JMO moving to 107 alone isn't going to give you that much more power over the 103

As to ported heads, $1400 is high dollar, who's porting them? There are a lot of solid head work shops around and for less money, it's a street bike not a drag racer, and even if you port the heads you'll need to get into the intake, throttle body and check flow, if the heads out flow the intake you haven't accomplished anything but spending money.

A simple head clean up will help increase power.

Just remember to gain hp you must spend $$ and the further up the ladder you go the
larger the $teps....

 

Devilfish,

Not sure who your head porter is so can't comment on the comparision of heads vs. 107 kit and best bang for buck. If one of the following guys is your porter:
John Sachs, WFO Larry, Dave Mackie, Bob Wright, Dan Basiley, R&R (Reggie), or Poorboy (Ron Head) then I would say surely go for headwork.

More cubes are only as good as the heads that are on the bike since your only going up 4 cubes from a 103 to 107, imo I would spend money on the heads than later come back with larger juggs and pistons (107 kit) if necessary.

Depending on year of your bike, you might be better served getting the heads done correcting any issues like pistons in the hole, making sure your cylinders are truly round top middle and bottom setting the CC's and squish correctly to optimize your build. Having the right size intake and flow won't hurt you either. I wouldnt do headwork and not check the cylinders, piston to wall clearances and roundness.

Good luck with the build

 

With the 107" kit you are not only increasing displacement, you are also raising the compression. I would expect gains of as much as 10Hp/10Tq with the right exhaust combination over the factory 103" motor with TW-555 cams. We are actually installing our complete 107" kit on a 103" Ultra Limited as we speak and have another 2010 factory 103" bike here for a TW-555 cam install, I will post dyno results when finished for comparison. A good cylinder head will also offer very good gains, We have seen as much as 10Hp/12Tq with headwork on our 107" builds however results can and will vary greatly based on porting, valve size, etc.. and it is a bit more difficult to estimate the results.

 

Unbalanced---the builder is on your list, but at $1400 plus dyno, its pretty rich for me.

What would the labor be for a 107 ci kit? do I also need a dyno?

 

Just my opinion but you could put a 120 in and it won't perform much better if it doesn't breathe. I have a 103 with ported heads, cams, etc... and it whips my Big Dog with a 117ci. I'm just sayin'

 

Having the factory heads reworked by Branch years ago on my other 2 Harleys gave me the biggest bang. As was stated earlier, cleaning up the stock factory head casts help, valve work for the proper cams used and an .030 Cometic gasket can sure help. Another area where there has been some sloppy casting is the throttle bodies from what I've heard. Cleaning those up will also help. Just my 5 cents.

 

I have Branch heads too. Definitely the best!

 

If you change pistons, and cylinders you will also need a dynotune so that is a wash in either scenario as far as the tuning goes.

Most shops in my area charge 8-10 hours for a top end build. yes they can do it a little faster, but that is the typical charge. Dont forget the added items you will most likely need like adjustable pushrods, new cam bearings, lifters.

IMO and experience heads that flow right and are matched to the cam will give you a better bang for your buck than just throwing cubes and compression at the mix.

If your heads dont compliment your cam, you may not get the improvements where you want them and then you are back at where you are now.

 

I've heard similar stories. Unless you can flow more mixture you can't take advantage of any of the potential that the other performance goodies provide.

Dave Mackie has a great website that discusses the value of flowing heads (no pun intended).

BG

 

A cylinider head that flows the proper amount of air, for the intended build, will also aid in a cool running powerplant.
Scott

 

Scott hit the nail on the head,I have personally seen some of his builds on the dyno..
If power is what you want they know how to get it

 

I'll post the dyno sheet when I get home in a week or so, but bumping compression along with porting the heads and big valves gained me 11hp/12tq above just AC/pipes/cams alone. I'm thinking I might be able to squeeze a few extra ponies out of a ported throttle body and perhaps tw-777 cams instead of the tw6-6.

 

I look at it this way if you are happy with your bike and it runs fine then keep it the way it is and just add a good cam. Doing head work or going to a bigger cubic inch motor cost a lot of Buck$. If you do the math you are only going to gain somewhere between 7 to 12 pound of rear wheel torque, just doing the head work and doing the labor yourself you still have to pay for a performance Dyno tune. You may be paying from $100 to $150 per pound of torque which is a lot of money for not much bang IMO. Wait until the motor has problems that require a top end tear down and do all of your performance upgrades at that time, If the bike is under warranty you could upgrade then if the engine work that is needed to be done requires engine tear down and the warranty covers part of the labor cost which would save you some Buck$ ( that is how I got my 103" upgrade). I am not against performance upgrades, I would like to do some performance upgrades myself but I am waiting until the bike needs the engine rebuilt. JMO

 

I'm of the opinion that if your going for the head porting, might as well
get it over with and add the 103/107 kit as well. You probably will do it at some point in time anyway.
Be prepared though because it will snow ball out of control adding up the other supporting parts to the combination.
Clutch, throttle body rework, and injectors need to be looked at also.

 

If your tearing into it. You might as well do it all and get it tuned once. The thing I wrestle with is at what point do you just get the 120r and have a completely new motor.

 

The 120R's, are about 3/4 point shy of squeeze, need at least a 58mm t/body,(the H-D tbw units DO NOT flow that well), it does not have roller rockers, your going need a good clutch set-up, and a VERY good pipe, along with the compete engine remove/replace.
Once you have your arms around all that, coming in at around 7500-8000, then a purpose-built 98" or 107", looks mighty damn good.
Scott

 

Scott just reminder and to others you can get more out of the 58mm with the TTS it has
Throttle blade control to flow more...... at different throttle %%% settings.
58mm = 2.28inch's
As you can see in the picture your throttle plate does not open all the way until 99%at 2500rpms.
If your tuner understands this this is a great tool to use......... Doc can explains this or Steve from Mastertune. Or my self.
PS: if they dont understand this it can run like a turd if set the wrong way........

Please click on att to see option...
Sorry for the bad picture getting ready to do some tuning this morning.. I did not know how to save as a picture to my PC so I did it from my droid.....