Heavy Breather and V&H 2 into 2 but no tuner. It ran so lean I put the original SE2 pipes back on and now it seems very sweet. Obviously it still should have a tuner fitted but I've been too lousy to spend the money considering it seems to be going well and have put about 7,000k's on the clock since putting the SE2s back on. 

I have a service coming up so it might be time to bite the bullet on this. I don't want to spend the money if it can be avoided but do you think it will make a noticable difference to the performance, and am I doing any damage running the Heavy Breather without the tuner?

Thanks guys.

I think you would be doing damage you need to add a tuner

I think use an afr meter, or dyno & see if its lean. If so you need a tuner..

In 2005 to "retune" the fuel injected bikes the Aussie dealers used to use a "one off cartridge" on their digitech computer . Cost about $150 to the customer. A SERT tuner then was $1000 Aussie or thereabouts at the time !! ( $450 in the US !!)

CVO's were also different to the "normal" run bikes, with a specific 103 calibration from the factory.

So your bike may well be 'OK" as is, sure sounds like it.

Is it a Yank import or Aussie from new ? Yank dealers could do a 'stage 1" download without the cartridge business remember !

Also the bike will run better with stock downpipes and "old" SE mufflers as they really were quite freeflow. Yer 'Big nonsense" 2:2 are torque robbers for sure !

If the Harley dealer fitted all the goodies before delivery, then a one off retune OR a SERT would have been with the bike from new !

They don't "Miss you" to coin a phrase.

The one off download cartridges are just that, "junk" after the first use, even on the same bike , so it may not have followed the bike as it changed hands one or more times.

If a SERT had been used on the bike, it's only good for that particular VIN, but is/was reusable MANY times on that bike.

If that's gone AWOL well then "shit happens" and I have heard of several cases where the wee black box ( AKA Dongle ) did not keep up with the bike as it changed hands. Ignorance as opposed to malice for the most part.

A good mate of mine ran his 08 softail for a couple years with S&S pipes and a hi-flo filter. No tuner 0 problems
I would fit a TTS and run a few Vtunes through the bike if it was my bike.
Good luck