Reindeer- I would be very disappointed with your current HP and torque numbers with the parts you have. (SE flat top pistons, Woods cams, head work, and the D&D Fatcat.) I currently have an 07 Fatboy with a stock 96 motor. I put Andrews 48H cams in along with a V&H Pro-pipe and high flow AC. It has a Power Commander V for tuning. No headwork. After dyno tuning, I have 86 hp and 100 TQ. Very close or better than what you have. I think you are leaving alot on the table due to poor tuning. Just my dos pesos....

 

I think your numbers are a little low, but only because of low compression. I have been in the same boat and I have bought into the "go bigger bore" but everyone I know has said the bigger bore only helped because of the bump in compression. If you have the .040 gaskets, 85cc combustion chambers, and the flat tops you are barely at 10:1 compression and the 555 likes the 10.4 to 10.5 range. I think if you have had 50,000 miles since your last top end refresh, go ahead and do the bigger bore 107 with a 3cc domed piston to up the compression. Otherwise you can have the head milled and install a thinner head gasket to up the compression. Use a .030 gasket and cc the chambers and have them milled to 82cc to get right around 10.5:1. If you feel you need to do more then enlarge the intake and exhaust valves and get the larger throttle body. Your Thundermax will make up for everything else.

 

Reindeer,
All good advice given so far; however I have a bit different take on path forward.

First thing I would do is toss the Tmax, replace with the Power Vision and get a good tune; that 103 has never been tuned. If the tune doesn't produce satisfactory results consider the 110" drop in kit, Larry's head upgrade, SE Pro 50mm T/B, Larry's head upgrade and his cam choice. That will get you where you want to be and if you don't beat on the motor, the wheels should hold up.

A 117 motor will require case boring and if you choose that route you might as well have the crank T/B/W and the left crank bearing upgrade. As usual, JMHO.

 

Don't have a high opinion of the TMax?

 

Nothing wrong with them.. All you need is someone who can tune with them.. Base maps will get you close. Especially if you use a later higher numbered map.

 

Sure, but what about the Tmax's self tuning?

 

Thunderhart / Zippers only promoted self tuning early on... Thundermax doesn't really self tune. The main feature behind Tmax is that it does full time closed loop AFR adjustments based on sampling from wide band 02 sensors. Ideally it automagically adjusts the O2 sample to match a determined AFR in a table. The problem is that there are a number of issues that can come up. If the ignition or injector timing is off, the sample can be biased rich or lean (typically sampled lean so motor runs rich). Correct or close to correct ignition timing is critical for a tmax to work. Now thunderheart has done a pretty good job of providing maps that will work OK.. The newer maps are way better than the old ones.

Anyway looking at Reindeer's build it's pretty obvious the motor was never tuned.. It probably got a map for higher compression than what it had.. IIRC the CCP was only 180 psi. If a map was used for a build that had say 200 psi. the AFR will suffer. My bet is that partial throttle timing was way to soft where you spend most of the time riding.. Tmax added fuel and ran rich.

If all you want to do is a build that does not change, you are better off with a flash tuner and a good dyno tuning shop. If you like to change things to see what works best, Tmax is far easier than flash based systems that require special data collection and editing achieve a tune.

 

Thanks. I didn't realize the only table the self tune adjusts is the AFR table. I'll be staying away from the Tmax then

 

Lots of good info here.

There's no question my bike would benefit from some time with a competent tuner. I think the Tmax is a good product, and when I bought it 3 years ago it fit my needs. Whatever direction I go with this build, a pro tune will be the finishing touch. I've been researching Minneapolis area tuners and come up with some good options.

I've pretty much convinced myself that I want the crank serviced and bearings upgraded. It makes a lot more sense to me to spend the money now on a solid foundation, and upgrade the peripherals when I can afford it.

I've got some research and some decisions to make.

 

Not sure why you'd stay away from it.. I've got 2 baggers with Tmaxes, 02 RKC and 07 EGC.

The 02 RKC has had 5-6 exhaust systems. 3 different heads (stock, bigger valve and smaller valve ported/flowed heads), 3 throttle bodies, 2 bores (88 and 95 mostly), 4 cams..

The 07 EGC has had 5-6 exhaust systems, 2 bores (96 and mostly 103 ) 2 different heads (stock and ported), 5 cams, 3 throttle bodies, 2 sets of injectors.

Since I'm an old carb guy and I understand tunng, all of the builds were easy to get close. 1 hour on the dyno could peak the HP/TQ but it was never off more than 3-5%..